Inner Workings: Microbiota munch on medications, causing big effects on drug activity. pnas.
Levodopa’s side effects and benefits vary widely among patients. Those puzzling disparities, it turns out, have a lot to do with the microbes in their guts...
Balskus and her colleagues found that although carbodopa works on human enzymes, it does not inhibit bacterial decarboxylase. In fact, the bacterial enzyme acts on the drug in the intestines before it crosses the blood–brain barrier, triggering problematic symptoms (1).