Idiopathic Parkinsonism treated with an extracerebral decarboxylase inhibitor in combination with levodopa.

The clinical actions of levodopa in Parkinsonism, given with and without an extracerebral decarboxylase in hibitor, L-alpha-methyldopahydrazine, were compared. Twenty-one patients were investigated in a "double-blind cross-over" study, administering levodopa in maximum tolerated dosage. L-Alpha-methyldopahydrazine failed to augment the overall therapeutic actions of levodopa but it consistently alleviated nausea. It is concluded that L-alpha-methyldopahydrazine will prove useful in the management of some Parkinsonian patients who have difficulty in taking levodopa alone.