OMEPRAZOLE-INDUCED INTERSTITIAL NEPHRITIS

Acute renal impairment secondary to interstitial nephritis is a rare c omplication of omeprazole. We describe a 50-year-old woman who took 20 mg omeprazole twice daily for endoscopically proved ulcerative esopha gitis. At the same time, Duke's C colonic cancer was diagnosed and com pletely resected. Five fluorouracil/folinic acid adjuvant chemotherapy was tolerated without diarrhea or mouth ulceration. Renal function wa s normal before her first monthly cycle bur markedly deteriorated imme diately before the second cycle was due. The patient was symptomatic w ith lethargy, nausea, and mild vomiting, but she was clinically normot ensive and only mildly dehydrated. Her serum creatinine concentration increased despite prolonged intravenous hydration, peaking at 4.4 mg/d l 1 week later. Results of a renal ultrasound were normal, and urinary microscopic findings were unremarkable. Renal biopsy showed interstit ial nephritis, and renal function improved on cessation of omeprazole, eventually returning to normal. We describe the 12 cases of omeprazol e-induced interstitial nephritis reported previously.