PT - JOURNAL ARTICLE AU - E. C. Wolters AU - D. B. Calne TI - Parkinson's disease DP - 1989 Mar 01 TA - Canadian Medical Association Journal PG - 507--514 VI - 140 IP - 5 4099 - http://www.cmaj.ca/content/140/5/507.short 4100 - http://www.cmaj.ca/content/140/5/507.full SO - CMAJ1989 Mar 01; 140 AB - In Parkinson's disease there is degeneration of neurons in the substantia nigra, with consequent depletion of the neurotransmitter dopamine. The triad of tremor, rigidity and bradykinesia is the clinical hallmark. Drugs currently used for palliative therapy fall into three categories: anticholinergic agents, dopamine precursors (levodopa combined with extracerebral decarboxylase inhibitors) and artificial dopamine agonists. It has been argued, on theoretical grounds, that some drugs slow the progress of Parkinson's disease, although no firm evidence has supported this. Treatment must be individualized, and more than one type of drug can be given concurrently after a careful build-up in dosage. We review the adverse effects of various drugs and consider new developments such as slow-release preparations, selective D-1 and D-2 agonists and transplants of dopaminergic cells into the brain. The treatment of Parkinson's disease can be demanding, rewarding and sometimes frustrating, but it remains a most challenging exercise in pharmacotherapy.