Carbamazepine substitution in severe partial epilepsy: implication of autoinduction of metabolism.

Established partial seizures are often refractory to treatment and many patients receive polypharmacy. An attempt was made to improve seizure control with the substitution of carbamazepine (CBZ) for existing treatment in 7 consecutive unremitting cases of partial epilepsy referred by their physicians as 'intractable'. This produced a significant improvement in control of partial (P less than 0.02) and secondary generalized (P less than 0.01) seizures, with 5 patients experiencing a 50% or greater reduction in seizure frequency. A single patient suffered a generalized seizure during the period of changeover. In 3 cases auto-induction of CBZ metabolism resulted in temporary loss of seizure control which was restored by an increase in dose. A policy of planned substitution of CBZ in partial epilepsy previously regarded as intractable may be successful in selected patients. The possible deleterious effect of CBZ auto-induction should be anticipated.