title: Interactions of L-dopa and amantadine in patients with Parkinsonism.
abstract: Twenty-seven patients with Parkinson's disease participated in a double-blind crossover trial of L-dopa and amantadine. Each drug was given for six weeks, and six weeks were allowed to elapse between the two periods of treatment. Marked improvement occurred in patients given L-dopa first, whereas no clinical effect was observed in those patients treated first with amantadine. L-dopa was less beneficial to patients who had previously received amantadine, whereas amantadine became effective in patients who had previously taken L-dopa. The effect of pre-treatment with one drug on the therapeutic effectiveness of the other drug is reflected in changes of homovanillic acid levels in the cerebrospinal fluid.
mesh_terms: D000547:Amantadine / Q000008:administration & dosage / Q000627:therapeutic use*; D004295:Dihydroxyphenylalanine / Q000008:administration & dosage / Q000627:therapeutic use*; D004347:Drug Interactions; D005069:Evaluation Studies as Topic; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid; D006801:Humans; D008297:Male; D008875:Middle Aged; D009127:Muscle Rigidity / Q000188:drug therapy; D009132:Muscles / Q000187:drug effects; D010300:Parkinson Disease / Q000134:cerebrospinal fluid / Q000188:drug therapy*; D014202:Tremor / Q000188:drug therapy
chemical_list: D004295:Dihydroxyphenylalanine; D000547:Amantadine; D006719:Homovanillic Acid