Physostigmine for post-operative somnolence after diazepam-nitrous oxide anaesthesia

The antidotal effect of physostigmine in a dose of 1 mg and 2 mg was investigated in 44 patients after diazepam-nitrous oxide anaesthesia. The degree of recovery was estimated using the Bender Motor Gestalt test, the post-operative recovery scores, the changes in hand force, and the cerebral function monitor (CFM) trace. Diazepam plasma levels were also determined. The improvement in the patients' alertness assessed by psychomotoric tests and the CFM trace was significant, but the recovery of the vital functions measured by the recovery scores (PARS) was marginal. Thus the indications for physostigmine in the treatment of postoperative somnolence induced by diazepam-nitrous oxide are relative and only in grave oversedation with diazepam can physostigmine be recommended as an antidote.