Reduction of two-drug therapy in intractable epilepsy.

The effects of reducing two-drug treatment to single-drug therapy were studied prospectively in 36 patients with intractable complex partial seizures. In 30 patients (83%) this was possible without an increase in seizure frequency. In six patients (17%) the number of seizures was higher during single-drug therapy. The slow transfer was not complicated by unwanted withdrawal effects. The plasma concentration of the single drug was raised if necessary until clinical drug toxicity was observed. An improvement in seizure control was surprisingly noted in 13 patients (36%). In two patients seizures were completely controlled. In one patient a seizure reduction of 87% was observed. The number of patients with clinical side effects was similar during two-drug and single-drug therapy. The number of side effects was lower during single-drug therapy. Reduction of polypharmacy may be beneficial for patients with intractable epilepsy.