Vigabatrin in the treatment of complex partial seizures.

We report the effect of vigabatrin on seizure frequency in 13 severely drug-resistant patients with intractable complex partial seizures (CPS) with or without secondary generalization. Patients were followed for a 3-month period before vigabatrin administration to establish a 'baseline'. Six patients became seizure free for 2-3 weeks immediately after starting vigabatrin. In seven patients a transient (4-6 weeks) increase in seizures above baseline occurred, which was attenuated by vigabatrin dose increments. After 3 months, the mean baseline CPS frequency was reduced from 7.75 +/- 1.18 (median 8, range 2.6-16) to 2.77 +/- 0.7 (median 1, range 0-7). At 6 months a > 50% improvement remained in seven patients. After 12 or more months CPS frequency returned to baseline in four patients, improved (by 25-62.5%) in four and deteriorated in three. One patient who was seizure free lost control at 16 months. Other effects were drowsiness (3), weight increase (3), diarrhoea (1), depression (2) and mood elevation (2). Four patients discontinued vigabatrin; one because of severe depression, three owing to lack of efficacy. Three patients have undergone and two are awaiting neurosurgery for their epilepsy. Thus, CPS frequency progressively deteriorated toward baseline in all patients, however, secondary generalizations were abolished in four and reduced in two.