Session Information
Date: Thursday, June 8, 2017
Session Title: Parkinson’s Disease: Clinical Trials, Pharmacology And Treatment
Session Time: 1:15pm-2:45pm
Location: Exhibit Hall C
Objective: The levodopa tablet is prone to dissolve in acidic conditions. We investigated whether gastric acid suppressants (histamine-2 receptor antagonists or proton pump inhibitors) and antacids (magnesium oxide) influenced the pharmacokinetics of levodopa in patients with Parkinson’s disease (PD).
Background: The rate of levodopa absorption depends on various factors, such as the rate of gastric emptying, dietary protein content, and gastric pH. After oral administration, levodopa dissolves readily in acidic conditions and is absorbed from the proximal small intestine via the large neutral amino acid transporter. Therefore, it was suspected that the pharmacokinetics of levodopa is reduced by the co-administration of gastric acid suppressants and/or antacids.
Methods: We have measured levodopa plasma concentration of PD patients in clinical practice. Data of levodopa concentrations in PD patients who had taken a levodopa/carbidopa (100/10mg) tablet, three times a day after meals were selected for this study. The data of levodopa concentrations at every two hours from morning until evening were available
Results: A total of 102 PD patients (50 males and 52 females) were eligible. Thirty-six of 102 subjects took gastric acid suppressants and/or antacids, and 66 subjects took neither. The mean ± SD of levodopa concentration at each time point in gastric acid suppressants/antacids (+) group was 0.46 ± 1.43 μM (8 am), 3.12 ± 2.17 μM (10 am), 3.29 ± 2.10 μM (12 pm), 5.18 ± 3.00 μM (2 pm), 3.96 ± 2.68 μM (4 pm), 2.48 ± 2.23 μM (6 pm), 4.84 ± 3.58 μM (8 pm), and 3.41 ± 1.81 μM (10 pm). That in gastric acid suppressants/antacids (-) group was 0.58μM ± 1.74 (8 am), 2.89 ± 2.05μM (10 am), 3.27 ± 2.08μM (12 pm), 4.84 ± 2.54μM (2 pm), 3.84 ± 2.95μM (4 pm), 2.59 ± 2.50μM (6 pm), 4.45 ± 3.20μM (8 pm), and 3.27 ± 1.97μM (10 pm). There was no significant difference in the concentrations of levodopa between the two groups.
Conclusions: Co-administration of gastric acid suppressants and antacids has a low impact on levodopa plasma concentration in PD patients.
To cite this abstract in AMA style:
M. Nagai, M. Kubo, H. Iwaki, R. Ando, M. Nomoto. The impact of gastric acid suppressants and antacids on levodopa plasma concentration in patients with Parkinson’s disease [abstract]. Mov Disord. 2017; 32 (suppl 2). https://www.mdsabstracts.org/abstract/the-impact-of-gastric-acid-suppressants-and-antacids-on-levodopa-plasma-concentration-in-patients-with-parkinsons-disease/. Accessed June 14, 2025.« Back to 2017 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/the-impact-of-gastric-acid-suppressants-and-antacids-on-levodopa-plasma-concentration-in-patients-with-parkinsons-disease/