Control of on/off phenomenon by continuous intravenous infusion of levodopa.

In 10 parkinsonian patients with severe, chaotic clinical response fluctuations, oral levodopa treatment was replaced by continuous intravenous infusion of levodopa (with orally administered benserazide). Four patients were also given levodopa infusions in addition to their usual oral treatment. All patients remained continuously mobile and ambulant during the infusions. Side effects were minimal, except in two patients with diphasic dyskinesias whose abnormal movements were consistently suppressed by a further increase in the rate of levodopa administration, only to return after an interval. If a soluble nonacidic dopamine replacement drug can be developed for continuous subcutaneous infusion, "brittle" parkinsonians may be chronically controlled by portable, minipump technology.