Highlights of the North American and European experiences.
Two large, randomized, double-blind, placebo-controlled multicenter studies, one North American and one European, examined the efficacy and safety of 300 and 600 mg/day tolcapone in similar populations of patients (n = 379) with Parkinson's disease currently taking levodopa and experiencing motor fluctuations. Change in "on-off" function was the most important end-point assessment. The two studies found similar results. The percentage of "on" time improved significantly and "off" time was reduced. Daily levodopa dosage requirements decreased significantly. The most common and significant adverse event was increased dyskinesia; hallucinations were not frequently encountered.