The site of absorption matters: Small bowel dysmotility and levodopa pharmacokinetics in Parkinson's disease

Plain language summary Looking Past the Stomach to the Small Intestine to Explain Unreliable Parkinson's Medication Absorption People with Parkinson's Disease (PD) rely on the medication levodopa to move well, but over time it often works unpredictably. Doctors usually blame the stomach, which can empty too slowly in Parkinson's, a condition called gastroparesis. However, levodopa is absorbed not in the stomach but one step further along, in the small intestine. In this letter we argue that slow movement through the small intestine, which standard stomach tests cannot detect, may be the real cause. One author had a normal stomach test but a very slow small intestine. The small intestine deserves far more attention when medication fails.