Effect of controlled-release carbidopa/levodopa on motor performance in advanced Parkinson's disease

Twenty parkinsonian patients were treated with controlled-release carbidopa/levodopa (Sinemet CR). All were affected by therapeutic response fluctuations related to the timing of drug administration. The daily dosage after 1 year, 766 mg +/- 250 mg, was increased by 23% compared with standard Sinemet dosage, without additional secondary effects. Parkinsonian scores improved by 43%; the prolongation of "on" periods was 63%. Nevertheless, 7 patients withdrew from this study during the 1st month of treatment. Only 1 withdrew due to an adverse reaction to the formulation, a recurrence of hallucinations. The progressive effect of the 1st morning dose and the often unpredictable time at which the product first takes effect were found to be frustrating for the other patients who withdrew. We believe that this disappointment can be avoided by giving new patients the controlled-release formulation from the start of therapy.