Overdose
Overdosage with valproate may result in somnolence, heart block, deep coma, and
hypernatremia. Fatalities have been reported; however, patients have recovered from valproate
levels as high as 2,120 mcg/mL.
In overdose situations, the fraction of drug not bound to protein is high and hemodialysis or
tandem hemodialysis plus hemoperfusion may result in significant removal of drug. The benefit
of gastric lavage or emesis will vary with the time since ingestion. General supportive measures
should be applied with particular attention to the maintenance of adequate urinary output.
Naloxone has been reported to reverse the CNS depressant effects of valproate overdosage.
Because naloxone could theoretically also reverse the antiepileptic effects of valproate, it should
be used with caution in patients with epilepsy.
Contraindications
- Depakene should not be administered to patients with hepatic disease or significant hepatic
dysfunction.
- Depakene is contraindicated in patients known to have mitochondrial disorders caused by
mutations in mitochondrial DNA polymerase γ (POLG; e.g., Alpers-Huttenlocher Syndrome)
and children under two years of age who are suspected of having a POLG-related disorder
.
- Depakene is contraindicated in patients with known hypersensitivity to the drug.
- Depakene is contraindicated in patients with known urea cycle disorders.
Undesirable effects
The following serious adverse reactions are described below and elsewhere in the labeling:
- Hepatic failure
- Birth defects
- Decreased IQ following in utero exposure
- Pancreatitis
- Hyperammonemic encephalopathy
- Suicidal behavior and ideation
- Bleeding and other hematopoietic disorders
- Hypothermia
- Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan
hypersensitivity reactions
- Somnolence in the elderly
Because clinical studies are conducted under widely varying conditions, adverse reaction rates
observed in the clinical studies of a drug cannot be directly compared to rates in the clinical
studies of another drug and may not reflect the rates observed in practice.
Epilepsy
The data described in the following section were obtained using Depakote (divalproex sodium)
tablets.
Based on a placebo-controlled trial of adjunctive therapy for treatment of complex partial
seizures, Depakote (divalproex sodium) was generally well tolerated with most adverse reactions
rated as mild to moderate in severity. Intolerance was the primary reason for discontinuation in
the Depakote-treated patients (6%), compared to 1% of placebo-treated patients.
Table 3 lists treatment-emergent adverse reactions which were reported by ≥ 5% of Depakotetreated
patients and for which the incidence was greater than in the placebo group, in a placebocontrolled
trial of adjunctive therapy for treatment of complex partial seizures. Since patients
were also treated with other antiepilepsy drugs, it is not possible, in most cases, to determine
whether the following adverse reactions can be ascribed to Depakote alone, or the combination
of Depakote and other antiepilepsy drugs.
Table 3. Adverse Reactions Reported by ≥ 5% of Patients Treated with Depakote During
Placebo-Controlled Trial of Adjunctive Therapy for Complex Partial Seizures
| Body System/Reaction |
Depakote (%)
(n = 77) |
Placebo (%)
(n = 70) |
| Body as a Whole |
| Headache |
31 |
21 |
| Asthenia |
27 |
7 |
| Fever |
6 |
4 |
| Gastrointestinal System |
| Nausea |
48 |
14 |
| Vomiting |
27 |
7 |
| Abdominal Pain |
23 |
6 |
| Diarrhea |
13 |
6 |
| Anorexia |
12 |
0 |
| Dyspepsia |
8 |
4 |
| Constipation |
5 |
1 |
| Nervous System |
| Tremor |
25 |
6 |
| Somnolence |
27 |
11 |
| Dizziness |
25 |
13 |
| Amblyopia/Blurred Vision |
12 |
9 |
| Diplopia |
16 |
9 |
| Ataxia |
8 |
1 |
| Nystagmus |
8 |
1 |
| Emotional Lability |
6 |
4 |
| Thinking Abnormal |
6 |
0 |
| Amnesia |
5 |
1 |
| Respiratory System |
| Flu Syndrome |
12 |
9 |
| Infection |
12 |
6 |
| Bronchitis |
5 |
1 |
| Rhinitis |
5 |
4 |
| Other |
| Alopecia |
6 |
1 |
| Weight Loss |
6 |
0 |
Table 4 lists treatment-emergent adverse reactions which were reported by ≥ 5% of patients in
the high dose Depakote group, and for which the incidence was greater than in the low dose
group, in a controlled trial of Depakote monotherapy treatment of complex partial seizures. Since
patients were being titrated off another antiepilepsy drug during the first portion of the trial, it is
not possible, in many cases, to determine whether the following adverse reactions can be
ascribed to Depakote alone, or the combination of Depakote and other antiepilepsy drugs.
Table 4. Adverse Reactions Reported by ≥ 5% of Patients in the High Dose Group in the
Controlled Trial of Depakote Monotherapy for Complex Partial Seizures1
| Body System/Reaction |
High Dose (%)
(n = 131) |
Low Dose (%)
(n = 134) |
| Body as a Whole |
| Asthenia |
21 |
10 |
| Digestive System |
| Nausea |
34 |
26 |
| Diarrhea |
23 |
19 |
| Vomiting |
23 |
15 |
| Abdominal Pain |
12 |
9 |
| Anorexia |
11 |
4 |
| Dyspepsia |
11 |
10 |
| Hemic/Lymphatic System |
| Thrombocytopenia |
24 |
1 |
| Ecchymosis |
5 |
4 |
| Metabolic/Nutritional |
| Weight Gain |
9 |
4 |
| Peripheral Edema |
8 |
3 |
| Nervous System |
| Tremor |
57 |
19 |
| Somnolence |
30 |
18 |
| Dizziness |
18 |
13 |
| Insomnia |
15 |
9 |
| Nervousness |
11 |
7 |
| Amnesia |
7 |
4 |
| Nystagmus |
7 |
1 |
| Depression |
5 |
4 |
| Respiratory System |
| Infection |
20 |
13 |
| Pharyngitis |
8 |
2 |
| Dyspnea |
5 |
1 |
| Skin and Appendages |
| Alopecia |
24 |
13 |
| Special Senses |
| Amblyopia/Blurred Vision |
8 |
4 |
| Tinnitus |
7 |
1 |
| 1 Headache was the only adverse reaction that occurred in ≥ 5% of patients in the high dose
group and at an equal or greater incidence in the low dose group. |
The following additional adverse reactions were reported by greater than 1% but less than 5% of
the 358 patients treated with Depakote in the controlled trials of complex partial seizures:
Body as a Whole: Back pain, chest pain, malaise.
Cardiovascular System: Tachycardia, hypertension, palpitation.
Digestive System: Increased appetite, flatulence, hematemesis, eructation, pancreatitis,
periodontal abscess.
Hemic and Lymphatic System: Petechia.
Metabolic and Nutritional Disorders: SGOT increased, SGPT increased.
Musculoskeletal System: Myalgia, twitching, arthralgia, leg cramps, myasthenia.
Nervous System: Anxiety, confusion, abnormal gait, paresthesia, hypertonia, incoordination,
abnormal dreams, personality disorder.
Respiratory System: Sinusitis, cough increased, pneumonia, epistaxis.
Skin and Appendages: Rash, pruritus, dry skin.
Special Senses: Taste perversion, abnormal vision, deafness, otitis media.
Urogenital System: Urinary incontinence, vaginitis, dysmenorrhea, amenorrhea, urinary
frequency.
Mania
Although Depakene has not been evaluated for safety and efficacy in the treatment of manic
episodes associated with bipolar disorder, the following adverse reactions not listed above were
reported by 1% or more of patients from two placebo-controlled clinical trials of Depakote
(divalproex sodium) tablets.
Body as a Whole: Chills, neck pain, neck rigidity.M
Cardiovascular System: Hypotension, postural hypotension, vasodilation.
Digestive System: Fecal incontinence, gastroenteritis, glossitis.
Musculoskeletal System: Arthrosis.
Nervous System: Agitation, catatonic reaction, hypokinesia, reflexes increased, tardive
dyskinesia, vertigo.
Skin and Appendages: Furunculosis, maculopapular rash, seborrhea.
Special Senses: Conjunctivitis, dry eyes, eye pain.
Urogenital System: Dysuria.
Migraine
Although Depakene has not been evaluated for safety and efficacy in the prophylactic treatment
of migraine headaches, the following adverse reactions not listed above were reported by 1% or
more of patients from two placebo-controlled clinical trials of Depakote (divalproex sodium)
tablets.
Body as a Whole: Face edema.
Digestive System: Dry mouth, stomatitis.
Urogenital System: Cystitis, metrorrhagia, and vaginal hemorrhage.
Post-Marketing Experience
The following adverse reactions have been identified during post approval use of Depakote.
Because these reactions are reported voluntarily from a population of uncertain size, it is not
always possible to reliably estimate their frequency or establish a causal relationship to drug
exposure.
Dermatologic: Hair texture changes, hair color changes, photosensitivity, erythema multiforme,
toxic epidermal necrolysis, nail and nail bed disorders, and Stevens-Johnson syndrome.
Psychiatric: Emotional upset, psychosis, aggression, psychomotor hyperactivity, hostility,
disturbance in attention, learning disorder, and behavioral deterioration.
Neurologic: Paradoxical convulsion
There have been several reports of acute or subacute cognitive decline and behavioral changes
(apathy or irritability) with cerebral pseudoatrophy on imaging associated with valproate
therapy; both the cognitive/behavioral changes and cerebral pseudoatrophy reversed partially or
fully after valproate discontinuation.
There have been reports of acute or subacute encephalopathy in the absence of elevated ammonia
levels, elevated valproate levels, or neuroimaging changes. The encephalopathy reversed
partially or fully after valproate discontinuation.
Musculoskeletal: Fractures, decreased bone mineral density, osteopenia, osteoporosis, and
weakness.
Hematologic: Relative lymphocytosis, macrocytosis, leukopenia, anemia including macrocytic
with or without folate deficiency, bone marrow suppression, pancytopenia, aplastic anemia,
agranulocytosis, and acute intermittent porphyria.
Endocrine: Irregular menses, secondary amenorrhea, hyperandrogenism, hirsutism, elevated
testosterone level, breast enlargement, galactorrhea, parotid gland swelling, polycystic ovary
disease, decreased carnitine concentrations, hyponatremia, hyperglycinemia, and inappropriate
ADH secretion.
There have been rare reports of Fanconi’s syndrome occurring chiefly in children.
Metabolism and nutrition: Weight gain.
Reproductive: Aspermia, azoospermia, decreased sperm count, decreased spermatozoa motility,
male infertility, and abnormal spermatozoa morphology.
Genitourinary: Enuresis and urinary tract infection.
Special Senses: Hearing loss.
Other: Allergic reaction, anaphylaxis, developmental delay, bone pain, bradycardia, and
cutaneous vasculitis.
Therapeutic indications
Epilepsy
Depakene (valproic acid) is indicated as monotherapy and adjunctive therapy in the treatment of
patients with complex partial seizures that occur either in isolation or in association with other
types of seizures. Depakene (valproic acid) is indicated for use as sole and adjunctive therapy in
the treatment of simple and complex absence seizures, and adjunctively in patients with multiple
seizure types which include absence seizures.
Simple absence is defined as very brief clouding of the sensorium or loss of consciousness
accompanied by certain generalized epileptic discharges without other detectable clinical signs.
Complex absence is the term used when other signs are also present.
See WARNINGS AND PRECAUTIONS for statement regarding fatal hepatic dysfunction.
Important Limitations
Because of the risk to the fetus of decreased IQ, neural tube defects, and other major congenital
malformations, which may occur very early in pregnancy, valproate should not be administered
to a woman of childbearing potential unless the drug is essential to the management of her
medical condition.
Pharmacodynamic properties
The relationship between plasma concentration and clinical response is not well documented.
One contributing factor is the nonlinear, concentration dependent protein binding of valproate
which affects the clearance of the drug. Thus, monitoring of total serum valproate cannot provide
a reliable index of the bioactive valproate species.
For example, because the plasma protein binding of valproate is concentration dependent, the
free fraction increases from approximately 10% at 40 mcg/mL to 18.5% at 130 mcg/mL. Higher
than expected free fractions occur in the elderly, in hyperlipidemic patients, and in patients with
hepatic and renal diseases.
Epilepsy
The therapeutic range in epilepsy is commonly considered to be 50 to 100 mcg/mL of total
valproate, although some patients may be controlled with lower or higher plasma concentrations.
Pharmacokinetic properties
Absorption/Bioavailability
Equivalent oral doses of Depakote (divalproex sodium) products and Depakene (valproic acid)
capsules deliver equivalent quantities of valproate ion systemically. Although the rate of
valproate ion absorption may vary with the formulation administered (liquid, solid, or sprinkle),
conditions of use (e.g., fasting or postprandial) and the method of administration (e.g., whether
the contents of the capsule are sprinkled on food or the capsule is taken intact), these differences
should be of minor clinical importance under the steady state conditions achieved in chronic use
in the treatment of epilepsy.
However, it is possible that differences among the various valproate products in Tmax and Cmax
could be important upon initiation of treatment. For example, in single dose studies, the effect of
feeding had a greater influence on the rate of absorption of the Depakote tablet (increase in Tmax
from 4 to 8 hours) than on the absorption of the Depakote sprinkle capsules (increase in Tmax
from 3.3 to 4.8 hours).
While the absorption rate from the G.I. tract and fluctuation in valproate plasma concentrations
vary with dosing regimen and formulation, the efficacy of valproate as an anticonvulsant in
chronic use is unlikely to be affected. Experience employing dosing regimens from once-a-day to
four-times-a-day, as well as studies in primate epilepsy models involving constant rate infusion,
indicate that total daily systemic bioavailability (extent of absorption) is the primary determinant
of seizure control and that differences in the ratios of plasma peak to trough concentrations
between valproate formulations are inconsequential from a practical clinical standpoint.
Co-administration of oral valproate products with food and substitution among the various
Depakote and Depakene formulations should cause no clinical problems in the management of
patients with epilepsy. Nonetheless, any changes in
dosage administration, or the addition or discontinuance of concomitant drugs should ordinarily
be accompanied by close monitoring of clinical status and valproate plasma concentrations.
Distribution
Protein Binding
The plasma protein binding of valproate is concentration dependent and the free fraction
increases from approximately 10% at 40 mcg/mL to 18.5% at 130 mcg/mL. Protein binding of
valproate is reduced in the elderly, in patients with chronic hepatic diseases, in patients with
renal impairment, and in the presence of other drugs (e.g., aspirin). Conversely, valproate may
displace certain protein-bound drugs (e.g., phenytoin, carbamazepine, warfarin, and tolbutamide)
.
CNS Distribution
Valproate concentrations in cerebrospinal fluid (CSF) approximate unbound concentrations in
plasma (about 10% of total concentration).
Metabolism
Valproate is metabolized almost entirely by the liver. In adult patients on monotherapy, 30-50%
of an administered dose appears in urine as a glucuronide conjugate. Mitochondrial β-oxidation
is the other major metabolic pathway, typically accounting for over 40% of the dose. Usually,
less than 15-20% of the dose is eliminated by other oxidative mechanisms. Less than 3% of an
administered dose is excreted unchanged in urine.
The relationship between dose and total valproate concentration is nonlinear; concentration does
not increase proportionally with the dose, but rather, increases to a lesser extent due to saturable
plasma protein binding. The kinetics of unbound drug are linear.
Elimination
Mean plasma clearance and volume of distribution for total valproate are 0.56 L/hr/1.73 m2 and
11 L/1.73 m2, respectively. Mean plasma clearance and volume of distribution for free valproate
are 4.6 L/hr/1.73 m2 and 92 L/1.73 m2. Mean terminal half-life for valproate monotherapy ranged
from 9 to 16 hours following oral dosing regimens of 250 to 1,000 mg.
The estimates cited apply primarily to patients who are not taking drugs that affect hepatic
metabolizing enzyme systems. For example, patients taking enzyme-inducing antiepileptic drugs
(carbamazepine, phenytoin, and phenobarbital) will clear valproate more rapidly. Because of
these changes in valproate clearance, monitoring of antiepileptic concentrations should be
intensified whenever concomitant antiepileptics are introduced or withdrawn.
Date of revision of the text
Apr 2017
Fertility, pregnancy and lactation
Pregnancy Category D for epilepsy.
Pregnancy Registry
To collect information on the effects of in utero exposure to Depakene, physicians should
encourage pregnant patients taking Depakene to enroll in the North American Antiepileptic Drug
(NAAED) Pregnancy Registry. This can be done by calling toll free 1-888-233-2334, and must
be done by the patients themselves. Information on the registry can be found at the website,
http://www.aedpregnancyregistry.org/.
Fetal Risk Summary
All pregnancies have a background risk of birth defects (about 3%), pregnancy loss (about 15%),
or other adverse outcomes regardless of drug exposure. Maternal valproate use during pregnancy
for any indication increases the risk of congenital malformations, particularly neural tube defects,
but also malformations involving other body systems (e.g., craniofacial defects, cardiovascular
malformations, hypospadias, limb malformations). The risk of major structural abnormalities is
greatest during the first trimester; however, other serious developmental effects can occur with
valproate use throughout pregnancy. The rate of congenital malformations among babies born to
epileptic mothers who used valproate during pregnancy has been shown to be about four times
higher than the rate among babies born to epileptic mothers who used other anti-seizure
monotherapies.
Several published epidemiological studies have indicated that children exposed to valproate in
utero have lower IQ scores than children exposed to either another antiepileptic drug in utero or
to no antiepileptic drugs in utero.
An observational study has suggested that exposure to valproate products during pregnancy may
increase the risk of autism spectrum disorders. In this study, children born to mothers who had
used valproate products during pregnancy had 2.9 times the risk (95% confidence interval [CI]:
1.7-4.9) of developing autism spectrum disorders compared to children born to mothers not
exposed to valproate products during pregnancy. The absolute risks for autism spectrum
disorders were 4.4% (95% CI: 2.6%-7.5%) in valproate-exposed children and 1.5% (95% CI:
1.5%-1.6%) in children not exposed to valproate products. Because the study was observational
in nature, conclusions regarding a causal association between in utero valproate exposure and an
increased risk of autism spectrum disorder cannot be considered definitive.
In animal studies, offspring with prenatal exposure to valproate had structural malformations
similar to those seen in humans and demonstrated neurobehavioral deficits.
Clinical Considerations
- Neural tube defects are the congenital malformation most strongly associated with maternal
valproate use. The risk of spina bifida following in utero valproate exposure is generally
estimated as 1-2%, compared to an estimated general population risk for spina bifida of about
0.06 to 0.07% (6 to 7 in 10,000 births).
- Valproate can cause decreased IQ scores in children whose mothers were treated with
valproate during pregnancy.
- Because of the risks of decreased IQ, neural tube defects, and other fetal adverse events,
which may occur very early in pregnancy:
- Valproate should not be administered to a woman of childbearing potential unless the
drug is essential to the management of her medical condition. This is especially important
when valproate use is considered for a condition not usually associated with permanent
injury or death (e.g., migraine).
- Valproate should not be used to treat women with epilepsy who are pregnant or who plan
to become pregnant unless other treatments have failed to provide adequate symptom
control or are otherwise unacceptable. In such women, the benefits of treatment with
valproate during pregnancy may still outweigh the risks. When treating a pregnant
woman or a woman of childbearing potential, carefully consider both the potential risks
and benefits of treatment and provide appropriate counseling.
- To prevent major seizures, women with epilepsy should not discontinue valproate abruptly,
as this can precipitate status epilepticus with resulting maternal and fetal hypoxia and threat
to life. Even minor seizures may pose some hazard to the developing embryo or fetus.
However, discontinuation of the drug may be considered prior to and during pregnancy in
individual cases if the seizure disorder severity and frequency do not pose a serious threat to
the patient.
- Available prenatal diagnostic testing to detect neural tube and other defects should be offered
to pregnant women using valproate.
- Evidence suggests that folic acid supplementation prior to conception and during the first
trimester of pregnancy decreases the risk for congenital neural tube defects in the general
population. It is not known whether the risk of neural tube defects or decreased IQ in the
offspring of women receiving valproate is reduced by folic acid supplementation. Dietary
folic acid supplementation both prior to conception and during pregnancy should be routinely
recommended for patients using valproate.
- Pregnant women taking valproate may develop clotting abnormalities including
thrombocytopenia, hypofibrinogenemia, and/or decrease in other coagulation factors, which
may result in hemorrhagic complications in the neonate including death. If valproate is used in pregnancy, the clotting parameters should be
monitored carefully in the mother. If abnormal in the mother, then these parameters should
also be monitored in the neonate.
- Patients taking valproate may develop hepatic failure. Fatal cases of hepatic failure in infants exposed to valproate in utero have
also been reported following maternal use of valproate during pregnancy.
- Hypoglycemia has been reported in neonates whose mothers have taken valproate during
pregnancy.
Data
Human
There is an extensive body of evidence demonstrating that exposure to valproate in utero
increases the risk of neural tube defects and other structural abnormalities. Based on published
data from the CDC’s National Birth Defects Prevention Network, the risk of spina bifida in the
general population is about 0.06 to 0.07%. The risk of spina bifida following in utero valproate
exposure has been estimated to be approximately 1 to 2%.
The NAAED Pregnancy Registry has reported a major malformation rate of 9-11% in the
offspring of women exposed to an average of 1,000 mg/day of valproate monotherapy during
pregnancy. These data show up to a five-fold increased risk for any major malformation
following valproate exposure in utero compared to the risk following exposure in utero to other
antiepileptic drugs taken in monotherapy. The major congenital malformations included cases of
neural tube defects, cardiovascular malformations, craniofacial defects (e.g., oral clefts,
craniosynostosis), hypospadias, limb malformations (e.g., clubfoot, polydactyly), and
malformations of varying severity involving other body systems.
Published epidemiological studies have indicated that children exposed to valproate in utero
have lower IQ scores than children exposed to either another antiepileptic drug in utero or to no
antiepileptic drugs in utero. The largest of these studies is a prospective cohort study conducted
in the United States and United Kingdom that found that children with prenatal exposure to
valproate (n=62) had lower IQ scores at age 6 (97 [95% C.I. 94-101]) than children with prenatal
exposure to the other anti-epileptic drug monotherapy treatments evaluated: lamotrigine (108
[95% C.I. 105-110]), carbamazepine (105 [95% C.I. 102-108]) and phenytoin (108 [95% C.I.
104-112]). It is not known when during pregnancy cognitive effects in valproate-exposed
children occur. Because the women in this study were exposed to antiepileptic drugs throughout
pregnancy, whether the risk for decreased IQ was related to a particular time period during
pregnancy could not be assessed.
Although all of the available studies have methodological limitations, the weight of the evidence
supports a causal association between valproate exposure in utero and subsequent adverse effects
on cognitive development.
There are published case reports of fatal hepatic failure in offspring of women who used
valproate during pregnancy.
Animal
In developmental toxicity studies conducted in mice, rats, rabbits, and monkeys, increased rates
of fetal structural abnormalities, intrauterine growth retardation, and embryo-fetal death occurred
following treatment of pregnant animals with valproate during organogenesis at clinically
relevant doses (calculated on a body surface area basis). Valproate induced malformations of
multiple organ systems, including skeletal, cardiac, and urogenital defects. In mice, in addition to
other malformations, fetal neural tube defects have been reported following valproate
administration during critical periods of organogenesis, and the teratogenic response correlated
with peak maternal drug levels. Behavioral abnormalities (including cognitive, locomotor, and
social interaction deficits) and brain histopathological changes have also been reported in mice
and rat offspring exposed prenatally to clinically relevant doses of valproate.
Qualitative and quantitative composition
Dosage Forms And Strengths
Depakene (valproic acid) is available as orange-colored soft gelatin capsules of 250 mg valproic
acid, bearing the trademark Depakene for product identification, in bottles of 100 capsules and as
a red Oral Solution containing the equivalent of 250 mg valproic acid per 5 mL as the sodium
salt in bottles of 16 ounces.
Storage And Handling
Depakene (valproic acid) is available as orange-colored soft gelatin capsules of 250 mg valproic
acid, bearing the trademark Depakene for product identification, in bottles of 100 capsules (NDC
0074-5681-13), and as a red Oral Solution containing the equivalent of 250 mg valproic acid per
5 mL as the sodium salt in bottles of 16 ounces (NDC 0074-5682-16).
Recommended Storage: Store capsules at 59-77°F (15-25°C). Store Oral Solution below 86°F
(30°C).
Manufactured by: AbbVie LTD, Barceloneta, PR 00617. Revised: Apr 2017
Special warnings and precautions for use
WARNINGS
Included as part of the "PRECAUTIONS" Section
PRECAUTIONS
Hepatotoxicity
General Information On Hepatotoxicity
Hepatic failure resulting in fatalities has occurred in patients receiving valproate. These incidents
usually have occurred during the first six months of treatment. Serious or fatal hepatotoxicity
may be preceded by non-specific symptoms such as malaise, weakness, lethargy, facial edema,
anorexia, and vomiting. In patients with epilepsy, a loss of seizure control may also occur.
Patients should be monitored closely for appearance of these symptoms. Serum liver tests should
be performed prior to therapy and at frequent intervals thereafter, especially during the first six
months of valproate therapy. However, healthcare providers should not rely totally on serum
biochemistry since these tests may not be abnormal in all instances, but should also consider the
results of careful interim medical history and physical examination.
Caution should be observed when administering valproate products to patients with a prior
history of hepatic disease. Patients on multiple anticonvulsants, children, those with congenital
metabolic disorders, those with severe seizure disorders accompanied by mental retardation, and
those with organic brain disease may be at particular risk. See below, “Patients with Known or
Suspected Mitochondrial Disease.”
Experience has indicated that children under the age of two years are at a considerably increased
risk of developing fatal hepatotoxicity, especially those with the aforementioned conditions.
When Depakene products are used in this patient group, they should be used with extreme
caution and as a sole agent. The benefits of therapy should be weighed against the risks. In
progressively older patient groups experience in epilepsy has indicated that the incidence of fatal
hepatotoxicity decreases considerably.
Patients With Known Or Suspected Mitochondrial Disease
Depakene is contraindicated in patients known to have mitochondrial disorders caused by POLG
mutations and children under two years of age who are clinically suspected of having a
mitochondrial disorder. Valproate-induced acute liver failure and
liver-related deaths have been reported in patients with hereditary neurometabolic syndromes
caused by mutations in the gene for mitochondrial DNA polymerase γ (POLG) (e.g., Alpers-
Huttenlocher Syndrome) at a higher rate than those without these syndromes. Most of the
reported cases of liver failure in patients with these syndromes have been identified in children
and adolescents.
POLG-related disorders should be suspected in patients with a family history or suggestive
symptoms of a POLG-related disorder, including but not limited to unexplained encephalopathy,
refractory epilepsy (focal, myoclonic), status epilepticus at presentation, developmental delays,
psychomotor regression, axonal sensorimotor neuropathy, myopathy cerebellar ataxia,
ophthalmoplegia, or complicated migraine with occipital aura. POLG mutation testing should be
performed in accordance with current clinical practice for the diagnostic evaluation of such
disorders. The A467T and W748S mutations are present in approximately 2/3 of patients with
autosomal recessive POLG-related disorders.
In patients over two years of age who are clinically suspected of having a hereditary
mitochondrial disease, Depakene should only be used after other anticonvulsants have failed.
This older group of patients should be closely monitored during treatment with Depakene for the
development of acute liver injury with regular clinical assessments and serum liver test
monitoring.
The drug should be discontinued immediately in the presence of significant hepatic dysfunction,
suspected or apparent. In some cases, hepatic dysfunction has progressed in spite of
discontinuation of drug.
Birth Defects
Valproate can cause fetal harm when administered to a pregnant woman. Pregnancy registry data
show that maternal valproate use can cause neural tube defects and other structural abnormalities
(e.g., craniofacial defects, cardiovascular malformations, hypospadias, limb malformations). The
rate of congenital malformations among babies born to mothers using valproate is about four
times higher than the rate among babies born to epileptic mothers using other anti-seizure
monotherapies. Evidence suggests that folic acid supplementation prior to conception and during
the first trimester of pregnancy decreases the risk for congenital neural tube defects in the
general population.
Decreased IQ Following In Utero Exposure
Valproate can cause decreased IQ scores following in utero exposure. Published epidemiological
studies have indicated that children exposed to valproate in utero have lower cognitive test
scores than children exposed in utero to either another antiepileptic drug or to no antiepileptic
drugs. The largest of these studies1 is a prospective cohort study conducted in the United States
and United Kingdom that found that children with prenatal exposure to valproate (n=62) had
lower IQ scores at age 6 (97 [95% C.I. 94-101]) than children with prenatal exposure to the other
antiepileptic drug monotherapy treatments evaluated: lamotrigine (108 [95% C.I. 105-110]),
carbamazepine (105 [95% C.I. 102-108]), and phenytoin (108 [95% C.I. 104-112]). It is not
known when during pregnancy cognitive effects in valproate-exposed children occur. Because
the women in this study were exposed to antiepileptic drugs throughout pregnancy, whether the
risk for decreased IQ was related to a particular time period during pregnancy could not be
assessed.
Although all of the available studies have methodological limitations, the weight of the evidence
supports the conclusion that valproate exposure in utero can cause decreased IQ in children.
In animal studies, offspring with prenatal exposure to valproate had malformations similar to
those seen in humans and demonstrated neurobehavioral deficits.
Women with epilepsy who are pregnant or who plan to become pregnant should not be treated
with valproate unless other treatments have failed to provide adequate symptom control or are
otherwise unacceptable. In such women, the benefits of treatment with valproate during
pregnancy may still outweigh the risks.
Use In Women Of Childbearing Potential
Because of the risk to the fetus of decreased IQ and major congenital malformations (including
neural tube defects), which may occur very early in pregnancy, valproate should not be
administered to a woman of childbearing potential unless the drug is essential to the management
of her medical condition. This is especially important when valproate use is considered for a
condition not usually associated with permanent injury or death (e.g., migraine). Women should
use effective contraception while using valproate. Women who are planning a pregnancy should
be counseled regarding the relative risks and benefits of valproate use during pregnancy, and
alternative therapeutic options should be considered for these patients.
To prevent major seizures, valproate should not be discontinued abruptly, as this can precipitate
status epilepticus with resulting maternal and fetal hypoxia and threat to life.
Evidence suggests that folic acid supplementation prior to conception and during the first
trimester of pregnancy decreases the risk for congenital neural tube defects in the general
population. It is not known whether the risk of neural tube defects or decreased IQ in the
offspring of women receiving valproate is reduced by folic acid supplementation. Dietary folic
acid supplementation both prior to conception and during pregnancy should be routinely
recommended for patients using valproate.
Pancreatitis
Cases of life-threatening pancreatitis have been reported in both children and adults receiving
valproate. Some of the cases have been described as hemorrhagic with rapid progression from
initial symptoms to death. Some cases have occurred shortly after initial use as well as after
several years of use. The rate based upon the reported cases exceeds that expected in the general
population and there have been cases in which pancreatitis recurred after rechallenge with
valproate. In clinical trials, there were 2 cases of pancreatitis without alternative etiology in
2,416 patients, representing 1,044 patient-years experience. Patients and guardians should be
warned that abdominal pain, nausea, vomiting, and/or anorexia can be symptoms of pancreatitis
that require prompt medical evaluation. If pancreatitis is diagnosed, Depakene should ordinarily
be discontinued. Alternative treatment for the underlying medical condition should be initiated as
clinically indicated.
Urea Cycle Disorders
Depakene is contraindicated in patients with known urea cycle disorders (UCD).
Hyperammonemic encephalopathy, sometimes fatal, has been reported following initiation of
valproate therapy in patients with urea cycle disorders, a group of uncommon genetic
abnormalities, particularly ornithine transcarbamylase deficiency. Prior to the initiation of
Depakene therapy, evaluation for UCD should be considered in the following patients: 1) those
with a history of unexplained encephalopathy or coma, encephalopathy associated with a protein
load, pregnancy-related or postpartum encephalopathy, unexplained mental retardation, or
history of elevated plasma ammonia or glutamine; 2) those with cyclical vomiting and lethargy,
episodic extreme irritability, ataxia, low BUN, or protein avoidance; 3) those with a family
history of UCD or a family history of unexplained infant deaths (particularly males); 4) those
with other signs or symptoms of UCD. Patients who develop symptoms of unexplained
hyperammonemic encephalopathy while receiving valproate therapy should receive prompt
treatment (including discontinuation of valproate therapy) and be evaluated for underlying urea
cycle disorders.
Suicidal Behavior And Ideation
Antiepileptic drugs (AEDs), including Depakene, increase the risk of suicidal thoughts or
behavior in patients taking these drugs for any indication. Patients treated with any AED for any
indication should be monitored for the emergence or worsening of depression, suicidal thoughts
or behavior, and/or any unusual changes in mood or behavior.
Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11
different AEDs showed that patients randomized to one of the AEDs had approximately twice
the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared
to patients randomized to placebo. In these trials, which had a median treatment duration of 12
weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated
patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an
increase of approximately one case of suicidal thinking or behavior for every 530 patients
treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated
patients, but the number is too small to allow any conclusion about drug effect on suicide.
The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one
week after starting drug treatment with AEDs and persisted for the duration of treatment
assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk
of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behavior was generally consistent among drugs in the data
analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a
range of indications suggests that the risk applies to all AEDs used for any indication. The risk
did not vary substantially by age (5-100 years) in the clinical trials analyzed.
Table 2 shows absolute and relative risk by indication for all evaluated AEDs.
Table 2. Risk by indication for antiepileptic drugs in the pooled analysis
| Indication |
Placebo Patients
with Events Per
1,000 Patients |
Drug Patients
with Events Per
1,000 Patients |
Relative Risk:
Incidence
of Events in Drug
Patients/Incidence
in Placebo Patients |
Risk Difference:
Additional Drug
Patients with Events Per
1,000 Patients |
| Epilepsy |
1.0 |
3.4 |
3.5 |
2.4 |
| Psychiatric |
5.7 |
8.5 |
1.5 |
2.9 |
| Other |
1.0 |
1.8 |
1.9 |
0.9 |
| Total |
2.4 |
4.3 |
1.8 |
1.9 |
The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in
clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for
the epilepsy and psychiatric indications.
Anyone considering prescribing Depakene or any other AED must balance the risk of suicidal
thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for
which AEDs are prescribed are themselves associated with morbidity and mortality and an
increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge
during treatment, the prescriber needs to consider whether the emergence of these symptoms in
any given patient may be related to the illness being treated.
Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal
thoughts and behavior and should be advised of the need to be alert for the emergence or
worsening of the signs and symptoms of depression, any unusual changes in mood or behavior,
or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of
concern should be reported immediately to healthcare providers.
Bleeding And Other Hematopoietic Disorders
Valproate is associated with dose-related thrombocytopenia. In a clinical trial of Depakote
(divalproex sodium) as monotherapy in patients with epilepsy, 34/126 patients (27%) receiving
approximately 50 mg/kg/day on average, had at least one value of platelets ≤ 75 x 109/L.
Approximately half of these patients had treatment discontinued, with return of platelet counts to
normal. In the remaining patients, platelet counts normalized with continued treatment. In this
study, the probability of thrombocytopenia appeared to increase significantly at total valproate
concentrations of ≥ 110 mcg/mL (females) or ≥ 135 mcg/mL (males). The therapeutic benefit
which may accompany the higher doses should therefore be weighed against the possibility of a
greater incidence of adverse effects. Valproate use has also been associated with decreases in
other cell lines and myelodysplasia.
Because of reports of cytopenias, inhibition of the secondary phase of platelet aggregation, and
abnormal coagulation parameters, (e.g., low fibrinogen, coagulation factor deficiencies, acquired
von Willebrand’s disease), measurements of complete blood counts and coagulation tests are
recommended before initiating therapy and at periodic intervals. It is recommended that patients
receiving Depakene (valproic acid) be monitored for blood counts and coagulation parameters
prior to planned surgery and during pregnancy. Evidence
of hemorrhage, bruising, or a disorder of hemostasis/coagulation is an indication for reduction of
the dosage or withdrawal of therapy.
Hyperammonemia
Hyperammonemia has been reported in association with valproate therapy and may be present
despite normal liver function tests. In patients who develop unexplained lethargy and vomiting or
changes in mental status, hyperammonemic encephalopathy should be considered and an
ammonia level should be measured. Hyperammonemia should also be considered in patients who
present with hypothermia. If ammonia is increased,
valproate therapy should be discontinued. Appropriate interventions for treatment of
hyperammonemia should be initiated, and such patients should undergo investigation for
underlying urea cycle disorders.
Asymptomatic elevations of ammonia are more common and when present, require close
monitoring of plasma ammonia levels. If the elevation persists, discontinuation of valproate
therapy should be considered.
Hyperammonemia And Encephalopathy Associated With Concomitant Topiramate Use
Concomitant administration of topiramate and valproate has been associated with
hyperammonemia with or without encephalopathy in patients who have tolerated either drug
alone. Clinical symptoms of hyperammonemic encephalopathy often include acute alterations in
level of consciousness and/or cognitive function with lethargy or vomiting. Hypothermia can
also be a manifestation of hyperammonemia. In most
cases, symptoms and signs abated with discontinuation of either drug. This adverse reaction is
not due to a pharmacokinetic interaction. Patients with inborn errors of metabolism or reduced
hepatic mitochondrial activity may be at an increased risk for hyperammonemia with or without
encephalopathy. Although not studied, an interaction of topiramate and valproate may exacerbate
existing defects or unmask deficiencies in susceptible persons. In patients who develop
unexplained lethargy, vomiting, or changes in mental status, hyperammonemic encephalopathy
should be considered and an ammonia level should be measured.
Hypothermia
Hypothermia, defined as an unintentional drop in body core temperature to <35°C (95°F), has
been reported in association with valproate therapy both in conjunction with and in the absence
of hyperammonemia. This adverse reaction can also occur in patients using concomitant
topiramate with valproate after starting topiramate treatment or after increasing the daily dose of
topiramate. Consideration should be given to stopping valproate in
patients who develop hypothermia, which may be manifested by a variety of clinical
abnormalities including lethargy, confusion, coma, and significant alterations in other major
organ systems such as the cardiovascular and respiratory systems. Clinical management and
assessment should include examination of blood ammonia levels.
Drug Reaction With Eosinophilia And Systemic Symptoms (DRESS)/Multiorgan
Hypersensitivity Reactions
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as Multiorgan
Hypersensitivity, has been reported in patients taking valproate. DRESS may be fatal or lifethreatening.
DRESS typically, although not exclusively, presents with fever, rash, and/or
lymphadenopathy, in association with other organ system involvement, such as hepatitis,
nephritis, hematological abnormalities, myocarditis, or myositis sometimes resembling an acute
viral infection. Eosinophilia is often present. Because this disorder is variable in its expression,
other organ systems not noted here may be involved. It is important to note that early
manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even
though rash is not evident. If such signs or symptoms are present, the patient should be evaluated
immediately. Valproate should be discontinued and not be resumed if an alternative etiology for
the signs or symptoms cannot be established.
Interaction With Carbapenem Antibiotics
Carbapenem antibiotics (for example, ertapenem, imipenem, meropenem; this is not a complete
list) may reduce serum valproate concentrations to subtherapeutic levels, resulting in loss of
seizure control. Serum valproate concentrations should be monitored frequently after initiating
carbapenem therapy. Alternative antibacterial or anticonvulsant therapy should be considered if
serum valproate concentrations drop significantly or seizure control deteriorates.
Somnolence In The Elderly
In a double-blind, multicenter trial of valproate in elderly patients with dementia (mean age = 83
years), doses were increased by 125 mg/day to a target dose of 20 mg/kg/day. A significantly
higher proportion of valproate patients had somnolence compared to placebo, and although not
statistically significant, there was a higher proportion of patients with dehydration.
Discontinuations for somnolence were also significantly higher than with placebo. In some
patients with somnolence (approximately one-half), there was associated reduced nutritional
intake and weight loss. There was a trend for the patients who experienced these events to have a
lower baseline albumin concentration, lower valproate clearance, and a higher BUN. In elderly
patients, dosage should be increased more slowly and with regular monitoring for fluid and
nutritional intake, dehydration, somnolence, and other adverse reactions. Dose reductions or
discontinuation of valproate should be considered in patients with decreased food or fluid intake
and in patients with excessive somnolence.
Monitoring
Drug Plasma Concentration
Since valproate may interact with concurrently administered drugs which are capable of enzyme
induction, periodic plasma concentration determinations of valproate and concomitant drugs are
recommended during the early course of therapy.
Effect On Ketone And Thyroid Function Tests
Valproate is partially eliminated in the urine as a keto-metabolite which may lead to a false
interpretation of the urine ketone test.
There have been reports of altered thyroid function tests associated with valproate. The clinical
significance of these is unknown.
Effect On HIV And CMV Viruses Replication
There are in vitro studies that suggest valproate stimulates the replication of the HIV and CMV
viruses under certain experimental conditions. The clinical consequence, if any, is not known.
Additionally, the relevance of these in vitro findings is uncertain for patients receiving
maximally suppressive antiretroviral therapy. Nevertheless, these data should be borne in mind
when interpreting the results from regular monitoring of the viral load in HIV infected patients
receiving valproate or when following CMV infected patients clinically.
Patient Counseling Information
Advise the patient to read the FDA-approved patient labeling (Medication Guide).
Hepatotoxicity
Warn patients and guardians that nausea, vomiting, abdominal pain, anorexia, diarrhea, asthenia,
and/or jaundice can be symptoms of hepatotoxicity and, therefore, require further medical
evaluation promptly.
Pancreatitis
Warn patients and guardians that abdominal pain, nausea, vomiting, and/or anorexia can be
symptoms of pancreatitis and, therefore, require further medical evaluation promptly.
Birth Defects And Decreased IQ
Inform pregnant women and women of childbearing potential that use of valproate during
pregnancy increases the risk of birth defects and decreased IQ in children who were exposed.
Advise women to use effective contraception while using valproate. When appropriate, counsel
these patients about alternative therapeutic options. This is particularly important when valproate
use is considered for a condition not usually associated with permanent injury or death. Advise
patients to read the Medication Guide, which appears as the last section of the labeling.
Advise women of childbearing potential to discuss pregnancy planning with their doctor and to
contact their doctor immediately if they think they are pregnant.
Encourage patients to enroll in the NAAED Pregnancy Registry if they become pregnant. This
registry is collecting information about the safety of antiepileptic drugs during pregnancy. To
enroll, patients can call the toll free number 1-888-233-2334.
Suicidal Thinking And Behavior
Counsel patients, their caregivers, and families that AEDs, including Depakene, may increase the
risk of suicidal thoughts and behavior and to be alert for the emergence or worsening of
symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal
thoughts, behavior, or thoughts about self-harm. Instruct patients, caregivers, and families to
report behaviors of concern immediately to the healthcare providers.
Hyperammonemia
Inform patients of the signs and symptoms associated with hyperammonemic encephalopathy
and to notify the prescriber if any of these symptoms occur.
CNS Depression
Since valproate products may produce CNS depression, especially when combined with another
CNS depressant (e.g., alcohol), advise patients not to engage in hazardous activities, such as
driving an automobile or operating dangerous machinery, until it is known that they do not
become drowsy from the drug.
Multiorgan Hypersensitivity Reactions
Instruct patients that a fever associated with other organ system involvement (rash,
lymphadenopathy, etc.) may be drug-related and should be reported to the physician immediately
.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, And Impairment Of Fertility
Carcinogenesis
Valproate was administered orally to rats and mice at doses of 80 and 170 mg/kg/day (less than
the maximum recommended human dose on a mg/m2 basis) for two years. The primary findings
were an increase in the incidence of subcutaneous fibrosarcomas in high-dose male rats receiving
valproate and a dose-related trend for benign pulmonary adenomas in male mice receiving
valproate. The significance of these findings for humans is unknown.
Mutagenesis
Valproate was not mutagenic in an in vitro bacterial assay (Ames test), did not produce dominant
lethal effects in mice, and did not increase chromosome aberration frequency in an in vivo
cytogenetic study in rats. Increased frequencies of sister chromatid exchange (SCE) have been
reported in a study of epileptic children taking valproate, but this association was not observed in
another study conducted in adults. There is some evidence that increased SCE frequencies may
be associated with epilepsy. The biological significance of an increase in SCE frequency is not
known.
Impairment Of Fertility
Chronic toxicity studies of valproate in juvenile and adult rats and dogs demonstrated reduced
spermatogenesis and testicular atrophy at oral doses of 400 mg/kg/day or greater in rats
(approximately equivalent to or greater than the maximum recommended human dose (MRHD)
on a mg/m2 basis) and 150 mg/kg/day or greater in dogs (approximately 1.4 times the MRHD or
greater on a mg/m2 basis). Fertility studies in rats have shown no effect on fertility at oral doses
of valproate up to 350 mg/kg/day (approximately equal to the MRHD on a mg/m2 basis) for 60
days. The effect of valproate on testicular development and on sperm parameters and fertility in
humans is unknown.
Use In Specific Populations
Pregnancy
Pregnancy Category D for epilepsy.
Pregnancy Registry
To collect information on the effects of in utero exposure to Depakene, physicians should
encourage pregnant patients taking Depakene to enroll in the North American Antiepileptic Drug
(NAAED) Pregnancy Registry. This can be done by calling toll free 1-888-233-2334, and must
be done by the patients themselves. Information on the registry can be found at the website,
http://www.aedpregnancyregistry.org/.
Fetal Risk Summary
All pregnancies have a background risk of birth defects (about 3%), pregnancy loss (about 15%),
or other adverse outcomes regardless of drug exposure. Maternal valproate use during pregnancy
for any indication increases the risk of congenital malformations, particularly neural tube defects,
but also malformations involving other body systems (e.g., craniofacial defects, cardiovascular
malformations, hypospadias, limb malformations). The risk of major structural abnormalities is
greatest during the first trimester; however, other serious developmental effects can occur with
valproate use throughout pregnancy. The rate of congenital malformations among babies born to
epileptic mothers who used valproate during pregnancy has been shown to be about four times
higher than the rate among babies born to epileptic mothers who used other anti-seizure
monotherapies.
Several published epidemiological studies have indicated that children exposed to valproate in
utero have lower IQ scores than children exposed to either another antiepileptic drug in utero or
to no antiepileptic drugs in utero.
An observational study has suggested that exposure to valproate products during pregnancy may
increase the risk of autism spectrum disorders. In this study, children born to mothers who had
used valproate products during pregnancy had 2.9 times the risk (95% confidence interval [CI]:
1.7-4.9) of developing autism spectrum disorders compared to children born to mothers not
exposed to valproate products during pregnancy. The absolute risks for autism spectrum
disorders were 4.4% (95% CI: 2.6%-7.5%) in valproate-exposed children and 1.5% (95% CI:
1.5%-1.6%) in children not exposed to valproate products. Because the study was observational
in nature, conclusions regarding a causal association between in utero valproate exposure and an
increased risk of autism spectrum disorder cannot be considered definitive.
In animal studies, offspring with prenatal exposure to valproate had structural malformations
similar to those seen in humans and demonstrated neurobehavioral deficits.
Clinical Considerations
- Neural tube defects are the congenital malformation most strongly associated with maternal
valproate use. The risk of spina bifida following in utero valproate exposure is generally
estimated as 1-2%, compared to an estimated general population risk for spina bifida of about
0.06 to 0.07% (6 to 7 in 10,000 births).
- Valproate can cause decreased IQ scores in children whose mothers were treated with
valproate during pregnancy.
- Because of the risks of decreased IQ, neural tube defects, and other fetal adverse events,
which may occur very early in pregnancy:
- Valproate should not be administered to a woman of childbearing potential unless the
drug is essential to the management of her medical condition. This is especially important
when valproate use is considered for a condition not usually associated with permanent
injury or death (e.g., migraine).
- Valproate should not be used to treat women with epilepsy who are pregnant or who plan
to become pregnant unless other treatments have failed to provide adequate symptom
control or are otherwise unacceptable. In such women, the benefits of treatment with
valproate during pregnancy may still outweigh the risks. When treating a pregnant
woman or a woman of childbearing potential, carefully consider both the potential risks
and benefits of treatment and provide appropriate counseling.
- To prevent major seizures, women with epilepsy should not discontinue valproate abruptly,
as this can precipitate status epilepticus with resulting maternal and fetal hypoxia and threat
to life. Even minor seizures may pose some hazard to the developing embryo or fetus.
However, discontinuation of the drug may be considered prio
Dosage (Posology) and method of administration
Epilepsy
Depakene is intended for oral administration. Depakene capsules should be swallowed whole
without chewing to avoid local irritation of the mouth and throat.
Patients should be informed to take Depakene every day as prescribed. If a dose is missed it
should be taken as soon as possible, unless it is almost time for the next dose. If a dose is
skipped, the patient should not double the next dose.
Depakene is indicated as monotherapy and adjunctive therapy in complex partial seizures in
adults and pediatric patients down to the age of 10 years, and in simple and complex absence
seizures. As the Depakene dosage is titrated upward, concentrations of clonazepam, diazepam,
ethosuximide, lamotrigine, tolbutamide, phenobarbital, carbamazepine, and/or phenytoin may be
affected.
Complex Partial Seizures
For adults and children 10 years of age or older.
Monotherapy (Initial Therapy)
Depakene has not been systematically studied as initial therapy. Patients should initiate therapy
at 10 to 15 mg/kg/day. The dosage should be increased by 5 to 10 mg/kg/week to achieve
optimal clinical response. Ordinarily, optimal clinical response is achieved at daily doses below
60 mg/kg/day. If satisfactory clinical response has not been achieved, plasma levels should be
measured to determine whether or not they are in the usually accepted therapeutic range (50 to
100 mcg/mL). No recommendation regarding the safety of valproate for use at doses above 60
mg/kg/day can be made.
The probability of thrombocytopenia increases significantly at total trough valproate plasma
concentrations above 110 mcg/mL in females and 135 mcg/mL in males. The benefit of
improved seizure control with higher doses should be weighed against the possibility of a greater
incidence of adverse reactions.
Conversion to Monotherapy
Patients should initiate therapy at 10 to 15 mg/kg/day. The dosage should be increased by 5 to 10
mg/kg/week to achieve optimal clinical response. Ordinarily, optimal clinical response is
achieved at daily doses below 60 mg/kg/day. If satisfactory clinical response has not been
achieved, plasma levels should be measured to determine whether or not they are in the usually
accepted therapeutic range (50-100 mcg/mL). No recommendation regarding the safety of
valproate for use at doses above 60 mg/kg/day can be made. Concomitant antiepilepsy drug
(AED) dosage can ordinarily be reduced by approximately 25% every 2 weeks. This reduction
may be started at initiation of Depakene therapy, or delayed by 1 to 2 weeks if there is a concern
that seizures are likely to occur with a reduction. The speed and duration of withdrawal of the
concomitant AED can be highly variable, and patients should be monitored closely during this
period for increased seizure frequency.
Adjunctive Therapy
Depakene may be added to the patient’s regimen at a dosage of 10 to 15 mg/kg/day. The dosage
may be increased by 5 to 10 mg/kg/week to achieve optimal clinical response. Ordinarily,
optimal clinical response is achieved at daily doses below 60 mg/kg/day. If satisfactory clinical
response has not been achieved, plasma levels should be measured to determine whether or not
they are in the usually accepted therapeutic range (50 to 100 mcg/mL). No recommendation
regarding the safety of valproate for use at doses above 60 mg/kg/day can be made. If the total
daily dose exceeds 250 mg, it should be given in divided doses.
In a study of adjunctive therapy for complex partial seizures in which patients were receiving
either carbamazepine or phenytoin in addition to Depakote tablets, no adjustment of
carbamazepine or phenytoin dosage was needed. However, since
valproate may interact with these or other concurrently administered AEDs as well as other
drugs, periodic plasma concentration determinations of concomitant AEDs are recommended
during the early course of therapy.
Simple And Complex Absence Seizures
The recommended initial dose is 15 mg/kg/day, increasing at one week intervals by 5 to 10
mg/kg/day until seizures are controlled or side effects preclude further increases. The maximum
recommended dosage is 60 mg/kg/day. If the total daily dose exceeds 250 mg, it should be given
in divided doses.
A good correlation has not been established between daily dose, serum concentrations, and
therapeutic effect. However, therapeutic valproate serum concentration for most patients with
absence seizures is considered to range from 50 to 100 mcg/mL. Some patients may be
controlled with lower or higher serum concentrations.
As the Depakene dosage is titrated upward, blood concentrations of phenobarbital and/or
phenytoin may be affected.
Antiepilepsy drugs should not be abruptly discontinued in patients in whom the drug is
administered to prevent major seizures because of the strong possibility of precipitating status
epilepticus with attendant hypoxia and threat to life.
The following Table is a guide for the initial daily dose of Depakene (valproic acid) (15
mg/kg/day):
Table 1. Initial Daily Dose
| Weight |
Total Daily Dose (mg) |
Number of Capsules or
Teaspoonfuls of Syrup |
| (Kg) |
(Lb) |
|
Dose 1 |
Dose 2 |
Dose 3 |
| 10 - 24.9 |
22 - 54.9 |
250 |
0 |
0 |
1 |
| 25 - 39.9 |
55 - 87.9 |
500 |
1 |
0 |
1 |
| 40 - 59.9 |
88 - 131.9 |
750 |
1 |
1 |
1 |
| 60 - 74.9 |
132 - 164.9 |
1,000 |
1 |
1 |
2 |
| 75 - 89.9 |
165 - 197.9 |
1,250 |
2 |
1 |
2 |
General Dosing Advice
Dosing In Elderly Patients
Due to a decrease in unbound clearance of valproate and possibly a greater sensitivity to
somnolence in the elderly, the starting dose should be reduced in these patients. Dosage should
be increased more slowly and with regular monitoring for fluid and nutritional intake,
dehydration, somnolence, and other adverse reactions. Dose reductions or discontinuation of
valproate should be considered in patients with decreased food or fluid intake and in patients
with excessive somnolence. The ultimate therapeutic dose should be achieved on the basis of
both tolerability and clinical response.
Dose-Related Adverse Reactions
The frequency of adverse effects (particularly elevated liver enzymes and thrombocytopenia)
may be dose-related. The probability of thrombocytopenia appears to increase significantly at
total valproate concentrations of ≥ 110 mcg/mL (females) or ≥ 135 mcg/mL (males). The benefit of improved therapeutic effect with higher doses
should be weighed against the possibility of a greater incidence of adverse reactions.
G.I. Irritation
Patients who experience G.I. irritation may benefit from administration of the drug with food or
by slowly building up the dose from an initial low level.
Dosing In Patients Taking Rufinamide
Patients stabilized on rufinamide before being prescribed valproate should begin valproate
therapy at a low dose, and titrate to a clinically effective dose.
Interaction with other medicinal products and other forms of interaction
SIDE EFFECTS
The following serious adverse reactions are described below and elsewhere in the labeling:
- Hepatic failure
- Birth defects
- Decreased IQ following in utero exposure
- Pancreatitis
- Hyperammonemic encephalopathy
- Suicidal behavior and ideation
- Bleeding and other hematopoietic disorders
- Hypothermia
- Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan
hypersensitivity reactions
- Somnolence in the elderly
Because clinical studies are conducted under widely varying conditions, adverse reaction rates
observed in the clinical studies of a drug cannot be directly compared to rates in the clinical
studies of another drug and may not reflect the rates observed in practice.
Epilepsy
The data described in the following section were obtained using Depakote (divalproex sodium)
tablets.
Based on a placebo-controlled trial of adjunctive therapy for treatment of complex partial
seizures, Depakote (divalproex sodium) was generally well tolerated with most adverse reactions
rated as mild to moderate in severity. Intolerance was the primary reason for discontinuation in
the Depakote-treated patients (6%), compared to 1% of placebo-treated patients.
Table 3 lists treatment-emergent adverse reactions which were reported by ≥ 5% of Depakotetreated
patients and for which the incidence was greater than in the placebo group, in a placebocontrolled
trial of adjunctive therapy for treatment of complex partial seizures. Since patients
were also treated with other antiepilepsy drugs, it is not possible, in most cases, to determine
whether the following adverse reactions can be ascribed to Depakote alone, or the combination
of Depakote and other antiepilepsy drugs.
Table 3. Adverse Reactions Reported by ≥ 5% of Patients Treated with Depakote During
Placebo-Controlled Trial of Adjunctive Therapy for Complex Partial Seizures
| Body System/Reaction |
Depakote (%)
(n = 77) |
Placebo (%)
(n = 70) |
| Body as a Whole |
| Headache |
31 |
21 |
| Asthenia |
27 |
7 |
| Fever |
6 |
4 |
| Gastrointestinal System |
| Nausea |
48 |
14 |
| Vomiting |
27 |
7 |
| Abdominal Pain |
23 |
6 |
| Diarrhea |
13 |
6 |
| Anorexia |
12 |
0 |
| Dyspepsia |
8 |
4 |
| Constipation |
5 |
1 |
| Nervous System |
| Tremor |
25 |
6 |
| Somnolence |
27 |
11 |
| Dizziness |
25 |
13 |
| Amblyopia/Blurred Vision |
12 |
9 |
| Diplopia |
16 |
9 |
| Ataxia |
8 |
1 |
| Nystagmus |
8 |
1 |
| Emotional Lability |
6 |
4 |
| Thinking Abnormal |
6 |
0 |
| Amnesia |
5 |
1 |
| Respiratory System |
| Flu Syndrome |
12 |
9 |
| Infection |
12 |
6 |
| Bronchitis |
5 |
1 |
| Rhinitis |
5 |
4 |
| Other |
| Alopecia |
6 |
1 |
| Weight Loss |
6 |
0 |
Table 4 lists treatment-emergent adverse reactions which were reported by ≥ 5% of patients in
the high dose Depakote group, and for which the incidence was greater than in the low dose
group, in a controlled trial of Depakote monotherapy treatment of complex partial seizures. Since
patients were being titrated off another antiepilepsy drug during the first portion of the trial, it is
not possible, in many cases, to determine whether the following adverse reactions can be
ascribed to Depakote alone, or the combination of Depakote and other antiepilepsy drugs.
Table 4. Adverse Reactions Reported by ≥ 5% of Patients in the High Dose Group in the
Controlled Trial of Depakote Monotherapy for Complex Partial Seizures1
| Body System/Reaction |
High Dose (%)
(n = 131) |
Low Dose (%)
(n = 134) |
| Body as a Whole |
| Asthenia |
21 |
10 |
| Digestive System |
| Nausea |
34 |
26 |
| Diarrhea |
23 |
19 |
| Vomiting |
23 |
15 |
| Abdominal Pain |
12 |
9 |
| Anorexia |
11 |
4 |
| Dyspepsia |
11 |
10 |
| Hemic/Lymphatic System |
| Thrombocytopenia |
24 |
1 |
| Ecchymosis |
5 |
4 |
| Metabolic/Nutritional |
| Weight Gain |
9 |
4 |
| Peripheral Edema |
8 |
3 |
| Nervous System |
| Tremor |
57 |
19 |
| Somnolence |
30 |
18 |
| Dizziness |
18 |
13 |
| Insomnia |
15 |
9 |
| Nervousness |
11 |
7 |
| Amnesia |
7 |
4 |
| Nystagmus |
7 |
1 |
| Depression |
5 |
4 |
| Respiratory System |
| Infection |
20 |
13 |
| Pharyngitis |
8 |
2 |
| Dyspnea |
5 |
1 |
| Skin and Appendages |
| Alopecia |
24 |
13 |
| Special Senses |
| Amblyopia/Blurred Vision |
8 |
4 |
| Tinnitus |
7 |
1 |
| 1 Headache was the only adverse reaction that occurred in ≥ 5% of patients in the high dose
group and at an equal or greater incidence in the low dose group. |
The following additional adverse reactions were reported by greater than 1% but less than 5% of
the 358 patients treated with Depakote in the controlled trials of complex partial seizures:
Body as a Whole: Back pain, chest pain, malaise.
Cardiovascular System: Tachycardia, hypertension, palpitation.
Digestive System: Increased appetite, flatulence, hematemesis, eructation, pancreatitis,
periodontal abscess.
Hemic and Lymphatic System: Petechia.
Metabolic and Nutritional Disorders: SGOT increased, SGPT increased.
Musculoskeletal System: Myalgia, twitching, arthralgia, leg cramps, myasthenia.
Nervous System: Anxiety, confusion, abnormal gait, paresthesia, hypertonia, incoordination,
abnormal dreams, personality disorder.
Respiratory System: Sinusitis, cough increased, pneumonia, epistaxis.
Skin and Appendages: Rash, pruritus, dry skin.
Special Senses: Taste perversion, abnormal vision, deafness, otitis media.
Urogenital System: Urinary incontinence, vaginitis, dysmenorrhea, amenorrhea, urinary
frequency.
Mania
Although Depakene has not been evaluated for safety and efficacy in the treatment of manic
episodes associated with bipolar disorder, the following adverse reactions not listed above were
reported by 1% or more of patients from two placebo-controlled clinical trials of Depakote
(divalproex sodium) tablets.
Body as a Whole: Chills, neck pain, neck rigidity.M
Cardiovascular System: Hypotension, postural hypotension, vasodilation.
Digestive System: Fecal incontinence, gastroenteritis, glossitis.
Musculoskeletal System: Arthrosis.
Nervous System: Agitation, catatonic reaction, hypokinesia, reflexes increased, tardive
dyskinesia, vertigo.
Skin and Appendages: Furunculosis, maculopapular rash, seborrhea.
Special Senses: Conjunctivitis, dry eyes, eye pain.
Urogenital System: Dysuria.
Migraine
Although Depakene has not been evaluated for safety and efficacy in the prophylactic treatment
of migraine headaches, the following adverse reactions not listed above were reported by 1% or
more of patients from two placebo-controlled clinical trials of Depakote (divalproex sodium)
tablets.
Body as a Whole: Face edema.
Digestive System: Dry mouth, stomatitis.
Urogenital System: Cystitis, metrorrhagia, and vaginal hemorrhage.
Post-Marketing Experience
The following adverse reactions have been identified during post approval use of Depakote.
Because these reactions are reported voluntarily from a population of uncertain size, it is not
always possible to reliably estimate their frequency or establish a causal relationship to drug
exposure.
Dermatologic: Hair texture changes, hair color changes, photosensitivity, erythema multiforme,
toxic epidermal necrolysis, nail and nail bed disorders, and Stevens-Johnson syndrome.
Psychiatric: Emotional upset, psychosis, aggression, psychomotor hyperactivity, hostility,
disturbance in attention, learning disorder, and behavioral deterioration.
Neurologic: Paradoxical convulsion
There have been several reports of acute or subacute cognitive decline and behavioral changes
(apathy or irritability) with cerebral pseudoatrophy on imaging associated with valproate
therapy; both the cognitive/behavioral changes and cerebral pseudoatrophy reversed partially or
fully after valproate discontinuation.
There have been reports of acute or subacute encephalopathy in the absence of elevated ammonia
levels, elevated valproate levels, or neuroimaging changes. The encephalopathy reversed
partially or fully after valproate discontinuation.
Musculoskeletal: Fractures, decreased bone mineral density, osteopenia, osteoporosis, and
weakness.
Hematologic: Relative lymphocytosis, macrocytosis, leukopenia, anemia including macrocytic
with or without folate deficiency, bone marrow suppression, pancytopenia, aplastic anemia,
agranulocytosis, and acute intermittent porphyria.
Endocrine: Irregular menses, secondary amenorrhea, hyperandrogenism, hirsutism, elevated
testosterone level, breast enlargement, galactorrhea, parotid gland swelling, polycystic ovary
disease, decreased carnitine concentrations, hyponatremia, hyperglycinemia, and inappropriate
ADH secretion.
There have been rare reports of Fanconi’s syndrome occurring chiefly in children.
Metabolism and nutrition: Weight gain.
Reproductive: Aspermia, azoospermia, decreased sperm count, decreased spermatozoa motility,
male infertility, and abnormal spermatozoa morphology.
Genitourinary: Enuresis and urinary tract infection.
Special Senses: Hearing loss.
Other: Allergic reaction, anaphylaxis, developmental delay, bone pain, bradycardia, and
cutaneous vasculitis.
DRUG INTERACTIONS
Effects Of Co-Administered Drugs On Valproate Clearance
Drugs that affect the level of expression of hepatic enzymes, particularly those that elevate levels
of glucuronosyltransferases (such as ritonavir), may increase the clearance of valproate. For
example, phenytoin, carbamazepine, and phenobarbital (or primidone) can double the clearance
of valproate. Thus, patients on monotherapy will generally have longer half-lives and higher
concentrations than patients receiving polytherapy with antiepilepsy drugs.
In contrast, drugs that are inhibitors of cytochrome P450 isozymes, e.g., antidepressants, may be
expected to have little effect on valproate clearance because cytochrome P450 microsomal
mediated oxidation is a relatively minor secondary metabolic pathway compared to
glucuronidation and beta-oxidation.
Because of these changes in valproate clearance, monitoring of valproate and concomitant drug
concentrations should be increased whenever enzyme inducing drugs are introduced or
withdrawn.
The following list provides information about the potential for an influence of several commonly
prescribed medications on valproate pharmacokinetics. The list is not exhaustive nor could it be,
since new interactions are continuously being reported.
Drugs For Which A Potentially Important Interaction Has Been Observed
Aspirin
A study involving the co-administration of aspirin at antipyretic doses (11 to 16 mg/kg) with
valproate to pediatric patients (n = 6) revealed a decrease in protein binding and an inhibition of
metabolism of valproate. Valproate free fraction was increased 4-fold in the presence of aspirin
compared to valproate alone. The β-oxidation pathway consisting of 2-E-valproic acid, 3-OHvalproic
acid, and 3-keto valproic acid was decreased from 25% of total metabolites excreted on
valproate alone to 8.3% in the presence of aspirin. Caution should be observed if valproate and
aspirin are to be co-administered.
Carbapenem Antibiotics
A clinically significant reduction in serum valproic acid concentration has been reported in
patients receiving carbapenem antibiotics (for example, ertapenem, imipenem, meropenem; this
is not a complete list) and may result in loss of seizure control. The mechanism of this interaction
is not well understood. Serum valproic acid concentrations should be monitored frequently after
initiating carbapenem therapy. Alternative antibacterial or anticonvulsant therapy should be
considered if serum valproic acid concentrations drop significantly or seizure control deteriorates
.
Cholestyramine
Cholestyramine, when concurrently administered with valproic acid, led to, on average, a 14%
decrease in plasma levels of valproic acid in a study conducted in 6 healthy subjects
administered Depakene (valproic acid) and cholestyramine. Delaying the administration of
cholestyramine relative to valproic acid administration by 3 hours may lessen the interaction.
Estrogen-Containing Hormonal Contraceptives
Estrogen-containing hormonal contraceptives may increase the clearance of valproate, which
may result in decreased concentration of valproate and potentially increased seizure frequency.
Prescribers should monitor serum valproate concentrations and clinical response when adding or
discontinuing estrogen containing products.
Felbamate
A study involving the co-administration of 1,200 mg/day of felbamate with valproate to patients
with epilepsy (n = 10) revealed an increase in mean valproate peak concentration by 35% (from
86 to 115 mcg/mL) compared to valproate alone. Increasing the felbamate dose to 2,400 mg/day
increased the mean valproate peak concentration to 133 mcg/mL (another 16% increase). A
decrease in valproate dosage may be necessary when felbamate therapy is initiated.
Rifampin
A study involving the administration of a single dose of valproate (7 mg/kg) 36 hours after 5
nights of daily dosing with rifampin (600 mg) revealed a 40% increase in the oral clearance of
valproate. Valproate dosage adjustment may be necessary when it is co-administered with
rifampin.
Drugs For Which Either No Interaction Or A Likely Clinically Unimportant Interaction Has Been
Observed
Antacids
A study involving the co-administration of valproate 500 mg with commonly administered
antacids (Maalox, Trisogel, and Titralac - 160 mEq doses) did not reveal any effect on the extent
of absorption of valproate.
Chlorpromazine
A study involving the administration of 100 to 300 mg/day of chlorpromazine to schizophrenic
patients already receiving valproate (200 mg BID) revealed a 15% increase in trough plasma
levels of valproate.
Haloperidol
A study involving the administration of 6 to 10 mg/day of haloperidol to schizophrenic patients
already receiving valproate (200 mg BID) revealed no significant changes in valproate trough
plasma levels.
Cimetidine and Ranitidine
Cimetidine and ranitidine do not affect the clearance of valproate.
Effects Of Valproate On Other Drugs
Valproate has been found to be a weak inhibitor of some P450 isozymes, epoxide hydrase, and
glucuronosyltransferases.
The following list provides information about the potential for an influence of valproate coadministration
on the pharmacokinetics or pharmacodynamics of several commonly prescribed
medications. The list is not exhaustive, since new interactions are continuously being reported.
Drugs For Which A Potentially Important Valproate Interaction Has Been Observed
Amitriptyline/Nortriptyline
Administration of a single oral 50 mg dose of amitriptyline to 15 normal volunteers (10 males
and 5 females) who received valproate (500 mg BID) resulted in a 21% decrease in plasma
clearance of amitriptyline and a 34% decrease in the net clearance of nortriptyline. Rare
postmarketing reports of concurrent use of valproate and amitriptyline resulting in an increased
amitriptyline level have been received. Concurrent use of valproate and amitriptyline has rarely
been associated with toxicity. Monitoring of amitriptyline levels should be considered for
patients taking valproate concomitantly with amitriptyline. Consideration should be given to
lowering the dose of amitriptyline/nortriptyline in the presence of valproate.
Carbamazepine/carbamazepine-10,11-Epoxide
Serum levels of carbamazepine (CBZ) decreased 17% while that of carbamazepine-10,11-
epoxide (CBZ-E) increased by 45% upon co-administration of valproate and CBZ to epileptic
patients.
Clonazepam
The concomitant use of valproate and clonazepam may induce absence status in patients with a
history of absence type seizures.
Diazepam
Valproate displaces diazepam from its plasma albumin binding sites and inhibits its metabolism.
Co-administration of valproate (1,500 mg daily) increased the free fraction of diazepam (10 mg)
by 90% in healthy volunteers (n = 6). Plasma clearance and volume of distribution for free
diazepam were reduced by 25% and 20%, respectively, in the presence of valproate. The
elimination half-life of diazepam remained unchanged upon addition of valproate.
Ethosuximide
Valproate inhibits the metabolism of ethosuximide. Administration of a single ethosuximide dose
of 500 mg with valproate (800 to 1,600 mg/day) to healthy volunteers (n = 6) was accompanied
by a 25% increase in elimination half-life of ethosuximide and a 15% decrease in its total
clearance as compared to ethosuximide alone. Patients receiving valproate and ethosuximide,
especially along with other anticonvulsants, should be monitored for alterations in serum
concentrations of both drugs.
Lamotrigine
In a steady-state study involving 10 healthy volunteers, the elimination half-life of lamotrigine
increased from 26 to 70 hours with valproate co-administration (a 165% increase). The dose of
lamotrigine should be reduced when co-administered with valproate. Serious skin reactions (such
as Stevens-Johnson syndrome and toxic epidermal necrolysis) have been reported with
concomitant lamotrigine and valproate administration. See lamotrigine package insert for details
on lamotrigine dosing with concomitant valproate administration.
Phenobarbital
Valproate was found to inhibit the metabolism of phenobarbital. Co-administration of valproate
(250 mg BID for 14 days) with phenobarbital to normal subjects (n = 6) resulted in a 50%
increase in half-life and a 30% decrease in plasma clearance of phenobarbital (60 mg singledose).
The fraction of phenobarbital dose excreted unchanged increased by 50% in presence of
valproate.
There is evidence for severe CNS depression, with or without significant elevations of
barbiturate or valproate serum concentrations. All patients receiving concomitant barbiturate
therapy should be closely monitored for neurological toxicity. Serum barbiturate concentrations
should be obtained, if possible, and the barbiturate dosage decreased, if appropriate.
Primidone, which is metabolized to a barbiturate, may be involved in a similar interaction with
valproate.
Phenytoin
Valproate displaces phenytoin from its plasma albumin binding sites and inhibits its hepatic
metabolism. Co-administration of valproate (400 mg TID) with phenytoin (250 mg) in normal
volunteers (n = 7) was associated with a 60% increase in the free fraction of phenytoin. Total
plasma clearance and apparent volume of distribution of phenytoin increased 30% in the
presence of valproate. Both the clearance and apparent volume of distribution of free phenytoin
were reduced by 25%.
In patients with epilepsy, there have been reports of breakthrough seizures occurring with the
combination of valproate and phenytoin. The dosage of phenytoin should be adjusted as required
by the clinical situation.
Propofol
The concomitant use of valproate and propofol may lead to increased blood levels of propofol.
Reduce the dose of propofol when co-administering with valproate. Monitor patients closely for
signs of increased sedation or cardiorespiratory depression.
Rufinamide
Based on a population pharmacokinetic analysis, rufinamide clearance was decreased by
valproate. Rufinamide concentrations were increased by <16% to 70%, dependent on
concentration of valproate (with the larger increases being seen in pediatric patients at high doses
or concentrations of valproate). Patients stabilized on rufinamide before being prescribed
valproate should begin valproate therapy at a low dose, and titrate to a clinically effective dose
. Similarly, patients on valproate should begin at a
rufinamide dose lower than 10 mg/kg per day (pediatric patients) or 400 mg per day (adults).
Tolbutamide
From in vitro experiments, the unbound fraction of tolbutamide was increased from 20% to 50%
when added to plasma samples taken from patients treated with valproate. The clinical relevance
of this displacement is unknown.
Warfarin
In an in vitro study, valproate increased the unbound fraction of warfarin by up to 32.6%. The
therapeutic relevance of this is unknown; however, coagulation tests should be monitored if
valproate therapy is instituted in patients taking anticoagulants.
Zidovudine
In six patients who were seropositive for HIV, the clearance of zidovudine (100 mg q8h) was
decreased by 38% after administration of valproate (250 or 500 mg q8h); the half-life of
zidovudine was unaffected.
Drugs For Which Either No Interaction Or A Likely Clinically Unimportant Interaction Has Been
Observed
Acetaminophen
Valproate had no effect on any of the pharmacokinetic parameters of acetaminophen when it was
concurrently administered to three epileptic patients.
Clozapine
In psychotic patients (n = 11), no interaction was observed when valproate was co-administered
with clozapine.
Lithium
Co-administration of valproate (500 mg BID) and lithium carbonate (300 mg TID) to normal
male volunteers (n = 16) had no effect on the steady-state kinetics of lithium.
Lorazepam
Concomitant administration of valproate (500 mg BID) and lorazepam (1 mg BID) in normal
male volunteers (n = 9) was accompanied by a 17% decrease in the plasma clearance of
lorazepam.
Olanzapine
No dose adjustment for olanzapine is necessary when olanzapine is administered concomitantly
with valproate. Co-administration of valproate (500 mg BID) and olanzapine (5 mg) to healthy
adults (n=10) caused 15% reduction in Cmax and 35% reduction in AUC of olanzapine.
Oral Contraceptive Steroids
Administration of a single-dose of ethinyloestradiol (50 mcg)/levonorgestrel (250 mcg) to 6
women on valproate (200 mg BID) therapy for 2 months did not reveal any pharmacokinetic
interaction.
Topiramate
Concomitant administration of valproate and topiramate has been associated with
hyperammonemia with and without encephalopathy. Concomitant administration of topiramate with valproate has
also been associated with hypothermia in patients who have tolerated either drug alone. It may be
prudent to examine blood ammonia levels in patients in whom the onset of hypothermia has been
reported.