Prescription history leaves lasting imprint on gut bacteria, study finds

A study of over 2,500 Estonian Biobank participants found that many common drugs, including antidepressants, beta-blockers, and acid reducers, are linked to distinct gut microbiome changes that persist for years after stopping. The effects were not limited to antibiotics, suggesting past medication use may be a major factor in shaping current microbial communities. Researchers say this highlights the need to consider prescription history in microbiome studies.

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The study drew on stool samples and prescription records from over 2,500 Estonian Biobank participants. Researchers found that most medications examined were tied to gut microbiome differences, and for many drugs these differences remained detectable years after discontinuation. Beyond antibiotics, the lasting effects included antidepressants, beta-blockers, proton pump inhibitors, and benzodiazepines.

A notable finding was that benzodiazepines showed microbiome associations comparable to broad-spectrum antibiotics. Additionally, drugs within the same class did not always affect microbes similarly—diazepam and alprazolam differed in their apparent impact. Follow-up samples from a smaller group helped researchers observe changes when participants started or stopped medications, suggesting individual drugs