Will Subcutaneous Levodopa Stick?

Levodopa is universally accepted as the most effective symptomatic therapy for Parkinson disease (PD). Several studies have documented the dramatic effectiveness of levodopa for motor and nonmotor symptoms of PD.1 Despite its effectiveness, levodopa has shortcomings, including (1) a short elimination half-life that leads to the need for several doses per day, long-acting formulations, or adjuvant medications to extend action1; (2) erratic absorption by an active transport system for neutral amino acids located in the jejunum that is susceptible to variations in gastric emptying and dietary protein intake2,3; and (3) narrowing of the therapeutic window as the disease progresses leading to motor fluctuations including wearing off and peak-dose dyskinesias.1