Physostigmine. Its use in acute anticholinergic syndrome with antidepressant and antiparkinson drugs.

We reviewed the use of physostigmine in the diagnosis and management of acute toxic psychosis due to drugs with anticholinergic properties. The syndrome of agitation and toxic confusional psychosis associated with peripheral signs of cholinergic blockade is produced by several plant toxins, antispasmodics, ophthalmic preparations, and certain proprietary sedatives, as well as antiparkinson medications, antidepressants, and some antipsychotic drugs. Physostigmine, uniquely among the available reversible anticholinesterase agents, can pass the blood-brain barrier to exert central as well as peripheral cholinomimetic actions to reverse this syndrome. Psychiatrists should make more use of this safe, specific, rapid, and effective treatment for anticholinergic drug toxicity, and should particularly be alert to reversible anticholinergic brain syndromes associated with antidepressants and antiparkinson medications, and even with antipsychotic medications.