Indinavir is an antiretroviral (protease inhibitor) medication used in the treatment of HIV infections.  It easily precipitates to form crystals.  People who take this drug are instructed to drink large amounts of water in order to create a large urine volume which helps to dissolve the medication in the urine.

Diagnosis can be difficult.  Many patients who come in with symptoms of kidney stones are likely to have a CT scan or an xray of the kidneys which may not show indinavir stones.  Indinavir stones often are difficult to detect on these tests.  However, they should be visible on an ultrasound.  It is critical to differentiate these stones from uric acid stones which sometimes can also be difficult to detect.  Uric acid stones are treated with citrate (alkali) therapy to raise urine pH (decrease acidity) while this same treatment could actually promote formation of Crixivan stones.

Physicians treating people with HIV and  uric acid stones, should consider prescribing a medication other than indinavir if possible.