Some Medications Negatively Affect the Gut Microbiome... for Years
A large-scale study conducted by researchers at the Institute of Genomics at the University of Tartu in Estonia revealed that certain medications can negatively affect the composition and effectiveness of the community of beneficial microbes living in the human gut for an extended period after discontinuation, which may partially explain the differences in individuals’ microbiomes years after treatment.
The researchers analyzed stool samples and medical prescription records of more than 2,500 participants in the Estonian Biobank and found that most of the studied medications were associated with differences in the gut microbiome, and these differences remained detectable for a large number of drugs even years after use had ceased. These lasting effects were not limited to antibiotics, which are already known to disrupt the balance of gut bacteria, but also included antidepressants, beta-blockers (used to treat high blood pressure and certain heart conditions), proton pump inhibitors (typically prescribed for acid reflux), and benzodiazepines (used to treat anxiety).
The study’s lead researcher, Dr. Oliver Asmuss, stated, “Most microbiome studies consider only current medications, whereas our results show that prior drug use may be a crucial factor in explaining individual differences in the microbiome.” Benzodiazepines were particularly surprising, as their association with microbiome changes was comparable to that of broad-spectrum antibiotics.
The study also found that drugs belonging to the same pharmacological class do not necessarily affect the microbiome in the same way; for example, diazepam and alprazolam, despite belonging to the same class, differed in their impact on gut bacteria, indicating the need to study each drug individually rather than generalizing findings across a drug class. Follow-up samples, collected from a smaller group of participants, confirmed the persistent effects associated with proton pump inhibitors, selective serotonin reuptake inhibitors (SSRIs), and antibiotics such as penicillin combinations and macrolides.
Professor Elin Org, the study’s principal supervisor, added, “This is a comprehensive, systematic assessment of the long-term effects of medications on the microbiome based on real-world medical records, and we hope it will encourage researchers and physicians to take medication history into account when interpreting microbiome data.”
Among the most prominent drug classes found to have a long-term impact on the gut microbiome are:
