Parkinson's disease: a pharmacological update.

The primary biochemical defect in Parkinsonism is dopamine depletion. Anticholinergics (except in the elderly) and amantadine are useful in treating early symptomatic disease. L-dopa remains the most effective drug, but experience has led to more modest use due to its late complications, particularly dyskinesias. Bromocriptine, a dopamine agonist, is relatively effective, but when it should be used is undecided. Beta-blockers may control tremor. Treatment should be tailored to each patient, and focus on functional motor ability. Dyskinesias and neuropsychiatric complications are the major limiting factors with most of these drugs. Several drugs are under investigation.