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Updated: Apr 27, 2026
Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson's Disease
Published on: October 14, 2021
Liquid melevodopa versus standard levodopa in patients with Parkinson disease and small intestinal bacterial
Alfonso Fasano1, Francesco Bove, Maurizio Gabrielli
1*Movement Disorders Center, TWH, UHN, Division of Neurology, University of Toronto, Toronto, Ontario, Canada; †Departments of Neurology, and ‡Internal Medicine, Catholic University of Sacred Heart, Gemelli University Hospital, Rome, Italy; §Department of Pharmacology, Catholic University of Sacred Heart, Rome, Italy; and ||Medical Direction, Chiesi Farmaceutici, Parma, Italy.
Objectives:
Patients with Parkinson disease exhibit a highly increased prevalence of small intestinal bacterial overgrowth (SIBO), which has been also associated with the severity of motor fluctuations. Aim of this study was to test the efficacy of liquid levodopa with higher bioavailability in patients with SIBO.
Methods:
Thirty-three patients with Parkinson disease underwent both lactulose and glucose breath tests to assess the presence of SIBO. A urea breath test was performed to assess the presence of a concomitant Helicobacter pylori infection. Patients were challenged with 250 mg of levodopa and 314 mg of levodopa methylester. Drug challenges were performed on different days and at baseline and 1 month after SIBO eradication. During the tests, the motor condition and the plasma levodopa concentrations were evaluated.
Results:
At baseline, the onset of motor benefit was significantly shorter after melevodopa than after standard levodopa, as confirmed by the latency to motor on condition and t max (time to the on condition, 28.8±11.5 vs 55.5±40.2 minutes; P=0.0004; and t max, 28.2±9.7 vs 50.0±11.0 minutes; P=0.002). The duration of the on time or area under the curve was not significantly different. The underlying gastrointestinal condition did not influence these results.
Conclusions:
The reduction of the latency to the on condition in the absence of a reduction of the on duration is a promising feature of melevodopa because this effect would increase the total daily on duration. Future studies that evaluate the usefulness of melevodopa beyond the acute challenge (eg, using motor diaries) in patients with gastrointestinal infections are warranted.
Insights
Liquid levodopa (melevodopa) significantly reduced the time to motor benefit in Parkinson disease patients with small intestinal bacterial overgrowth (SIBO). This offers a promising approach to improve daily motor function in this patient group.
Area of Science:
- Neurology
- Gastroenterology
- Pharmacology
Background:
- Parkinson disease (PD) patients frequently have small intestinal bacterial overgrowth (SIBO).
- SIBO severity correlates with motor fluctuations in PD.
- Previous treatments have not optimally addressed SIBO-related motor symptoms.
Purpose of the Study:
- To evaluate the efficacy of liquid levodopa (melevodopa) in Parkinson disease patients with SIBO.
- To assess if melevodopa improves motor response compared to standard levodopa in this cohort.
Main Methods:
- Thirty-three PD patients underwent breath tests to diagnose SIBO and Helicobacter pylori infection.
- Patients received challenges with standard levodopa and melevodopa at baseline and after SIBO eradication.
- Motor response and plasma levodopa concentrations were monitored.
Main Results:
- Melevodopa significantly reduced the time to motor benefit (latency to 'on' and t max) compared to standard levodopa.
- No significant difference was observed in the duration of 'on' time.
- Gastrointestinal status did not impact these findings.
Conclusions:
- Melevodopa's ability to shorten motor response latency is a key advantage.
- This may lead to increased total daily 'on' time for PD patients with SIBO.
- Further research is needed to confirm melevodopa's long-term benefits in patients with gastrointestinal issues.
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