Adverse reactions to antiepileptic drugs: a multicenter survey of clinical practice. Collaborative Group for Epidemiology of Epilepsy.

A multicenter survey of adverse drug reactions (ADR) to anticonvulsants was conducted in 15 university and hospital departments, including six epilepsy centers in Italy. Five hundred and nine patients undergoing chronic anticonvulsant therapy (greater than 3 months) were admitted to the study. Details of the main characteristics of the underlying disease, drug schedules, and ADR (including date of onset, type, involved tissue or organ, severity, duration, acceptability by the patient, clinical significance, referral pattern, and clinical implications) were provided. One or more ADR were recorded in 157 cases (31%), with a wide range of referrals among centers (6-79%). Of the 232 recorded ADR, 109 were definite, 84 were possible, and 26 were doubtful. In 54.5% of the cases ADR were reported by the patient, 52.5% were clinically important, 49.5% were permanent, and 67% were tolerable. In 53% of patients having ADR no decisions had been taken. Plasma levels of anticonvulsants were determined in 47% of cases and for 49% of the prescribed drugs. The proportion of cases with ADR was 22% in patients receiving monotherapy, 34.2% in patients treated with two drugs, and 44.4% in patients receiving three or more drugs. Thirty-three percent of patients taking phenytoin as the only drug had ADR as compared with 23, 15, and 12% of patients treated with phenobarbital, carbamazepine, and sodium valproate or depamide. Somnolence was the commonest complaint (51 cases), followed by gingival hyperplasia (34 cases), nystagmus (23 cases), and ataxia (16 cases). These findings provide a real-life profile of the ADR to anticonvulsants, with inclusion of the factors likely to influence the behavior of the practicing physicians.(ABSTRACT TRUNCATED AT 250 WORDS)