Levodopa is the main oral treatment for Parkinson’s disease, and doctors often prescribe catechol-O-methyltransferase inhibitors, or COMT inhibitors, to increase how much levodopa reaches the brain.
A team from Yale School of Medicine reported in Nature Microbiology that COMT inhibitors can have an unexpected effect. The researchers, led by postdoctoral associate Andrew Verdegaal in the lab of Andrew Goodman, found that these drugs have antibacterial properties and can change the composition of the gut microbiome.
Because COMT inhibitors kill some susceptible bacteria, other species can expand. Higher levels of Enterococcus faecalis matter because this bacterium carries an enzyme that metabolizes levodopa in the gut, preventing some of the drug from crossing to the brain and reducing its benefit.
The findings back earlier work linking E. faecalis to lower levodopa efficacy. The study notes the interaction acts through the gut microbiome rather than the liver, and it urges clinicians and researchers to consider microbiome effects on co-prescribed drugs. The research received support from the National Institutes of Health and Yale University.
Difficult words
- levodopa — medicine taken by mouth for Parkinson's symptoms
- inhibitor — drug or substance that reduces another chemical's actioninhibitors, COMT inhibitors
- microbiome — all the microorganisms living in one body area
- antibacterial — able to kill or stop growth of bacteria
- metabolize — to change a drug or food inside the bodymetabolizes
- efficacy — how well a treatment produces the wanted result
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could changes in the gut microbiome affect the way other medicines work for a patient?
- Why is it important for doctors to think about effects on the microbiome when they prescribe more than one drug?
- What further studies or tests would you suggest to check how common these drug–microbiome interactions are?
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