Drug-induced urolithiasis.

Drugs can cause renal stone formation either by raising excretion rates of naturally occurring stone components or by directly precipitating within the urinary tract. In large series of analysed renal stones, the overall frequency of drug-induced urolithiasis is less than 0.5%. Five clinical presentations of drug-induced crystallization in the kidneys can be recognized: asymptomatic crystalluria, symptomatic crystalluria; stone passage; obstructive uropathy and tubulointerstitial nephritis. In the current literature review, the protease inhibitors used for treatment of patients infected with the human immunodeficiency virus stand out as a new class of drugs that frequently causes crystallization within the urinary tract. The most widely used compound, indinavir, may lead to crystalluria and renal stone formation in up to 50% of patients, and occasionally also causes acute renal failure caused by obstructive uropathy or tubulointerstitial nephritis. On the other hand, ritonavir appears more often to induce (reversible) acute renal failure than stone formation.