What is efavirenz/emtricitabine/tenofovir disoproxil?
Efavirenz/emtricitabine/tenofovir disoproxil are medications used to treat HIV. They are antiretroviral drugs combined in one pill, taken once a day.
The pill combines 600mg efavirenz, 200mg emtricitabine and 245mg tenofovir disoproxil. It is often marketed under the name Atripla, but generic versions are also available.
How does it work?
Two of the drugs (emtricitabine and tenofovir disoproxil) are from a class of drugs known as NRTIs (nucleoside/nucleotide reverse transcriptase inhibitors). The third drug, efavirenz, is a non-nucleoside reverse transcriptase inhibitor (NNRTI). Each drug class works against HIV in a different way.
The aim of HIV treatment is to reduce the level of HIV (the ‘viral load’) in your body until 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 it?
You should take efavirenz/emtricitabine/tenofovir disoproxil once a day. The tablet should be swallowed whole; do not chew, crush or split it. Taking it on an empty stomach (i.e. one hour before or two hours after food) can reduce the risk of some side-effects, including drowsiness and abnormal dreams.
Many people who have taken efavirenz/emtricitabine/tenofovir disoproxil have found that it is best to take it before going to bed. This is because the side-effects include feeling drowsy or dizzy.
HIV treatment works best if you take it every day, ideally at the same time each day. It may help to set an alarm, e.g. on your mobile phone, to remind you. If you forget to take a dose of efavirenz/emtricitabine/tenofovir disoproxil and realise within 12 hours of the time you usually take it, take it as soon as possible then take your next dose at your usual time. If you realise more than 12 hours late don’t take a double dose, just skip the dose you’ve forgotten and then carry on with your normal routine.
If you are sick (vomit) within 1 hour of taking your efavirenz/emtricitabine/tenofovir disoproxil tablet, you should take another tablet; if you vomit more than 1 hour after your dose there is no need to repeat the dose.
What are the possible side-effects?
All medicines have possible side-effects. It’s a good idea to talk to your doctor, nurse or pharmacist about what to expect before you start taking any medication, and how to manage any side-effects which occur.
A full list of side-effects, including less common side-effects, can be found in the patient information leaflet that comes with efavirenz/emtricitabine/tenofovir disoproxil.
Side-effects can be described as:
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 efavirenz/emtricitabine/tenofovir disoproxil include (most common in bold):
- dizziness, headache, difficulty sleeping, abnormal dreams, difficulty concentrating, drowsiness, weakness. These may occur within the first day or two of taking efavirenz/emtricitabine/tenofovir disoproxil and should wear off within the first two to four weeks.
- nausea (feeling sick), vomiting (being sick), diarrhoea, stomach pains, feeling bloated, flatulence.
- skin rash, allergic reaction, dark skin patches (often starting on the hands or soles of feet). You should discuss any skin rash with your doctor as soon as possible.
- changes in the results of some blood tests (e.g. liver and kidney tests, cholesterol).
Efavirenz/emtricitabine/tenofovir disoproxil can also have side-effects which affect your mental health. It is common to feel worried, anxious or depressed. Some people have experienced more serious side-effects such as suicidal thoughts, paranoia and mood changes, which are uncommon. It is more likely that you will experience these serious side-effects if you have a history of mental illness. Talk to your doctor if you have concerns about these side-effects, particularly if you think you are experiencing any of them.
Does it 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.
If you are taking efavirenz/emtricitabine/tenofovir disoproxil it’s important to check with your HIV doctor or pharmacist before taking any medicines from the following groups:
- antiepileptic medication
- anticoagulants (medication to thin the blood)
- medication for high blood pressure
- medication to lower cholesterol (e.g. statins)
- herbal medicines – in particular St Johns Wort and Ginkgo biloba should not be taken
- contraceptives (birth control) – efavirenz/emtricitabine/tenofovir disoproxil can make some contraceptives less effective. Your healthcare team will help choose the right method of contraception for you.
The patient information leaflet which comes with your HIV treatment has a full list of medicines which should be avoided.
Can I take it 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.
Efavirenz/emtricitabine/tenofovir disoproxil's manufacturers do not recommend using the drug during pregnancy.
However, many women have taken the treatment while pregnant without any problems. 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 efavirenz/emtricitabine/tenofovir disoproxil 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. Efavirenz/emtricitabine/tenofovir disoproxil should not be used during breastfeeding as at least one of the drugs it contains passes into breast milk.
Can children take it?
Efavirenz/emtricitabine/tenofovir disoproxil is not licensed for use in children.
Talking to your doctor
If you have any concerns about your treatment or other aspects of your health, it’s important to talk about these. For example, if you have any symptom or side-effect which may be from your treatment, or if you are finding it difficult to take your medication every day, one of your healthcare team will be able to help.
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.
For detailed information on this drug, visit the efavirenz/emtricitabine/tenofovir disoproxil page in the A-Z of antiretroviral medications.