WARNING: Serious dermatologic reactions associated with HLA-B∗1502 allele (mostly Asian ancestry). Aplastic anemia and agranulocytosis have been reported.
INDICATIONS AND USE: Anticonvulsant. Treatment of partial (especially complex partial), primary generalized tonic-clonic seizures and mixed partial or generalized seizures.
ACTIONS: Decrease synaptic transmission, limits influx of sodium ions across cell membrane.
ADVERSE EFFECTS: Nausea, vomiting, leukopenia, thrombocytopenia, aplastic anemia and agranulocytosis, congestive heart failure (CHF), heart block, dystonia, drowsiness, and behavioral changes, syndrome of inappropriate antidiuretic hormone secretion (SIADH), hyponatremia, hepatitis and cholestasis, rash and Stevens-Johnson syndrome, urine retention, azotemia, oliguria, and anuria. Monitor complete blood cell count (CBC), liver function, and urinalysis; perform periodic eye examination. Do not discontinue abruptly because seizures may result in epileptic patients.
PHARMACOLOGY: Metabolized in liver by cytochrome P450 3A4. Induces liver enzymes and increases its own metabolism. Half-life in neonates is 8–28 hours. Therapeutic range is 4–12 mcg/mL.
COMMENTS: Avoid switching between Tegretol and generic carbamazepine; changes in serum concentration and seizure activity may result; monitor serum concentrations. Interactions are numerous. Erythromycin, isoniazid, and cimetidine may inhibit hepatic metabolism of carbamazepine, resulting in increased carbamazepine serum concentrations. Concurrent phenobarbital may lower carbamazepine serum levels. Carbamazepine may induce metabolism of warfarin, phenytoin, theophylline, benzodiazepines, and corticosteroids.