Anticholinergic drug abuse and misuse - Epidemiology and therapeutic implications

Abuse of the centrally acting anticholinergic agents is a phenomenon occasionally reported in the medical literature. Anticholinergics, most often used in psychiatry to treat antipsychotic-induced extrapyramidal symptoms, are also used by some patients for their mood altering and psychedelic effects. The changes in sensorium can range from mild euphoria and increased sociability to hallucinations and toxic psychosis. In this article, we have reviewed 110 cases of reported anticholinergic abuse and identified 3 distinct groups of abusers: (i) those individuals who have no valid medical need for the medication and consume it only for its mind-altering effects; (ii) those with a valid indication for the use of anticholinergics who also abuse the agents for their mind-altering effects; and (iii) those who have an appropriate medical indication for the agents and appear to be using anticholinergics to relieve chronic or subclinical extrapyramidal symptoms, depression or negative schizophrenic symptoms. True abusers (i.e. those individuals in the first 2 groups) can be recognised because they feign extrapyramidal symptoms, repeatedly 'lose' their medications or request unnecessary dose increases. In order to reduce the risk of abuse, exposure to anticholinergics should be minimised in patients at risk. Patients who are reluctant to have their anticholinergics discontinued should be carefully evaluated to identify potential risks and benefits of continued use before prolonged therapy is instituted. Anticholinergics should not be abruptly discontinued, but instead tapered over a 2-week period in patients receiving high doses or long term treatment.