• Controlled-release carbidopa levodopa 50/200 (SINEMET CR) and standard carbidopa/levodopa (SINEMET 25/100) were compared in a double-blind, six-month, crossover study involving 21 patients with chronic Parkinson's disease and motor response fluctuations. Daily dosage frequency was significantly reduced with SINEMET CR compared with SINEMET 25/100, while the daily amount of levodopa required with SINEMET CR was significantly greater. No significant differences in disability ratings, motor response fluctuations, or safety were detected during double-blind conditions. In the open-label, dose-finding phase of the study, SINEMET CR was superior to standard SINEMET 25/100 in patient ratings of percent "on" time (good motor function), clinical assessments of motor function, and activities of daily living. This finding resulted from a depreciation of the value of the "old drug" rather than an overestimation of the value of the experimental drug. This double-blind study also suggested that elderly male patients with Parkinson's disease derived the greatest benefit from SINEMET CR.
Hutton JT, Morris JL, Román GC, Imke SC, Elias JW. Treatment of Chronic Parkinson's Disease With Controlled-Release Carbidopa/Levodopa. Arch Neurol. 1988;45(8):861–864. doi:10.1001/archneur.1988.00520320047014