Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Body fat changes: People using atazanavir may notice the accumulation and redistribution of fat in their body. For example, less body fat on their arms, legs, and face, and more around the centre of their body (e.g., enlarged breasts, abdominal or central obesity, and a "buffalo hump" - a pad of fat on the back). The cause or long-term health effects of these changes are not known at this time.
Diabetes: Some people taking protease inhibitor medications such as atazanavir have developed diabetes during treatment, and some people who already had diabetes noticed that their diabetes became worse during treatment. If you have diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Heart effects: Atazanavir can affect the heart rhythm (heartbeat) in some people. If you have problems with the electrical conduction system of your heart (e.g., first-, second-, and third-degree AV block) or are taking medications that affect the electrical conduction system of the heart (e.g., diltiazem, verapamil), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Hemophilia: People with hemophilia A or B may be at an increased risk of bleeding while taking atazanavir. If you have a bleeding condition, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Gallstones: Atazanavir can cause gallstones, concentrations of the bile that is produced by the liver. If you experience symptoms of gallstones, such as persistent severe pain on the right side of your abdomen, nausea and vomiting, or pain between the shoulder blades or under the right shoulder, contact your doctor as soon as possible.
Immune reconstitution syndrome: When you start taking HIV medications such as atazanavir, your immune system may get stronger and start to fight other infections that have been hidden in your body (e.g., pneumonia, herpes, or tuberculosis). Contact your doctor if you develop any new symptoms after starting HIV medications such as atazanavir.
Kidney stones: Some people taking atazanavir have developed kidney stones. If you develop signs or symptoms of kidney stones (e.g., pain in your side, blood in your urine, or pain when you urinate), contact your doctor immediately.
Lactic acidosis: People taking atazanavir in combination with some other HIV medications (e.g., abacavir, didanosine, lamivudine, stavudine, zalcitabine, and zidovudine) may be at risk of a serious condition called lactic acidosis. Lactic acidosis is a buildup of lactic acid in the blood. If you notice any of the symptoms of lactic acidosis, such as difficulty breathing, abdominal pain, muscle weakness, nausea, and vomiting, stop taking this medication and contact your doctor immediately.
Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. This medication can also cause liver failure and reduced liver function. People with hepatitis B or C, or liver disease, may experience worsening of their liver disease symptoms while taking this medication. Your doctor will monitor your liver function while you are taking atazanavir. Report any signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools) to your doctor immediately. People with severe liver disease should not take this medication.
Other medications: Atazanavir may interact with a number of medications, which may mean a change in how you take this medication (see "What medications can interact with this medication?"). Tell your doctor of all medications that you are taking. Certain medications should not be taken with atazanavir at all (see "Who should NOT take this medication?").
Atazanavir should never be used alone; it should always be used in combination with other HIV medications.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: It is not known if atazanavir passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Breast-feeding is not recommended for HIV-positive women since the virus can be transmitted through breast milk.
Children and adolescents: The safety and effectiveness of using this medication have not been established for children between 3 months and 6 years of age. Do not give this medication to children younger than 3 months as it can cause a form of brain damage known as kernicterus.