Indinavir urolithiasis

Indinavir sulfate is a protease inhibitor that has been found to be extremely effective in increasing CD4+ cell counts and in decreasing HIV-RNA titers in patients with HIV and AIDS. However, patients receiving indinavir also have been noted to have a significant risk for developing urolithiasis. Published reports of indinavir urolithiasis estimate its incidence at between 4 and 13%. Indinavir has a high urinary excretion with poor solubility in a physiologic pH solution. Consequently, patients develop urinary stones that are principally composed of indinavir or of a mixture of indinavir and other substances, such as calcium oxalate. Similar to other forms of urolithiasis, acute flank pain and hematuria are the typical symptoms of indinavir urolithiasis. Indinavir urolithiasis is unique in that computed tomography, which was once thought to be efficacious in identifying all urinary calculi, is not useful in imaging stones that are composed of pure indinavir. Indinavir urolithiasis generally responds to a conservative regimen of hydration, pain control, and the temporary discontinuation of the medication. Only a minority of patients need surgical intervention. Approximately 10% of patients ultimately need to discontinue indinavir therapy altogether. Indinavir is an antiviral agent that has a significant role in the treatment of AIDS. Although urolithiasis is a significant side effect of indinavir use, limiting its clinical application is not the answer. Rather, physicians need to know more about indinavir urolithiasis to help their patients cope with its potential complications.