Phenytoin toxicity due to interaction with clobazam.
The benzodiazepine antiepileptic drug clobazam can be added to existing AED treatment, usually without clinical toxicity. We report 3 patients in whom the addition of clobazam led within several weeks to clinically obvious phenytoin (PHT) intoxication in patients who had been taking maximum tolerable PHT doses. Symptoms and high PHT levels resolved with lowering the PHT dose. Clobazam and norclobazam levels were not elevated. This interaction is probably related to interference with hepatic degradation of PHT. Clinicians should be aware of possible PHT intoxication in patients starting clobazam.
Zifkin
B
B
Département des Sciences Neurologiques, Hôpital du Sacré-Coeur de Montréal, Université de Montréal, PQ, Canada.
Sherwin
A
A
Andermann
F
F
D000328:Adult; D014151:Anti-Anxiety Agents; D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use; D001569:Benzodiazepines; D001570:Benzodiazepinones / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid; D000078306:Clobazam; D004347:Drug Interactions; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D010672:Phenytoin / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D012640:Seizures / Q000188:drug therapy
D014151:Anti-Anxiety Agents; D000927:Anticonvulsants; D001570:Benzodiazepinones; D001569:Benzodiazepines; D000078306:Clobazam; D010672:Phenytoin