Olmesartan-Induced Enteropathy: Case Reports and Insights From FDA Adverse Event Reporting System (FAERS)

Olmesartan, an angiotensin II receptor blocker (ARB) approved in 2002, is used to treat hypertension, either alone or with other antihypertensive drugs. It has been frequently associated with sprue-like enteropathy, while few cases of colitis have been reported. Differentiating between sprue-like enteropathy and colitis is of clinical concern, since just the first condition is a well-documented adverse event of olmesartan. Diagnosis of these occurrences is difficult, as symptoms are unspecific namely diarrhoea, weight loss, fatigue, nausea, and abdominal discomfort, with laboratory findings showing anaemia, electrolyte imbalances, and vitamin deficiencies. Here, we report two cases of patients in treatment for hypertension with olmesartan in association with hydrochlorothiazide and amlodipine, who developed sprue-like enteropathy and colitis, respectively. We then conducted a disproportionality analysis of cases retrieved from the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) to assess the association level between these conditions and olmesartan. We found a strong association between olmesartan and sprue-like enteropathy (ROR 8499.53 (95% CI: 8402.05 - 16383.99)). Olmesartan resulted to be associated also with colitis (ROR 2.56 (95% CI: 2.28 - 2.88)). In light of the diagnostic challenges posed by nonspecific symptoms, these findings underscore the importance of distinguishing between the two conditions in patients exposed to olmesartan, to improve the spectrum of knowledge.