Discontinuation of clonazepam after long-term treatment.

Frequent unwanted side effects and development of tolerance are the main disadvantages of clonazepam (CZP) in long-term treatment of epileptic patients. A review of the literature shows that CZP tolerance more often appears in severe forms of childhood epilepsy (West and Lennox-Gastaut syndromes) than in other epileptic syndromes. We prospectively studied the consequences of CZP discontinuation in 40 consecutive children with difficult-to-treat epilepsies and multiple-drug therapy. The CZP was reduced stepwise in a variable daily reduction rate (0.003-0.16 mg/kg), while serum levels of the comedication were kept unchanged. In only three children (7.5%), CZP was believed to have had some antiepileptic effect; in 30 (75%) it had been ineffective, whereas in six (15%), a decrease in seizure frequency after CZP discontinuation even suggested a negative therapeutic effect. Discontinuation symptoms, mostly in the form of a transitory exacerbation of seizure frequency, occurred in 19 children (47.5%). These children had a significantly higher CZP dose and longer duration of treatment than did children without discontinuation symptoms, but there was no difference between the two groups related to the rate of CZP discontinuance.