Abstract: TH-PO0849
Chronic Diarrhea in an Older Patient with CKD: A Case for Caution
Session Information
- Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)
- 1900 Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)
Authors
- Shokravi, Samin, University of Florida, Gainesville, Florida, United States
- Kazory, Amir, University of Florida, Gainesville, Florida, United States
Introduction
Angiotensin II receptor blockers (ARBs) are widely used in the management of hypertension, heart failure, and chronic kidney disease (CKD). While these agents are generally considered safe and well-tolerated, they can be associated with a range of adverse effects. Importantly, some of these reactions appear to be drug-specific rather than a uniform class effect, underscoring the need for clinical awareness when evaluating unexplained symptoms in patients receiving ARB therapy.
Case Description
An 86-year-old woman with a history of CKD and hypertension presented with cramping abdominal pain, watery non-bloody diarrhea, weight loss, and fatigue of approximately one year’s duration. Extensive laboratory evaluation was inconclusive, which revealed a pancreatic elastase level of 800 µg/g (normal: >200 µg/g), a tissue transglutaminase (tTG) IgA level of 2 U/mL (normal:<4 U/mL), and a fecal calprotectin level of 83 µg/g (normal: <50 µg/g). Given the negative initial workup for chronic non-bloody diarrhea, colonoscopy with biopsy was performed, which showed no evidence of microscopic colitis. In the absence of serologic evidence of celiac disease, but with endoscopic findings suggestive of a sprue-like process in a patient receiving olmesartan, olmesartan-associated enteropathy (OAE) was diagnosed. The medicine was discontinued; the patient’s symptoms improved significantly, further supporting the diagnosis.
Discussion
Olmesartan can cause a sprue-like enteropathy that manifests as severe persistent diarrhea months to years after treatment begins. The mechanism of OAE involves immune-mediated intestinal damage that shares pathogenic features with autoimmune enteropathy and celiac disease. An increase in T-cell activity and interleukin-15, as well as enterocyte apoptosis secondary to unopposed angiotensin II type-2 (AT2) receptor activation following AT1 blockade, have been proposed as potential mechanisms. While laboratory evaluation predominantly reveals a severe non-specific malabsorption process, negative celiac serology is imperative in diagnosing OAE. Clinicians prescribing ARBs, particularly irbesartan, should be aware of this adverse effect, especially in elderly patients, as early identification can prevent unnecessary workup and improve outcomes. Discontinuation is usually sufficient, though steroids or immunosuppressants may be needed in severe, refractory cases.