Central anticholinergic actions of doxepin in rabbits

Neuropharmacological effects of doxepin were studied in rabbits to reveal fundamental actions which might explain its clinical efficacy. The results indicate that central effects of this compound are similar to those reported for atropine and the tricyclic antidepressants. In this regard, doxepin produced mydriasis and EEG synchrony without producing overt signs of sleep. It inhibited in a dose-related manner the EEG activation produced by physostigmine. It inhibited the EEG, but not behavioral, effects of methamphetamine. Doxepin enhanced some of the behavioral effects of methamphetamine, as does atropine.