Pharmacy Author: Omudhome Ogbru, Pharm.D.
Medical Editor: Jay Marks, M.D.

GENERIC NAME: atazanavir

BRAND NAME: Reyataz

DRUG CLASS AND MECHANISM: Atazanavir is an oral medication that is used for treating infections caused by the human immunodeficiency virus (HIV). It is in a class of drugs called protease inhibitors that also includes ritonavir (Norvir), nelfinavir (Viracept), indinavir (Crixivan) and saquinavir (Invirase, Fortovase). During infection with HIV, the HIV virus multiplies within the body's cells. Viruses are released from the cells and spread throughout the body where they infect other cells. In this manner, HIV infection is perpetuated among new cells that the body produces continually. During the production of the viruses, new proteins must be made. Some of the proteins are structural proteins, that, is, proteins that form the body of the new viruses. Other proteins are enzymes that manufacture DNA and other components for the new viruses. Protease is the enzyme that forms the new structural proteins and enzymes. Atazanavir blocks the activity of protease and results in the formation of new viruses with defective proteins that are unable to infect the body's cells. As a result, the number of viruses in the body (the viral load) decreases. Nevertheless, atazanavir does not prevent the transmission of HIV among individuals, and it does not cure HIV infections or AIDS. Atazanavir was approved by the FDA in June, 2003.

PRESCRIPTION: Yes

GENERIC AVAILABLE: No

PREPARATIONS: Capsules: 100, 150, 200 mg

STORAGE: Store at room temperature between 15-30°C (59-86°F).

PRESCRIBED FOR: Atazanavir is used in combination with other drugs for the treatment of infections with HIV.

DOSING: The starting dose of atazanavir for adults is 400 mg once daily with food. Ritonavir (Norvir) increases the concentration of atazanavir in the blood. Therefore, when atazanavir is administered with ritonavir, the dose of atazanavir should be reduced to 300 mg daily. Efavirenz (Sustiva) decreases the concentration of atazanavir in the blood. Therefore, when patients are receiving both atazanavir and efavirenz, 100 mg of ritonavir also should be added in order to keep the levels of atazanavir in the blood at the desired levels.

DRUG INTERACTIONS: Atazanavir inhibits the enzymes that eliminate many drugs from the body. Administration of these drugs along with atazanavir may result in increased concentrations of these drugs and cause more side effects. Atazanavir also is eliminated by enzymes in the liver, and drugs that increase the activity of these enzymes may decrease the concentration of atazanavir in the blood and reduce the effect of atazanavir. Conversely, drugs that prevent the elimination of atazanavir may increase the concentration of atazanavir in the blood and cause increased atazanavir-related side effects. Some of the important potential or known interactions are mentioned below. Viewers should consult their healthcare provider before combining any drugs with atazanavir.

Rifampin (Rifadin), St. John's Wort and efavirenz (Sustiva) decrease the blood levels of atazanavir and this can reduce the effect of atazanavir.

Atazanavir decreases the elimination and, therefore, could increase the side effects of triazolam (Halcion), midazolam (Versed), bepridil (Vascor), verapamil (Isoptin) , diltiazem (Cardizem), sildenafil (Viagra), lovastatin (Mevacor) , simvastatin (Zocor), atorvastatin (Lipitor), pimozide (Orap), (irinotecan (Camptosar), cyclosporine (Sandimmune), rifabutin (Mycobutin), amiodarone (Cordarone), clarithromycin (Biaxin) and ergot drugs (Migranal, Cafergot). Atazanavir is best absorbed under acidic conditions. Therefore, medications that decrease stomach acidity could reduce the absorption of atazanavir. Drugs that decrease stomach acidity include antacids, proton pump inhibitors such as omeprazole (Prilosec), lansoprazole (Prevacid), pantoprazole (Protonix), rabeprazole (Aciphex) esomeprazole (Nexium): H2-receptor antagonists such as cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid) and nizatidine (Axid): and buffered drugs such as didanosine (Videx)). Individuals who are taking antacids or didanosine should take their atazanavir two hours before or one hour after the didanosine or antacid.

PREGNANCY: Atazanavir has not been adequately studied in pregnant women.

NURSING MOTHERS: Atazanavir has not been adequately studied in nursing mothers. Scientific experts advise HIV-infected mothers not to breast-feed because of the risk of transmitting HIV to the infant.

SIDE EFFECTS: The most common side effects of atazanavir are rash, nausea, diarrhea, vomiting, headache and abdominal pain. Atazanavir may cause jaundice by increasing bilirubin in the blood. Some patients also may see an increase in blood glucose levels or an increase or redistribution of body fat. Changes in body fat may include increased fat in the upper back and neck (buffalo hump), trunk and breasts. In a small number of patients atazanavir may decrease heart rate. In a small number of patients a serious condition called lactic acidosis--a build up of acid in the blood--may occur. Symptoms of lactic acidosis include persistent nausea, vomiting, weakness and trouble breathing. Individuals with bleeding disorders may bleed more when taking atazanavir.

Printer-Friendly Format

|

Email to a Friend

From the Doctors at MedicineNet.com

Human Immunodeficiency Virus - Read about HIV (human immunodeficiency virus) causes, symptoms, treatment, prevention, transmission, facts, testing, research (into vaccines), statistics and AIDS (acquired immunodeficiency syndrome). Source:MedicineNet Read 19 more atazanavir related articles ... Health Tip: Treating an Ulcer Health Tip: Discussing Death With Children Breast Cancer Tends to Grow Faster in Younger Women Mental Illness Costs U.S. Billions in Lost Earnings Health Highlights: May 8, 2008 Computer Program Helps Drug Abusers Stay Clean TV Coverage of Tragedies Often Lacks Prevention Messages Secret to Treating Tinnitus in Vets May Be Unlocked in Zebrafish Gene Variant Boosts Risk of Severe Diabetic Eye, Kidney Diseases Outside Workers Least Likely to Get Skin Exams

Back to Medications Index

Last Editorial Review: 7/17/2003 10:04:37 AM