No evidence that drugs trigger microscopic colitis in older people
There is a perception that common drugs such as ibuprofen and SSRI preparations can trigger the intestinal disease microscopic colitis (MC). However, a new study from Karolinska Institutet and Harvard Medical School suggests that this is not the case – meaning that patients with MC do not need to stop taking important medications.
Microscopic colitis (MC) is a chronic inflammatory bowel disease that severely impairs quality of life. MC accounts for over 30 per cent of all cases of chronic diarrhoea in people over 65, and its prevalence is increasing worldwide. Although little is known about the causes of MC, previous studies have suggested that several common medications may trigger the disease, including certain anti-inflammatory drugs (NSAIDs) used to treat fever and pain, such as ibuprofen, as well as certain blood pressure medications, cholesterol-lowering drugs and selective serotonin reuptake inhibitors (SSRIs), a medication often prescribed for depression.
2.8 million people in the study
However, according to a new study published in Annals of Internal Medicine based on 2.8 million people aged 65 and older in Sweden, most of these drugs are not associated with an increased risk of MC.
"Our study showed that, contrary to previous beliefs, it is unlikely that drugs are the trigger for microscopic colitis. Healthcare providers should carefully weigh the benefits of these drugs against the very low likelihood that they cause microscopic colitis," said first author Hamed Khalili, a researcher at Harvard Medical School and a physician at the Crohn's and Colitis Centre at Massachusetts General Hospital in Boston.
However, the researchers did find that people prescribed SSRIs had a 0.04 per cent higher risk of developing MC. But the study showed that people prescribed SSRIs were also more likely to undergo colonoscopy, which is necessary to diagnose MC.
"Our analyses suggest that previous findings showing a link between drugs and microscopic colitis are likely due to these patients being examined to a greater extent. This could potentially also explain why the link to SSRIs is still seen," says Jonas F. Ludvigsson, professor at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, and paediatrician at Örebro University Hospital.
See the study for funding and any conflicts of interest.
The text is based on a press release from Mass General Brigham Hospital in Massachusetts, USA.
Publication
“Medications and risk of microscopic colitis: A nationwide study of older adults in Sweden”, Hamed Khalili, Emma E. McGee, Prasanna K Challa, Bjorn Roelstraete, Kristina Johnell, Sebastian Schneeweiss, Jonas W. Wastesson, Jonas F Ludvigsson, Annals of Internal Medicine, online June 30, 2025, doi: 10.7326/ANNALS-25-00268