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Greta Hughson

What is atazanavir?

Atazanavir is a medication used to treat HIV. It is marketed under the brand name Reyataz, but generic versions are also available. It is taken in combination with other antiretroviral drugs.

The usual adult dose of atazanavir is 300mg taken once a day. This can be taken as one 300mg capsule taken with 100mg ritonavir (a boosting drug). Alternatively, the combination pill Evotaz contains 300mg of atazanavir and 150mg of cobicistat (a boosting drug) and this can be taken once a day.

How does atazanavir work?

Atazanavir is from a class of drugs known as protease inhibitors. Your doctor will prescribe atazanavir as part of your HIV treatment, along with antiretrovirals from another class of drugs. It is important to take all the drugs as prescribed, every day. Each drug class works against HIV in a different way.

The aim of HIV treatment is to reduce the level of HIV in your body (viral load). Ideally, your viral load should become so low that it is undetectable – usually less than 50 copies of virus per ml of blood. Taking HIV treatment and having an undetectable viral load protects your immune system and stops HIV being passed on to someone else during sex.

How do I take atazanavir?

You should take atazanavir with a meal or a large snack to help your body absorb the drug.

HIV treatment works best if you take it every day. When would be a good time for you to plan to take your treatment? Think about your daily routine and when you will find it easiest to take your treatment.

If you forget to take a dose of atazanavir, take it as soon as you remember with food. If it is nearly time for your next dose then don’t take a double dose, just skip the dose you’ve forgotten and carry on.

If you regularly forget to take your treatment, or you aren’t taking it for another reason, it’s important to talk to your doctor about this.

What are the possible side-effects of atazanavir?

All drugs have possible side-effects. It’s a good idea to talk to your doctor about possible side-effects before you start taking a drug. If you experience something that might be a side-effect, talk to your doctor about what can be done. A full list of side-effects, including less common side-effects, should be included in the leaflet that comes in the packaging with atazanavir.

We generally divide side-effects into two types:

Common – a side-effect that occurs in at least one in a hundred people (more than 1%) who take this drug.

Rare – a side-effect that occurs in fewer than one in a hundred people (less than 1%) who take this drug.

Common side-effects of atazanavir include:

  • Headache, nausea, vomiting, diarrhoea, abdominal pain, indigestion, tiredness, rash, raised bilirubin levels, sometimes leading to jaundice.

When taken as Evotaz, some other side-effects are reported as being common, including:

  • Increased appetite, difficulty in sleeping, abnormal dreams, dizziness, altered taste, bloating, flatulence, dry mouth.

Developing some yellowing of the skin and/or eyes (jaundice) is fairly common when taking atazanavir, especially when you first start the drug. Although this can look alarming, it is harmless and does not mean that your liver is damaged, or not working in any way.

Rarely, atazanavir can cause a hypersensitivity (allergic) reaction. If you develop a rash with other symptoms, such as a fever, seek medical advice.

Does atazanavir interact with other drugs?

You should always tell your doctor and pharmacist about any other drugs or medication you are taking. That includes anything prescribed by another doctor, medicines you have bought from a high-street chemist, herbal and alternative treatments, and recreational or party drugs (‘chems’).

Some medicines or drugs are not safe if taken together – the interaction could cause increased, dangerous levels, or it could stop one or both of the drugs from working. Other drug interactions are less dangerous but still need to be taken seriously. If levels of one drug are affected, you may need to change the dose you take. This must only be done on the advice of your HIV doctor.

A list of drugs, known to have interactions with atazanavir,should be included in the leaflet that comes in the packaging with atazanavir. Tell your doctor if you are taking any of these drugs, and other drugs that are not on the list.

You should not take atazanavir with any of the following medicines:

  • alfuzosin
  • astemizole
  • bepridil
  • cisapride
  • dihydroergotamine
  • ergonovine
  • ergotamine
  • grazoprevir
  • lovastatin
  • methylergonovine
  • midazolam (oral)
  • pimozide
  • quetiapine
  • quinidine
  • rifampicin
  • sildenafil (when used to treat pulmonary arterial hypertension)
  • simvastatin
  • St John’s wort
  • terfenadine
  • triazolam.

If you are taking atazanavir, it is particularly important to check with your HIV doctor or pharmacist before taking other medicines, as these may interact with atazanavir or with the boosting drugs ritonavir or cobicistat.

Drugs that affect the acidity of your stomach and gastrointestinal tract can stop atazanavir being absorbed, meaning it may not be effective at suppressing HIV. This includes remedies for indigestion and heartburn, proton pump inhibitors and H2-receptor antagonists. Talk to your doctor if you take these types of drugs, even if only occasionally.

Can I take atazanavir in pregnancy?

If you are considering having a baby, or think you might be pregnant, talk to your doctor as soon as possible about which combination of anti-HIV medications would be right for you. It is important to take antiretroviral treatment during pregnancy to prevent passing HIV from mother to baby.

The British HIV Association (BHIVA) recommends that women who are already taking anti-HIV medications and become pregnant can usually continue to take the same medication throughout their pregnancy. In addition, BHIVA lists atazanavir (in combination with other medications) as an option that may be recommended for women who start HIV treatment in pregnancy, depending on their individual circumstances.

Women living with HIV are advised not to breastfeed, as HIV can be passed on in breast milk. However, some women do choose to breastfeed. Atazanavir should not be used during breastfeeding as a small amount of the drug may pass into breast milk.

Can children take atazanavir?

Atazanavir is approved for use in children aged 6 years and over. Reyataz powder is also available for infants over 3 months.

Talking to your doctor

If you have any concerns about your treatment or other aspects of your health, it’s important to talk to your doctor about them.

For example, if you have a symptom or side-effect or if you are having problems taking your treatment every day, it’s important that your doctor knows about this. If you are taking any other medication or recreational drugs, or if you have another medical condition, this is also important for your doctor to know about.

Building a relationship with a doctor may take time. You may feel very comfortable talking to your doctor, but some people find it more difficult, particularly when talking about sex, mental health, or symptoms they find embarrassing. It’s also easy to forget things you wanted to talk about.

Preparing for an appointment can be very helpful. Take some time to think about what you are going to say. You might find it helpful to talk to someone else first, or to make some notes and bring them to your appointment. Our online tool Talking points may help you to prepare for your next appointment – visit 

For detailed information on this drug, visit the atazanavir pages in the A-Z of antiretroviral drugs.


Published March 2019

Last reviewed October 2017

Next review October 2020

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.