Reversal of Antiparkinsonian Drug Toxicity by Physostigmine: A Controlled Study

Three female schizophrenic patients receiving a combination of psychotropic agents, including the antiparkinsonian agent benztropine mesylate, developed the central anticholinergic syndrome, consisting of hallucinations, anxiety, short-term memory loss, disorientation, and agitation. These symptoms responded dramatically to physostigmine salicylate administered intramuscularly; they were unaffected by placebo injection given on a double-blind basis. In patients receiving multiple psychotropic drugs, evaluation of whether the patient is acting confused because of the combined central anticholinergic properties of these drugs is important. When identified, this syndrome can usually be treated by reduction of the dose of the anticholinergic agents or in special instances by the use of the cholinomimetic agent physostigmine.