A French study, published in the September 12 issue of Clinical Infectious Diseases, mirrors another report from the United States suggesting that kidney stones may be a side effect of the protease inhibitor Reyataz.  Approximately one percent of people in the study developed kidney stones, and the risk was higher in those who’d previously had them.

A team headed by Carine Couzigou, MD, of Hôpital Paul Brousse in Villejuif, analyzed the medical records of 1,134 people taking Reyataz in France. They found 11 patients who had developed kidney stones. Though none had a history of serious kidney problems, four had previously developed kidney stones before taking Reyataz. All 11 were taking Reyataz boosted with low-dose Norvir. The majority of the kidney stones analyzed were made up primarily of crystallized Reyataz. After passing the kidney stones, six stayed on Reyataz and five switched it for another drug. Of those who continued Reyataz, all were instructed to increase their intake of fluids and to drink more acidic drinks, such as citrus juices. One person who continued on Reyataz had a recurrence of kidney stones 10 months later.

In light of the many thousands of people who’ve taken Reyataz, the number of kidney stone reports has been very low. Also, researchers in this study could not determine how and why the kidney stones developed. They did, however, hypothesize that having a history of kidney stones may increase the risk of developing them while taking Reyataz. There was also some evidence suggesting that those who developed kidney stones were not drinking enough fluids, especially acidic drinks.