Dyazide-induced reversible acute renal failure associated with intracellular crystal deposition

Acute interstitial nephritis due to Dyazide therapy, ie, a combination of hydrochlorothiazide (25 mg) and triamterene (50 mg), has been recently reported in the literature. This had been characterized by nonoliguric renal failure after a long latent period (weeks) following exposure to the drug. Pathologic data have indicated a drug-induced hypersensitivity reaction. We report here one case of oliguric acute renal failure after a massive Dyazide intoxication. Based on the results of the renal biopsy and clinical course, we propose that the oliguria was secondary to a direct toxic effect on the tubules, and intrarenal obstruction was secondary to triamterene crystals and crystal-laden cells. In addition, pathologic findings also suggested a moderate hypersensitivity reaction. After hemodialysis and short-term steroid therapy, the patient achieved complete recovery of renal function within 12 days. Recent knowledge of triamterene-induced nephrolithiasis helps to explain the pathogenesis of acute renal failure in this patient, and is briefly reviewed here.