Do you take the protease inhibitor (PI) Reyataz (atazanavir)? If so, be sure to chug at least eight glasses of water a day. Downing H20 helps reduce the risk of developing kidney stones, a possible side effect of the PI, according to the FDA. If you experience kidney stone symptoms—excruciating pain in the lower back, side or groin, or blood in the urine—alert your doctor right away. Gulp.