We have known for quite some time that certain medications affect the quality and quantity of gut bacteria. Antibiotics are well-known to affect the composition of the gut microbiome. Less widely known classes of medications that impact GI tract flora are acid-reducing medications, such as proton pump inhibitors (PPIs), and pro-motility agents like laxatives.
The scale of impact, however, is becoming more understood and was recently discussed at the UEG (United European Gastroenterology) annual meeting in Barcelona, Spain. Arnau Vich Vila, MSc, of the University Medical Center Groningen, and his colleagues studied over 1800 fecal samples looking at differences between medication users and non-users. The study showed that seven drug categories were significantly associated with changes in intestinal flora.
Some of the medications implicated in being associated with these changes include metformin and other anti-diabetic medications, oral steroids, certain oral contraceptives, and SSRI antidepressants.
It is important to note that this research is preliminary and is not yet published in a peer-reviewed journal. However, the expansion of research in this area should begin to help us understand the long-term side effect profiles of some of these medications as well as the role that the gut microbiome plays in our health and wellness. Judicious use of prescription and non-prescription medications continues to be an important topic for many reasons, now including this one.