Differing Patterns of Diurnal Variation and Impact of Antacids on Levodopa Pharmacokinetics in Patients with Parkinson's Disease

Purpose: Levodopa plasma concentrations are variable, and drug‒drug interactions affect the pharmacokinetics of levodopa. However, examination of the diurnal variation in levodopa plasma concentrations of patients with Parkinson's disease (PD) is insufficient. The effects of antacids on the pharmacokinetics of levodopa remain unclear. Thus, we examined the diurnal variation in the pharmacokinetics of levodopa in patients with PD to clarify the types of variability. The effects of antacids (magnesium oxide) on the pharmacokinetics of levodopa were also investigated.