Overdose
The oral LD50 of spironolactone is greater
than 1000 mg/kg in mice, rats, and rabbits. The oral LD50 of
hydrochlorothiazide is greater than 10 g/kg in both mice and rats.
Acute overdosage of spironolactone may be manifested by
drowsiness, mental confusion, maculopapular or erythematous rash, nausea,
vomiting, dizziness, or diarrhea. Rarely, instances of hyponatremia,
hyperkalemia (less commonly seen with ALDACTAZIDE because the
hydrochlorothiazide component tends to produce hypokalemia), or hepatic coma
may occur in patients with severe liver disease, but these are unlikely due to
acute overdosage.
However, because ALDACTAZIDE contains both spironolactone
and hydrochlorothiazide, the toxic effects may be intensified, and signs of
thiazide overdosage may be present. These include electrolyte imbalance such as
hypokalemia and/or hyponatremia. The potassium-sparing action of spironolactone
may predominate and hyperkalemia may occur, especially in patients with
impaired renal function. BUN determinations have been reported to rise
transiently with hydrochlorothiazide. There may be CNS depression with lethargy
or even coma.
Treatment
 Induce vomiting or evacuate the stomach by lavage. There
is no specific antidote. Treatment is supportive to maintain hydration,
electrolyte balance, and vital functions.
Patients who have renal impairment may develop
spironolactone-induced hyperkalemia. In such cases, ALDACTAZIDE should be
discontinued immediately. With severe hyperkalemia, the clinical situation
dictates the procedures to be employed. These include the intravenous
administration of calcium chloride solution, sodium bicarbonate solution,
and/or the oral or parenteral administration of glucose with a rapid-acting
insulin preparation. These are temporary measures to be repeated as required.
Cationic exchange resins such as sodium polystyrene sulfonate may be orally or
rectally administered. Persistent hyperkalemia may require dialysis.
Undesirable effects
The following adverse reactions have been reported and,
within each category (body system), are listed in order of decreasing severity.
Hydrochlorothiazide
Body as a whole: Weakness.
Cardiovascular: Hypotension including orthostatic
hypotension (may be aggravated by alcohol, barbiturates, narcotics, or
antihypertensive drugs).
Digestive: Pancreatitis, jaundice (intrahepatic
cholestatic jaundice), diarrhea, vomiting, sialoadenitis, cramping,
constipation, gastric irritation, nausea, anorexia.
Eye Disorders: acute myopia and acute angle closure
glaucoma (see WARNINGS). Hematologic: Aplastic anemia, agranulocytosis,
leukopenia, hemolytic anemia, thrombocytopenia.
Hypersensitivity: Anaphylactic reactions,
necrotizing angitis (vasculitis and cutaneous vasculitis), respiratory distress
including pneumonitis and pulmonary edema, photosensitivity, fever, urticaria,
rash, purpura.
Metabolic: Electrolyte imbalance (see PRECAUTIONS),
hyperglycemia, glycosuria, hyperuricemia.
Musculoskeletal: Muscle spasm.
Nervous system/psychiatric: Vertigo, paresthesias,
dizziness, headache, restlessness.
Renal: Renal failure, renal dysfunction,
interstitial nephritis (see WARNINGS).
Skin: Erythema multiforme, pruritus.
Special senses: Transient blurred vision,
xanthopsia.
Spironolactone
Digestive: Gastric bleeding, ulceration,
gastritis, diarrhea and cramping, nausea, vomiting.
Reproductive: Gynecomastia (see PRECAUTIONS),
inability to achieve or maintain erection, irregular menses or amenorrhea,
postmenopausal bleeding, breast pain. Carcinoma of the breast has been reported
in patients taking spironolactone but a cause and effect relationship has not
been established.
Hematologic: Leukopenia (including
agranulocytosis), thrombocytopenia.
Hypersensitivity: Fever, urticaria, maculopapular
or erythematous cutaneous eruptions, anaphylactic reactions, vasculitis.
Metabolism: Hyperkalemia, electrolyte disturbances
(see WARNINGS and PRECAUTIONS).
Musculoskeletal: Leg cramps.
Nervous system/psychiatric: Lethargy, mental
confusion, ataxia, dizziness, headache, drowsiness.
Liver/biliary: A very few cases of mixed
cholestatic/hepatocellular toxicity, with one reported fatality, have been
reported with spironolactone administration.
Renal: Renal dysfunction (including renal
failure).
Skin: Stevens-Johnson Syndrome (SJS), toxic
epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms
(DRESS), alopecia, pruritus.
Fertility, pregnancy and lactation
Teratogenic effects
Pregnancy Category C. Hydrochlorothiazide: Studies
in which hydrochlorothiazide was orally administered to pregnant mice and rats
during their respective periods of major organogenesis at doses up to 3000 and
1000 mg hydrochlorothiazide/kg, respectively, provided no evidence of harm to
the fetus. There are, however, no adequate and well-controlled studies in
pregnant women.
Spironolactone
Teratology studies with spironolactone have been carried
out in mice and rabbits at doses of up to 20 mg/kg/day. On a body surface area
basis, this dose in the mouse is substantially below the maximum recommended
human dose and, in the rabbit, approximates the maximum recommended human dose.
No teratogenic or other embryo-toxic effects were observed in mice, but the 20
mg/kg dose caused an increased rate of resorption and a lower number of live
fetuses in rabbits. Because of its antiandrogenic activity and the requirement
of testosterone for male morphogenesis, spironolactone may have the potential
for adversely affecting sex differentiation of the male during embryogenesis.
When administered to rats at 200 mg/kg/day between gestation days 13 and 21
(late embryogenesis and fetal development), feminization of male fetuses was
observed. Offspring exposed during late pregnancy to 50 and 100 mg/kg/day doses
of spironolactone exhibited changes in the reproductive tract including
dose-dependent decreases in weights of the ventral prostate and seminal vesicle
in males, ovaries and uteri that were enlarged in females, and other
indications of endocrine dysfunction, that persisted into adulthood. There are
no adequate and well-controlled studies with ALDACTAZIDE in pregnant women.
Spironolactone has known endocrine effects in animals including progestational
and antiandrogenic effects. The antiandrogenic effects can result in apparent
estrogenic side effects in humans, such as gynecomastia. Therefore, the use of
ALDACTAZIDE in pregnant women requires that the anticipated benefit be weighed
against the possible hazards to the fetus.
Non-teratogenic effects
Spironolactone or its metabolites may, and
hydrochlorothiazide does, cross the placental barrier and appear in cord blood.
Therefore, the use of ALDACTAZIDE in pregnant women requires that the
anticipated benefit be weighed against possible hazards to the fetus. The
hazards include fetal or neonatal jaundice, thrombocytopenia, and possibly
other adverse reactions that have occurred in adults.