Drug-induced crystal nephropathy: an update

Background: Several medications that are insoluble in human urine are known to precipitate within the renal tubules. Intratubular precipitation of either exogenously administered medications or endogenous crystals (induced by certain drugs) can promote chronic and acute kidney injury, termed crystal nephropathy. Clinical settings that enhance the risk of drug or endogenous crystal precipitation within the kidney tubules include true or effective intravascular volume depletion, underlying kidney disease, and certain metabolic disturbances that promote changes in urinary pH favoring crystal precipitation. Objective: Identify and review previously described and recently recognized medications that cause crystal nephropathy. Method: A literature review was performed, using PubMed, Ovid, and Google Scholar, focusing on drugs (sulfadiazine, acyclovir, indinavir, triamterene, methotrexate (MTX), orlistat, oral sodium phosphate preparation, ciprofloxacin) that cause crystal nephropathy. Results/conclusion: Sulfadiazine, acylcovir, indinavir, triamterene, and MTX are known to cause crystal nephropathy. Recently, several medications, including orlistat, ciprofloxacin, and oral sodium phosphate solution, along with underlying risk factors have been described as causing crystal nephropathy.