Clonazepam is a new benzodiazepine anticonvulsant recently approved by the Food and Drug Administration for the treatment of typical absence, infantile myoclonic, atypical absence, myoclonic, and akinetic seizures. It is rapidly absorbed by the oral route and appears to pass quickly from blood to brain. Preliminary results indicate a biological half-life of 22 to 32 hours and a therapeutic serum concentration of 5 to 50 ng/ml. Many studies report tolerance to the anticonvulsant effects with chronic administration. Major side effects of the drug are drowsiness, ataxia, and behavior changes. They tend to be dose related, occur early in the course of therapy, and may subside with chronic administration. Accordingly, the dosage is begun at a low level and increased slowly.