People living with HIV using Norvir (ritonavir)-boosted Reyataz (atazanavir) were roughly ten times more likely to experience kidney stones, compared with those using other Norvir-boosted protease inhibitor (PI)-based regimens, according to a review of patient data conducted by Japanese researchers published online ahead of print by Clinical Infectious Diseases. In their analysis of 1,240 people treated with a Norvir-boosted PI regimen between 2004 and 2010, 35 HIV-positive individuals experienced kidney stones—31 (88.5 percent) of whom were using Norvir-boosted Reyataz. The kidney stone incidence rate was 7 percent among those using Norvir-boosted Reyataz, compared with 0.5 percent among those using other Norvir-boosted PI regimens.  Additionally, six of 18 people who continued using Norvir-boosted Reyataz after being diagnosed with kidney stones experienced a recurrence after an average of five months. Norvir-boosted Reyataz “should be carefully prescribed to patients with predisposing factors for renal stone formation or those with chronic kidney disease,” the authors conclude. “For those who developed [Norvir-boosted Reyataz]-induced renal stones, discontinuation of [the regimen] is warranted because of the high risk of recurrence.”

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