Indinavir nephrotoxicity

In an animal model, indinavir nephrotoxicity was potentiated by co-trimoxazole, but nelfinavir alone or in combination with co-trimoxazole was not nephrotoxic (189). 

Although, the nephrotoxicity from the use of TMP-SMZ alone for long-term seems rare, TMP-SMZ can potentiate the renal toxic effects of other drugs concomitantly used in HIV-infected patients. In one retrospective study by Boubaker et al [111], 18.6% of HIV-infected patients treated with indinavir and TMP-SMZ had a sustained elevation of... 

Trainor ED, Steinberg JP, Austin GW, Solomon FIM. Indinavir crystalluria identification of patients at increased risk of developing nephrotoxicity. Arch Pathol Lab Med 1998 122 256-259. 

Acyclovir is eliminated in the urine by glomerular filtration and by active tubular secretion, which is inhibited by probenecid. Nephrotoxic effects, including hematuria and crystalluria, are enhanced in patients who are dehydrated or who have preexisting renal dysfunction. Adequate hydration is equally important in the case of indinavir, since it causes nephrolithiasis. However, more than 80% of a dose of indinavir is eliminated via hepatic metabolism. The answer is (A). 

Atazanavir/ritonavir, darunavir/ritonavir and lopinavir/ritonavir modestly increased the levels of tenofovir, and there is at least one case report of nephrotoxicity with the combination of tenofovir, didanosine, and lopinavir/ritonavir. Saquinavir/ritonavir, ti-pranavir/ritonavir, and probably also fosamprenavir/ritonavir, have little effect on tenofovir levels. Tenofovir modestly decreased atazanavir levels, and this was minimised when ritonavir was also given. Tenofovir had no important effect on ritonavir-boosted darunavir, lopinavir, and tipranavir levels, and modestly increased those of ritonavir-boosted saquinavir in one of two studies. Indinavir and nelfinavir do not interact pharmacokineti-cally with tenofovir. 

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