Fundamentals of carbamazepine use in neuropsychiatry.

Carbamazepine, mainly used as an anticonvulsant but also used for trigeminal neuralgias and other neuralgic pains, is now being used experimentally for affective disorders, nonresponsive psychoses, and dyscontrol. However, carbamazepine dosage must be carefully monitored because low initial doses are equivalent to higher later doses, and the drug's addition to a regimen of other drugs may increase carbamazepine's serum levels. Given alone to a pharmacologically naive inpatient, initial dosage of carbamazepine 200 mg/day can be increased by 100 mg every day or every second day; an outpatient can have the dosage increased by 100 mg every third day. Serum levels and side effects should be monitored. White cell counts usually decrease about 25%, but the decrease is not clinically related to the very rare occurrence of agranulocytosis. A side effect of concern is hepatic toxicity, but few such cases have been reported. The most common side effect is allergic rash, which occurs in about 5% of all patients receiving carbamazepine; antihistamines sometimes bring about a remission of the rash. Generic carbamazepine may cause more problems than Tegretol.