Canemes

Overdose

Signs and symptoms of overdosage are an extension of the psychotomimetic and physiologic effects of Canemes.

To obtain up-to-date information about the treatment of overdose, a good recredit is your certified Regional Poison Control Center. Telephone numbers of certified poison control centers are listed in the Physicians' Desk Reference (PDR). In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in your patient.

Overdosage may be considered to have occurred, even at prescribed dosages, if disturbing psychiatric symptoms are present. In these cases, the patient should be observed in a quiet environment and supportive measures, including reassurance, should be used. Subsequent doses should be withheld until patients have returned to their baseline mental status; routine dosing may then be resumed if clinically indicated. In such instances, a lower initiating dose is suggested. In controlled clinical trials, alterations in mental status related to the use of Canemes resolved within 72 hours without specific medical therapy.

In overdose settings, attention should be paid to vital signs, since both hypertension and hypotension have been known to occur; tachycardia and orthostatic hypotension were most commonly reported.

No cases of overdosage with more than 10 mg/day of nabilone were reported during clinical trials. Signs and symptoms that would be expected to occur in large overdose situations are psychotic episodes, including hallucinations, anxiety reactions, respiratory depression, and coma.

If psychotic episodes occur, the patient should be managed conservatively, if possible. For moderate psychotic episodes and anxiety reactions, verbal support and comforting may be sufficient. In more severe cases, antipsychotic drugs may be useful; however, the utility of antipsychotic drugs in cannabinoid psychosis has not been systematically evaluated. Support for their use is drawn from limited experience using antipsychotic agents to manage cannabis overdoses. Because of the potential for drug-drug interactions (e.g., additive CNS depressant effects due to nabilone and chlorpromazine), such patients should be closely monitored.

Protect the patient's airway and support ventilation and perfusion. Meticulously monitor and maintain, within acceptable limits, the patient's vital signs, blood gases, serum electrolytes, as well as other laboratory values and physical assessments. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which, in many cases, is more effective than emesis or lavage; consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Safeguard the patient's airway when employing gastric emptying or charcoal.

The use of forced diuresis, peritoneal dialysis, hemodialysis, charcoal hemoperfusion, or cholestyramine has not been reported. In the presence of normal renal function, most of a dose of nabilone is eliminated through the biliary system.

Treatment for respiratory depression and comatose state consists in symptomatic and supportive therapy. Particular attention should be paid to the occurrence of hypothermia. If the patient becomes hypotensive, consider fluids, inotropes, and/or vasopressors.

The estimated oral median lethal dose in female mice is between 1,000 and 2,000 mg/kg; in the female rat, it is greater than 2,000 mg/kg, (See CLINICAL PHARMACOLOGY).

Contraindications

Canemes is contraindicated in any patient who has a history of hypersensitivity to any cannabinoid.

Undesirable effects

To report SUSPECTED ADVERSE REACTIONS, contact Meda Pharmaceuticals Inc. at 1-800-723-1400 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

During controlled clinical trials of Canemes, virtually all patients experienced at least one adverse reaction. The most commonly encountered events were drowsiness, vertigo, dry mouth, euphoria (feeling “high”), ataxia, headache, and concentration difficulties.

Accurate estimates of the incidence of adverse events associated with the use of any drug are difficult to obtain. Estimates are influenced by factors such as drug dose, detection technique, setting, and physician judgments, among others. Consequently, the tables presented below are presented solely to indicate the relative frequency of adverse events reported in representative controlled clinical studies conducted to evaluate the safety and efficacy of Canemes under relatively similar conditions of use. The figures cited cannot be used to predict precisely the incidence of untoward events in the course of usual medical practice, in which patient characteristics and other factors may differ from those that prevailed in the clinical trials. These incidence figures also cannot be compared with those obtained from other clinical studies involving related drug products because each group of drug trials is conducted under a different set of conditions.

Finally, it is important to emphasize that these tabulations do not reflect the relative severity and/or clinical importance of the adverse events. A better perspective on the serious adverse events associated with the use of Canemes is provided in the WARNINGS AND PRECAUTIONS sections.

The following tables list in order of decreasing frequency the adverse reactions encountered by a substantial proportion of patients treated with Canemes participating in representative controlled clinical trials.

Incidence of Adverse Reactions in Placebo-Controlled Studies

Incidence of Adverse Reactions in Active-Controlled Studies

Adverse Reactions by Body System—The following list of adverse events is organized by decreasing frequency within body systems for patients treated with Canemes in controlled clinical trials. All events are listed regardless of causality assessment.

Blood and Hematopoietic—Anemia

Cardiovascular—Orthostatic hypotension, hypotension, tachycardia, syncope, palpitation, flushing, hypertension, arrhythmia, and cerebral vascular accident.

Eye and Ear—Vision disturbance, ear tightness, eye irritation, eye dryness, equilibrium dysfunction, tinnitus, eye disorder, amblyopia, eye swelling, eyelid diseases, pupil dilation, photophobia, and visual field defect.

Gastrointestinal—Dry mouth, nausea, anorexia, vomiting, diarrhea, abdominal pain, constipation, aphthous ulcer, mouth irritation, gastritis, and dyspepsia.

Genitourinary—Increased urination, decreased urination, hot flashes, urinary retention, and frequency of micturition.

Infection—Bacterial infection

Metabolic and Endocrine—Thirst

Musculoskeletal—Muscle pain, back pain, neck pain, joint pain, and unspecified pain.

Nervous System—Drowsiness, vertigo, ataxia, decreased concentration, sedation, hallucinations, paresthesia, tremor, memory disturbance, perception disturbance, convulsions, dystonia, numbness, and akathisia.

Psychiatric—Euphoria (feeling “high”), sleep disturbance, depression, confusion, disorientation, anxiety, depersonalization syndrome, speech disorder, abnormal dreams, insomnia, mood swings, inebriated feeling, toxic psychosis, paranoia, apathy, thought disorder, withdrawal, panic disorder, phobic neurosis, emotional disorder, and hyperactivity.

Respiratory—Dyspnea, pharyngitis, nasal congestion, sinus headache, thick tongue, dry throat, dry nose, wheezing, nosebleed, cough, voice change, and chest pain.

Skin and Appendages—Anhidrosis, photosensitivity, pruritus, rash, and allergic reactions.

Miscellaneous and Ill-Defined Conditions—Headache, fatigue, lightheadedness, coordination disturbance, asthesia, dysphoria, dizziness, taste change, excessive appetite, chills, excessive sweating, nervousness, malaise, postural dizziness, twitch, irritability, fever, inhibited walking, unconsciousness, hypotonia, and impaired urination.

Postmarketing Adverse Reactions—Canemes has been marketed internationally since 1982. The following adverse reactions listed in order of decreasing frequency by body system have been reported since Canemes has been marketed. All events are listed regardless of causality assessment.

Blood and Hematopoietic—Leukopenia

Cardiovascular—Hypotension and tachycardia

Eye and Ear—Visual disturbances

Gastrointestinal—Dry mouth, nausea, vomiting, and constipation

Nervous System—Hallucinations, CNS depression, CNS stimulation, ataxia, stupor, vertigo, convulsion, and circumoral paresthesia

Psychiatric—Somnolence, confusion, euphoria, depression, dysphoria, depersonalization, anxiety, psychosis, and emotional lability

Miscellaneous and Ill-Defined Conditions—Dizziness, headache, insomnia, abnormal thinking, chest pain, lack of effect, and face edema

Canemes, a synthetic cannabinoid pharmacologically related to Cannabis sativa L. (Marijuana; (delta-9-THC) is a highly abusable substance. Canemes is controlled under Schedule II (CII) of the Controlled Substances Act. Prescriptions for Canemes should be limited to the amount necessary for a single cycle of chemotherapy (i.e., a few days). Canemes may produce subjective side effects which may be interpreted as a euphoria or marijuana-like “high” at therapeutic doses.

It is not known what proportion of individuals exposed chronically to Canemes or other cannabinoids will develop either psychological or physical dependence. Long term use of these compounds has, however, been associated with disorders of motivation, judgment, and cognition. It is not clear, though, if this is a manifestation of the underlying personalities of chronic users of this class of drugs or if cannabinoids are directly responsible for these effects. An abstinence syndrome has been reported following discontinuation of delta-9-THC at high doses of 200 mg per day for 12 to 16 consecutive days. The acute phase was characterized by psychic distress, insomnia, and signs of autonomic hyperactivity (sweating, rhinorrhea, loose stools, hiccups). A protracted abstinence phase may have occurred in subjects who reported sleep disturbances for several weeks after delta-9-THC discontinuation.

Canemes may produce subjective side effects that may be interpreted as a euphoria or marijuana-like “high” at therapeutic doses. Canemes was shown to be qualitatively and quantitatively similar to delta-9-THC in the production of cannabis-like effects, thus demonstrating that Canemes has a high potential for abuse.

Preclinical studies performed in both dogs and monkeys demonstrated that Canemes was cannabinoid-like. As with delta-9-THC, tolerance develops rapidly to the pharmacological effects in both the dog and the monkey. Cross-tolerance between Canemes and delta-9-THC was demonstrated in the monkey.

The physical dependence capacity of Canemes is unknown at this time. Patients who participated in clinical trials of up to 5 days' duration evidenced no withdrawal symptoms on cessation of dosing.

Therapeutic indications

Canemes capsules are indicated for the treatment of the nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional antiemetic treatments. This restriction is required because a substantial proportion of any group of patients treated with Canemes can be expected to experience disturbing psychotomimetic reactions not observed with other antiemetic agents.

Because of its potential to alter the mental state, Canemes is intended for use under circumstances that permit close supervision of the patient by a responsible individual particularly during initial use of Canemes and during dose adjustments.

Canemes contains nabilone, which is controlled in Schedule II of the Controlled Substances Act. Schedule II substances have a high potential for abuse. Prescriptions for Canemes should be limited to the amount necessary for a single cycle of chemotherapy (i.e., a few days).

Canemes capsules are not intended to be used on as needed basis or as a first antiemetic product prescribed for a patient.

As with all controlled drugs, prescribers should monitor patients receiving nabilone for signs of excessive use, abuse and misuse. Patients who may be at increased risk for substance abuse include those with a personal or family history of substance abuse (including drug or alcohol abuse) or mental illness.

Pharmacodynamic properties

Canemes (nabilone) is an orally active synthetic cannabinoid which, like other cannabinoids, has complex effects on the central nervous system (CNS). It has been suggested that the antiemetic effect of nabilone is caused by interaction with the cannabinoid receptor system, i.e., the CB (1) receptor, which has been discovered in neural tissues.

Canemes, a synthetic cannabinoid, has the potential to be abused and to produce psychological dependence. Canemes has complex effects on the central nervous system. Its effects on the mental state (i.e., “inner mental life”) are similar to those of cannabis. Subjects given Canemes may experience changes in mood (euphoria, detachment, depression, anxiety, panic, paranoia), decrements in cognitive performance and memory, a decreased ability to control drives and impulses, and alterations in the experience of reality (e.g., distortions in the perception of objects and the sense of time, hallucinations). These phenomena appear to be more common when larger doses of Canemes are administered; however, a full-blown picture of psychosis (psychotic organic brain syndrome) may occur in patients receiving doses within the lower portion of the therapeutic range.

Data on the chronic use of Canemes are not available; experience with cannabis suggests that chronic use of cannabinoids may be associated with a variety of untoward effects on motivation, cognition, judgment, as well as other mental status changes. Whether these phenomena reflect the underlying character of individuals chronically abusing cannabis or are a result of the use of cannabis is not known.

The simultaneous use of Canemes and alcohol or barbiturates may produce additive depressive effects on central nervous system function. Possible changes in mood and other adverse behavioral effects may occur in patients receiving Canemes. Patients should remain under supervision of a responsible adult while using Canemes.

Canemes has central nervous system activity. It produces relaxation, drowsiness, and euphoria in the recommended dosage range. Tolerance to these effects develops rapidly and is readily reversible.

In addition to effects on the mental state, Canemes has several systemic actions; most prominent are dry mouth and hypotension. Canemes has been observed to elevate supine and standing heart rates and to cause supine and orthostatic hypotension. In clinical studies, oral administration of 2 mg of Canemes did produce some decrease in airway resistance in normal controls but had no effect in patients with asthma. No other nontherapeutic effects of clinical significance due to Canemes have been reported.

Pharmacokinetic properties

Canemes (nabilone) appears to be completely absorbed from the human gastrointestinal tract when administered orally. Following oral administration of a 2 mg dose of radiolabeled nabilone, peak plasma concentrations of approximately 2 ng/mL nabilone and 10 ng equivalents/mL total radioactivity are achieved within 2.0 hours. The plasma half-life (T½) values for nabilone and total radioactivity of identified and unidentified metabolites are about 2 and 35 hours, respectively. The initial rapid disappearance of radioactivity represents uptake and distribution of nabilone into tissue and the slower phase elimination by metabolism and excretion. The apparent volume of distribution of nabilone is about 12.5 L/kg.

Nabilone exhibits dose linearity within its therapeutic range. Clinical data suggests that the intake of food does not significantly affect either the rate or extent of absorption.

Metabolism of nabilone is extensive and several metabolites have been identified. Precise information concerning the metabolites that may accumulate is not available. The relative activities of the metabolites and the parent drug have not been established. There are at least two metabolic pathways involved in the biotransformation of nabilone. A minor pathway is initiated by the stereospecific enzymatic reduction of the 9-keto moiety of nabilone to produce the isomeric carbinol metabolite. The peak concentrations of nabilone and its carbinol metabolites are comparable, but their combined exposures in plasma do not account for more than 20% of that of total radioactivity. Secondly, a metabolite of nabilone in feces has been identified as a diol formed by reduction of the 9-keto group plus oxidation at the penultimate carbon of the dimethylheptyl side chain. In addition, there is evidence of extensive metabolism of Canemes by multiple P450 enzyme isoforms. In vitro P450 inhibition studies using human liver microsomes showed that nabilone did not significantly inhibit CYP1A2, 2A6, 2C19, 2D6, and 3A4 (using midazolam and nifedipine as substrates). Nabilone had a weak inhibitory effect on CYP 2E1 and 3A4 (testosterone; IC50 > 50 μM) and had a moderate inhibitory effect on CYP2C8 and 2C9 (IC50 > 10 μM). However, in clinical use, the very low nabilone plasma concentration is unlikely to interfere with the P450-mediated degradation of co-administered drugs. Chronic oral administration of 1 mg t.i.d. for 14 days to 3 subjects gave no indication there was any significant accumulation of nabilone. Available evidence suggests that one or more of the metabolites has a terminal elimination half-life that exceeds that of nabilone. Consequently, in repeated use, the metabolites may accumulate at concentrations in excess of the parent drug.

The route and rate of the elimination of nabilone and its metabolites are similar to those observed with other cannabinoids, including delta-9-THC (dronabinol). When nabilone is administered intravenously, the drug and its metabolites are eliminated mainly in the feces (approximately 67%) and to a lesser extent in the urine (approximately 22%) within 7 days. Of the 67% recovered from the feces, 5% corresponded to the parent compound and 16% to its carbinol metabolite. Following oral administration about 60% of nabilone and its metabolites were recovered in the feces and about 24% in urine. Therefore, it appears that the major excretory pathway is the biliary system.

The effects of age, gender, hepatic dysfunction, and renal insufficiency on the metabolism and elimination of nabilone have not been determined.

The pharmacokinetic profile of Canemes has not been investigated in either pediatric (See PRECAUTIONS, Pediatric Use) or geriatric patients (See PRECAUTIONS, Geriatric Use).

Name of the medicinal product

Qualitative and quantitative composition

Special warnings and precautions for use

• The effects of Canemes may persist for a variable and unpredictable period of time following its oral administration. Adverse psychiatric reactions can persist for 48 to 72 hours following cessation of treatment.
• Canemes has the potential to affect the CNS, which might manifest itself in dizziness, drowsiness, euphoria “high”, ataxia, anxiety, disorientation, depression, hallucinations and psychosis.
• Canemes can cause tachycardia and orthostatic hypotension.
• Because of individual variation in response and tolerance to the effects of Canemes, patients should remain under supervision of a responsible adult especially during initial use of Canemes and during dose adjustments.
• Patients receiving treatment with Canemes should be specifically warned not to drive, operate machinery, or engage in any hazardous activity while receiving Canemes.
• Canemes should not be taken with alcohol, sedatives, hypnotics, or other psychoactive substances because these substances can potentiate the central nervous system effects of nabilone.

The benefit/risk ratio of Canemes use should be carefully evaluated in patients with the following medical conditions because of individual variation in response and tolerance to the effects of Canemes.

• Since Canemes can elevate supine and standing heart rates and cause postural hypotension, it should be used with caution in the elderly, and in patients with hypertension or heart disease.
• Canemes should also be used with caution in patients with current or previous psychiatric disorders, (including manic depressive illness, depression, and schizophrenia) as the symptoms of these disease states may be unmasked by the use of cannabinoids.
• Canemes should be used with caution in individuals receiving concomitant therapy with sedatives, hypnotics, or other psychoactive drugs because of the potential for additive or synergistic CNS effects.
• Canemes should be used with caution in patients with a history of substance abuse, including alcohol abuse or dependence and marijuana use, since Canemes contains a similar active compound to marijuana.
• The safety aspects of the effects of hepatic and renal impairment have not been investigated.
• Nabilone is purportedly highly bound to plasma proteins and undergoes extensive first pass hepatic metabolism. Those properties have the potential to lead to drug-drug interactions affecting the pharmacokinetics of similar behaving co-administered drugs or of Canemes itself.
• The effects of QT prolongation potential by Canemes have not been determined.
• Canemes should be used with caution in pregnant patients, nursing mothers, or pediatric patients because it has not been studied in these patient populations.

No long-term studies in animals have been performed to evaluate the carcinogenic potential of nabilone.

Nabilone was not genotoxic in the Ames test, the rat hepatocyte unscheduled DNA synthesis (UDS) test, the Chinese hamster bone marrow cell sister chromatid exchange (SCE) test, the male rat dominant lethal tests nor the rat micronucleus test.

Dietary administration of nabilone up to 4 mg/kg/day (about 6 times the recommended maximum human dose based on body surface area) was found to have no effect on fertility and reproductive performance of male and female rats.

Pregnancy Category C

Teratology studies conducted in pregnant rats at doses up to 12 mg/kg/day (about 16 times the human dose on a body surface area basis) and in pregnant rabbits at doses up to 3.3 mg/kg/day (about 9 times the human dose on a body surface area basis) did not disclose any evidence for a teratogenic potential of nabilone. However, there was dose related developmental toxicity in both species as evidenced by increases in embryo lethality, fetal resorptions, decreased fetal weights and pregnancy disruptions. In rats, postnatal developmental toxicity was also observed. There are no adequate and well-controlled studies in pregnant women. Because animal studies cannot rule out the possibility of harm, Canemes should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

It is not known whether this drug is excreted in breast milk. Because many drugs including some cannabinoids are excreted in breast milk it is not recommended that Canemes be given to nursing mothers.

Safety and effectiveness have not been established in patients younger than 18 years of age. Caution is recommended in prescribing Canemes to children because of psychoactive effects.

Clinical studies of Canemes did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Canemes should be used with caution in elderly patients aged 65 and over because they are generally more sensitive to the psychoactive effects of drugs and Canemes can elevate supine and standing heart rates and cause postural hypotension.

Dosage (Posology) and method of administration

The usual adult dosage is 1 or 2 mg 2 times a day. On the day of chemotherapy, the initial dose should be given 1 to 3 hours before the chemotherapeutic agent is administered. To minimize side effects, it is recommended that the lower starting dose be used and that the dose be increased as necessary. A dose of 1 or 2 mg the night before may be useful. The maximum recommended daily dose is 6 mg given in divided doses 3 times a day.

Canemes may be administered 2 or 3 times a day during the entire course of each cycle of chemotherapy and, if needed, for 48 hours after the last dose of each cycle of chemotherapy.