Levodopa and gastric emptying

[aspergerian]

The influence of levodopa on gastric emptying in man.

D R Robertson, A G Renwick, N D Wood, N Cross, B S Macklin, J S Fleming, D G Waller, and C F George.

Pharmacol. 1990 Jan; 29(1): 47–53.

PMCID: PMC1380060

PMID: 2404503

Abstract

1. Simultaneous radioisotopic (99Tc-DTPA) gastric emptying measurements and paracetamol pharmacokinetic studies were performed in eight healthy male volunteers with and without levodopa (125 mg orally). 2. In the absence of levodopa gamma camera imaging showed rapid mono or biexponential emptying in all subjects and the plasma concentration-time curves for paracetamol displayed a single major peak. 3. In the presence of levodopa the time to 90% emptying was prolonged from 32 +/- 24 min to 81 +/- 20 min (P less than 0.01). Gastric emptying was interrupted by a plateau phase in six subjects and this pattern of emptying was associated with double peaks in the plasma concentration-time curves of both levodopa and paracetamol. The time to the end of the plateau phase of emptying correlated with the time to the trough plasma concentrations of paracetamol and levodopa. 4. There was excellent agreement between the plasma concentration-time curves of levodopa and paracetamol, i.e. time to initial peak, r = 0.946, P less than 0.001; time to trough concentration r = 0.943, P less than 0.01; time to second peak r = 0.974, P less than 0.001. 5. The results indicate that levodopa inhibits gastric emptying and thus influences its own absorption. Temporary inhibition of gastric emptying by levodopa (or a metabolite) is the cause of the multiple plasma peaks commonly observed following oral levodopa.

ncbi.nlm.nih.gov/pmc/articl...

Also:

ncbi.nlm.nih.gov/pmc/articl...

And:

Gastric emptying, postprandial blood pressure, glycaemia and splanchnic flow in Parkinson’s disease.

Laurence G Trahair, Thomas E Kimber, [...], and Karen L Jones.

2016.

ncbi.nlm.nih.gov/pmc/articl...

Evaluation of gastric emptying in familial and sporadic Parkinson disease.

Anna Krygowska-Wajs, William P. Cheshire, Jr., [...], and Anna Sowa-Staszczak.

2014? 2009?

ncbi.nlm.nih.gov/pmc/articl...

Also:

ncbi.nlm.nih.gov/pmc/articl...

And:

Gastroparesis and Parkinson's disease: a systematic review.

Heetun ZS, et al. Parkinsonism Relat Disord. 2012.

ncbi.nlm.nih.gov/m/pubmed/2...

Some of the gastrointestinal (GI) symptoms commonly experienced by patients with Parkinson's disease (PD) have been attributed to gastroparesis; however, the precise prevalence and relevance of gastric emptying delay in PD is unclear. The definition of gastroparesis varies; currently the most widely accepted definition (from the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Clinical Research Consortium) is the presence of appropriate symptoms (including nausea, retching, vomiting, stomach fullness, and inability to finish a meal) for ≥ 12 weeks, together with delayed gastric emptying on scintigraphy and the absence of any obstructive lesions on upper GI endoscopy. In PD patients, gastroparesis has the potential to affect nutrition and quality of life, as well as the absorption of PD medications, including L-dopa. This reduced absorption of L-dopa has implications for the control of the PD motor symptoms for which it is administered. We performed a systematic review of the literature on gastroparesis in PD with the aim of developing an evidence-based approach to its management. Based on this review, we conclude that while gastric emptying has been reported to be frequently delayed in PD, the existing data do not permit definitive conclusions concerning its true prevalence, relationship to the underlying disease process, relevance to PD management, or the optimal therapy of related GI symptoms. Further study of these important issues is, therefore, required.

PMID 22209346

[Kevin51]

"levodopa inhibits gastric emptying and thus influences its own absorption." !!!

[Hidden]

Very interesting. When reading the small print on some medications you may find references to Use in Specific Populations and describe differences in Geriatric or Gender and Patients with Early or Advanced Parkinson’s Disease. The small print also advises of drug interactions which make some drugs more or less effective or increase systemic exposure by as much as 33 to 37%. This is way way over my head, but it tells me that we need to pay attention to studies. You would think the studies would break down the results with similar attention to the “specific populations.” Thank you for this information.

[aspergerian in reply to Hidden]

CKingPs,

Thank you for clarifying an important aspect.