Objective: We introduced a new way of prescribing carbidopa/levodopa extended-release (ER) capsule – combining use of immediate-release (IR) tablets. This retrospective clinical study was designed to investigate factors associated with successful conversion.

Background: Carbidopa/levodopa extended-release capsule is a new levodopa formula for Parkinson’s disease which, according to its pharmacokinetics, provides a more steady serum level to increase ON and reduced OFF time. However, financial concern is the major issue leading to medication withdrawal. Taiwan National Health Institute imposes a limitation of maximal 4 capsules per day. Thus we proposed a new prescription method: combination use of carbidopa/levodopa immediate-release table and extended-release capsule and analyzed factors of successful conversion.

Method: We enrolled patients converted into extended-release capsules with or without other dopaminergic medication use. Successful conversion was defined as consecutive use of capsules without dose changes for at least 3 months. Clinical data were collected for analysis.

Results: Forty-four patients were recruited, 34 with successful and 10 with unsuccessful conversion. There was no significant difference between 2 groups in age, gender, disease duration, Hohn & Yahr stage, gait, total levodopa equivalent dose, levodopa dose, medication frequency, or kick-in duration. Factors associated with successful conversion included lower BMI (23.8±4 v.s 29.4±, p=0.02), presence of dyskinesia (77.8% v.s 33.3%, p=0.04), and shorter medication effect (2.7±0.5 v.s 3.4±0.6 hours, p=0.04).

In the successful conversion group, there was increased ON time of 2.4±1 hours and decreased OFF time of 2.1±1.5 hours. The average conversion dose was 1.56 times of the previous immediate-release levodopa with IR/ER ratio of 0.73±0.38. Younger disease onset patients preferred higher IR/ER ratio (R²=0.19, p =0.017) Most common unsuccessful conversion reason was poor ON or no ON, followed by side effect of dizziness.

Conclusion: Partial conversion with combination use of immediate and extended-release carbidopa/levodopa can achieve similar results of improving motor fluctuation. This method provides a more economical way of prescribing extended-release capsule.

« Back to 2024 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/combining-carbidopa-levodopa-extended-release-capsules-and-immediate-release-tablets-crucial-factors-of-this-economical-prescription/