Atazanvir

It is a preferred protease inhibitor. It inhibits HIV protease and is structurally unrelated to other HIV protease inhibitors. Atazanavir is well absorbed orally. It must be taken with food, because food increases absorption and bioavailability. The drug is highly protein bound (86 percent) and undergoes extensive CYP3A4-catalyzed biotransformation. It is excreted primarily in bile. Its half-life is about 7 hours, but it only needs to be administered once a day. Atazanavir is a competitive inhibitor of glucuronyl transferase, and benign hyperbilirubinemia and jaundice are known side effects. In the heart, atazanavir prolongs the PR interval and slows the heart rate. Atazanavir exhibits a decreased risk of hyperlipidemia, but it is not known if atazanavir is less likely to cause insulin resistance and lipodystrophy, as seen with other protease inhibitors. Like the other protease inhibitors, atazanavir is a potent inhibitor of CYP3A4 and has the potential for many drug interactions. Unboosted atazanavir is contraindicated with the use of proton-pump inhibitors, and administration must be spaced 10 hours apart from H2-blockers and 1 hour after taking antacids.