Olmesartan has recently been reported as a cause of drug-induced enteropathy characterized by chronic diarrhoea and duodenal mucosal atrophy demonstrating sprue-like enteropathy. 82-year-old, male presented to our hospital because of chronic severe watery diarrhea without abdominal pain or fever. Blood examination showed mild anemia (Hb 11.2 mg/dl). Abdominal contrast-enhanced computed tomography showed mucosal edema in the large intestine. Esophagogastroduodenoscopy showed no villous atrophy in the duodenum with the possibility of pyloric gastrectomy, however, colonoscopy showed villous flattering in the terminal ileum and edematous changes in sigmoid colon. Histopathologic examination in biopsy samples from the terminal ileum and sigmoid colon showed interstitial lymphocytic infiltration. He was treated with olmesartan for hypertension at least two years before the onset of symptoms. In addition, watery diarrhea improved soon after discontinuation of olmesartan. Therefore, he was diagnosed as olmesartan-induced enteropathy. Its pathogenesis remains unclear; however, olmesartan-induced enteropathy must be included in the differential diagnosis for patients with chronic diarrhea after the intake of olmesartan.
