A Review of Levodopa Formulations for the Treatment of Parkinson's Disease Available in the United States.

Purpose : The safety and efficacy of levodopa formulations are evaluated to inform clinical decision making for the treatment of Parkinson's disease. Summary : Levodopa is a cornerstone of treatment for Parkinson's disease due to its proven efficacy. Although many patients can initially be managed using immediate release tablets, as their disease progresses they often require escalating doses as well as more frequent dosing to prevent wearing off effects. Additionally, patients who experience time in the off state may struggle with the delay between medication administration and onset of action. Therefore, to increase patient convenience as well as to enhance the pharmacokinetic profile of the levodopa, several other formulations have been developed. Levodopa coformulated with carbidopa is supplied as immediate release tablets, oral disintegrating tablets, controlled release tablets, extended release capsules, and a continuous enteral solution. Additionally, there is a levodopa inhalation powder available. As a result of their different absorption profiles, each formulation has unique safety and efficacy attributes. Consequently, while this expansion of levodopa formulations has substantially increased treatment options for patients, it has also increased the complexity of medical decision making for patients, providers, and health systems alike. Conclusion : Knowledge of the different pharmacokinetic, safety and efficacy profiles of the available levodopa formulations is critical for the effective management of Parkinson's disease on both the individual patient and population levels.