Colitis microscópica y exposición a fármacos: una revisión crítica

Abstract

Microscopic colitis (MC) comprises 2 fundamental entities (lymphocytic colitis and collagenous colitis) defined by chronic or recurrent watery diarrhea, normal colonoscopy and characteristic histopathological features. The exposure of the colonic mucosa at different luminal antigens, including different drugs, has been involved in the still poor understood pathophysiology of MC. Thus, the relationship between the development of MC after drug exposure has been the subject of research for more than 2 decades, mainly based on observational studies, including case reports and case series, case-control studies, and data on drug prescriptions. Among others, proton-pump inhibitors, nonsteroidal antiinflammatory drugs, selective inhibitors of serotonin reuptake, beta-blockers and statins, have been linked to the onset of MC, but all these drugs are also recognized as a frequent cause of drug-associated diarrhea.

At present we have no universally accepted criteria for establishing cause-effect relationships in adverse drug reactions, although several methods have provide us with different levels of likelihood. Thus, the existence of a high probability of MC occurrence as an adverse effect to a specific drug has been shown only in individual cases by using chronological (exposure, effect of withdrawal and relapse with re-exposure) and semiological criteria. Although case-control studies have repeatedly shown significant associations between drug exposure and MC, variability in their designs, including reference populations used and the criteria considered in defining drug exposure, requires a detailed analysis. This article critically examines the complex relationship between drugs, diarrhea and MC, to conclude that a likely cause-effect relationship has only been described for few drugs and in individual cases of MC.