Mesalazine-induced renal calculi

PATIENT Female, 32 FINAL DIAGNOSIS: Renal colic Symptoms: Acute colic pain • macrohematuria MEDICATION Mesalazine Clinical Procedure: CT scan of urinary tract • cystoscopy • gynecological consultation • stone analysis Specialty: Gastroenterology and Hepatology • Clinical Pharmacology. OBJECTIVE Unexpected drug reaction. BACKGROUND Mesalazine, a 5-aminosalicylic acid compound, is one of the cornerstones in modern treatment regimens of ulcerative colitis. It is generally well tolerated, although adverse reactions such as nephrotoxicity, perimyocarditis, and pancreatitis have been reported. CASE REPORT We report the case of a 32-year-old woman with colitis who developed recurrent episodes of renal colic after introduction of mesalazine to her treatment. Biochemical analysis of the stones showed that they were composed of crystalized drug material. CONCLUSIONS To our knowledge this is the first report of mesalazine precipitation in the urinary tract. We believe that it is vital for physicians to recognize this potentially severe adverse effect in the use of this treatment.