Atazanavir belongs to the class of medications known as azapeptide HIV-1 protease inhibitors. It is used in combination with other medications to treat human immunodeficiency virus 1 (HIV-1) infection. HIV is the virus responsible for acquired immunodeficiency syndrome (AIDS). HIV infection destroys CD4 (T) cells, which are important to the immune system. The immune system helps fight infections.

Atazanavir reduces the amount of HIV in the blood by interfering with the enzyme protease that the HIV virus needs in order to multiply. Atazanavir may also help the immune system by increasing the number of CD4 (T) cells in the body.

This medication does not cure HIV infection or AIDS and does not reduce the risk of passing HIV on to others through sexual contact or blood contamination.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult dose of atazanavir is 300 mg taken once daily with food, along with 100 mg of ritonavir. If ritonavir is not tolerated, the dose of atazanavir should be increased to 400 mg once daily with food. This medication should be taken at the same time each day and swallowed whole (do not open the capsules) with a glass of water.

Atazanavir should never be used alone and should always be used in combination with other HIV medications. Your doctor may choose other doses of atazanavir, depending on which other HIV medications you are taking.

The recommended dose for children ages 6 to 18 is based on body weight and calculated by the doctor. This medication is not recommended for children weighing less than 20 kg or those who are less than 6 years old.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible with food and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect from moisture, and keep it out of the reach of children.

150 mg
Each hard-shell gelatin capsule with a greenish-blue opaque cap and blue opaque body, axially printed with "MYLAN" over "AR150" in black ink on both the cap and body, and filled with white-to-pale-yellow powder, contains atazanavir sulfate equivalent to 150 mg of atazanavir. Nonmedicinal ingredients: crospovidone, lactose monohydrate, magnesium stearate; capsule shell: D&C Red 28, FD&C Blue No. 1, FD&C Red No. 3, gelatin, iron oxide yellow, and titanium dioxide; black imprinting ink: black iron oxide, potassium hydroxide, propylene glycol, shellac, and strong ammonia solution. 

200 mg 
Each hard-shell gelatin capsule with a blue opaque cap and blue opaque body, axially printed with "MYLAN" over "ARC200" in black ink on both the cap and body, and filled with white-to-pale-yellow powder, contains atazanavir sulfate equivalent to 200 mg of atazanavir. Nonmedicinal ingredients: crospovidone, lactose monohydrate, magnesium stearate; capsule shell: FD&C Blue No. 1, FD&C Red No. 3, gelatin, and titanium dioxide; black imprinting ink: black iron oxide, potassium hydroxide, propylene glycol, shellac, and strong ammonia solution. 

300 mg
Each hard-shell gelatin capsule with a red opaque cap and greenish-blue opaque body, axially printed with "MYLAN" over "AR300" in black ink on both the cap and body, and filled with white-to-pale-yellow powder, contains atazanavir sulfate equivalent to 300 mg of atazanavir. Nonmedicinal ingredients: crospovidone, lactose monohydrate, magnesium stearate; capsule shell: FD&C Blue No. 1, FD&C Red No. 3, iron oxide red, iron oxide yellow, gelatin, and titanium dioxide; black imprinting ink: black iron oxide, potassium hydroxide, propylene glycol, shellac, and strong ammonia solution.

Do not take atazanavir if you:

• are allergic to atazanavir or any ingredients of the medication
• are taking any of the following medications:
• alfuzosin
• apalutamide
• apixaban (if also taking ritonavir)
• ergot-type medications (i.e., dihydroergotamine, ergonovine, ergotamine, or methylergonovine)
• hepatitis C direct acting antivirals (e.g., elbasvir, grazoprevir, glecaprevir, pibrentasvir)
• indinavir
• irinotecan
• lovastatin
• lomitapide
• lurasidone (if also taking ritonavir)
• nevirapine
• pimozide
• quinidine
• rifampin
• rivaroxaban (if also taking ritonavir)
• sildenafil (when used for pulmonary arterial hypertension)
• simvastatin
• St. John's wort
• ticagrelor
• triazolam

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• diarrhea
• dizziness
• headache
• heartburn
• nausea or vomiting (infrequent)
• rash, itchiness
• trouble sleeping

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• fever
• muscle pain
• nausea or vomiting (frequent)
• rapid heartbeat
• signs of gallstones (e.g., nausea, vomiting, severe abdominal pain)
• 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)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• symptoms of an autoimmune disorder (e.g., fever, unusual joint or muscle pain, rash, fatigue)
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of irregular heartbeat (e.g., chest pain, dizziness, rapid, pounding heartbeat, shortness of breath)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of an allergic reaction (shortness of breath or difficulty breathing; hives; swelling of the eyes, mouth, lips, or throat)
• signs of kidney stones (pain in your side, blood in urine, pain when urinating)
• symptoms of a condition called lactic acidosis (unusual weakness or tiredness, unusual muscle pain, stomach pain with nausea and vomiting, feeling cold especially in arms and legs, dizziness or lightheadedness, and fast or irregular heartbeat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

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.

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.

Fat redistribution: Over time, this medication may change how fat is distributed in your body and may change your body shape. You may notice increased fat in the upper back and neck, breast, around the back, chest, and stomach area; or loss of fat from the legs, arms, and face. The long-term effects of this are not known.

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.

Heart effects: Atazanavir can affect heart rhythm (heartbeat) for 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.

Immune reconstitution inflammatory 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 function: Chronic kidney disease has been reported with the use of atazanavir. If you have a history of kidney disease, 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.

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, 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.

Lactose: This medication contains lactose. If you have hereditary problems of galactose intolerance, lactase deficiency, or glucose-galactose malabsorption, talk to your doctor about whether this medication is appropriate for you.

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 about all the 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: This medication passes into breast milk. If you are breast-feeding and taking atazanavir, it may affect your baby. Breast-feeding is not recommended for HIV-positive people 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, or children weighing less than 20 kg. Do not give this medication to children younger than 3 months as it can cause a form of brain damage known as kernicterus.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.