Augmenting the action of levodopa.

Various pharmacological approaches to potentiate the therapeutic actions of levodopa and reduce side-effects are reviewed. Of currently available drugs, anticholinergic agents and amantadine have been studied extensively. Inhibition of extracerebral decarboxylase appears to be the most promising new area of investigation, though experience is at present limited. Other methods discussed include inhibition of enzymes catechol-O-methyl transferase, monoamine oxidase and dopamine beta hydroxylase. Conflicting evidence on 3-O-methyldopa is discussed.