TreatmentUpdate81 - Vol. 9, No. 7 - pp. 7; September 1997
Sean Hosein

The anti-HIV drug indinavir (Crixivan) is the most widely used protease inhibitor in North America. According to the manufacturer, Merck Frosst, 4% of people who used the drug in clinical trials developed kidney stones (nephrolithiasis). Now a study of 240 people at the NIH (National Institutes of Health, Bethesda, Maryland) has confirmed the 4% figure but also found that 11% of all subjects developed symptoms of some degree of kidney damage. In most cases drinking extra water and, if necessary, temporarily stopping use of indinavir helped people recover.

Study Details

Researchers monitored 240 volunteers, all of whom had HIV-infection and were using indinavir 2.4 g/day. Their CD4+ counts ranged between 25 and 903 cells, with half having 472 cells. No subject had kidney stones before using indinavir and most subjects were male (details unavailable).

Results and recovery

Of the 240 subjects, 27 or 11% had symptoms of "urinary tract disease", that is;

* kidney stones - 9 subjects

* "flank or back pain without kidney stones" - 12 subjects

* painful or difficult urination - 6 subjects

In many cases, analysis of urine samples revealed crystals of indinavir in the urine of those subjects with symptoms. To help them recover, doctors gave them extra water and in some cases stopped the use of indinavir temporarily. When the subjects resumed taking indinavir, 9 had their symptoms reappear and 4 had to permanently stop using indinavir.

Crystals in urine

Only 142 of the 240 subjects provided urine samples for analysis. Lab workers found that 20% of the 142 subjects had crystals of indinavir in their urine without having any symptoms of kidney damage. The researchers found that the presence of indinavir crystals in the urine of these symptom-free subjects did not necessarily precede the development of symptoms of kidney damage. The doctors did, however, note that the presence of crystals in the urine of subjects with symptoms of urinary tract disease likely "suggests the need for increased [drinking of liquids] and possibly temporary [indinavir] withdrawal." Use of indinavir with the following drugs did not increase the risk of developing urinary tract disease:

* acyclovir

* AZT and 3TC

* d4T and 3TC

* Bactrim/Septra«

* vitamin C

REFERENCES:

1. Kopp JB, Miller KD, Mican JAM, et al. Crystalluria and urinary tract abnormalities associated with indinavir. Annals of Internal Medicine 1997;127:119-125.

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