The treatment of tricyclic antidepressant overdose with repeated charcoal.

Activated charcoal given repeatedly through a nasogastric tube to three patients in coma from amitriptyline overdose greatly accelerated tricyclic elimination: the apparent half-life fell below 10 hours for each patient to as low as 4 hours. This contrasts with extended half-lives for amitriptyline elimination averaging 36.8 hours and regularly over 60 hours previously reported for overdoses treated without repeated charcoal. The enterohepatic recirculation of amitriptyline and nortriptyline appears to be a major influence on keeping their blood levels up. In one case, intravenous diazepam inhibited tricyclic elimination.