Treating motor fluctuations with controlled-release levodopa preparations.

A major problem in the long-term treatment of Parkinson's disease with chronic, intermittent levodopa therapy is fluctuations in motor response. Both peripheral and central pharmacokinetic properties of levodopa are important in determining the duration of response. The "wearing-off" phenomenon or "end-of-dose" deterioration is related directly to the level of plasma levodopa. Therefore, a principal strategy for the treatment of motor fluctuations has been the attempt to prolong levodopa plasma levels with the use of long-acting, controlled-release levodopa preparations. This paper reviews the available data on the two compounds that are commercially available: benserazide-levodopa hydrodynamically balanced system (Madopar HBS) and controlled-release carbidopa-levodopa (Sinemet CR).