Drug-induced parkinsonism in the aged. Recognition and prevention.

Drug-induced Parkinsonism is a frequent adverse effect of numerous drugs interfering with dopamine function at the basal ganglionic level. It accounts for 4% of all patients with Parkinsonism seen in neurology clinics. Pharmacological agents implicated in the production of this disorder have a wide range of applications in medicine, beyond the treatment of psychiatric illnesses. Antipsychotics, substituted benzamides and calcium channel blockers are the drugs most commonly involved. The aged population is at an increased risk of drug-induced Parkinsonism due to intrinsic factors and because they often receive multiple drugs, including those from self-medication. Lack of knowledge in the medical profession of the potential hazards involved in the use of certain drugs plays a contributory role in the development of drug-induced Parkinsonism. Physicians should be always alert in order to detect, as early as possible, the presence of extrapyramidal symptoms in patients exposed to medications with antidopaminergic properties. Whenever possible, withdrawal of the medication will help resolve symptoms; complete remission takes place within 6 to 18 months in the majority of patients. The use of anti-Parkinsonian drugs is only advisable if the symptomatology is disabling. The best available treatment is prevention.