Olmesartan as an uncommon cause of enteropathy

<title>Abstract</title> Diarrhoea is the cardinal symptom of multiple pathologies in the digestive system, with multiple aetiopathogenesis. Chronic causes include pathologies such as coeliac disease, the main cause of villous atrophy in the small intestine. However, diarrhoea can also appear as an adverse reaction to drugs, sometimes with a pathophysiological basis in non-celiac enteropathy, causing malabsorptive syndromes. Angiotensin II receptor antagonist antihypertensives, such as Olmesartan, used to treat hypertension, diabetic nephropathy and heart failure, can cause enteropathy. Although rare, this condition should be considered in patients with severe diarrhoea and weight loss. The exact pathophysiology is unknown, but a type I immune response and inhibition of TGF-β, a key molecule in intestinal homeostasis, are suspected. Olmesartan enteropathy occurs in both sexes, mainly in the elderly, and is characterised by chronic diarrhoea, weight loss and steatorrhoea. Laboratory abnormalities are variable, histological findings are non-specific and there is no response to a gluten-free diet. Clinical improvement after discontinuation of the drug confirms the diagnosis. Treatment consists of discontinuation of Olmesartan, which usually results in complete resolution of symptoms. The prognosis is excellent, and follow-up endoscopy is not required if symptoms improve after withdrawal of the drug and there is no diagnostic uncertainty with another entity.