Atazanavir and cobicistat and Nephrolithiasis

Cases of nephrolithiasis, some of which resulted in acute interstitial nephritis, renal failure, and/or hospitalization, have been reported during postmarketing surveillance in HIV-infected patients receiving atazanavir therapy. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made. The median time between atazanavir initiation and the onset of nephrolithiasis was 1.7 years, with a range of 5 weeks to 6 years. Therapy with atazanavir should be administered cautiously in patients with a current or past history of nephrolithiasis, as well as possible risk factors such as renal and/or hepatic insufficiency. Adequate hydration and/or urine acidification may help reduce the risk. However, urine acidification may be poorly tolerated and possibly harmful, particularly in patients receiving concomitant treatment with sulfonamide antibiotics. Patients who are dehydrated may also be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluids if necessary. Patients should be instructed to seek medical attention if they experience potential signs and symptoms of nephrolithiasis/urolithiasis such as flank pain, hematuria, dysuria, anuria, and urinary urgency. Temporary interruption or discontinuation of therapy may be required.