Emtricitabine/tenofovir disoproxil are medications used to treat HIV. They are antiretroviral drugs combined in one tablet. The usual adult dose is one tablet taken once a day along with another antiretroviral drug.

The tablet contains 200mg emtricitabine and 245mg tenofovir disoproxil. Emtricitabine/tenofovir disoproxil is sometimes marketed under the name Truvada, but generic versions are also available.

Emtricitabine/tenofovir disoproxil combines two drugs in one pill. Emtricitabine and tenofovir disoproxil are from a class of drugs known as NRTIs (nucleoside/nucleotide reverse transcriptase inhibitors).

Your doctor will prescribe emtricitabine/tenofovir disoproxil as part of your HIV treatment, along with an antiretroviral 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. Taking HIV treatment and having an undetectable viral load protects your immune system and stops HIV being passed on to someone else during sex.

You should take emtricitabine/tenofovir disoproxil once a day, ideally with food.

HIV treatment works best if you take it every day. If you forget to take a dose of emtricitabine/tenofovir disoproxil, and realise within 12 hours, then take it then and take your next dose at the usual time. If it’s less than 12 hours until your next dose is due, 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.

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 emtricitabine/tenofovir disoproxil.

We generally divide side-effects into two types:

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

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

The most common side-effects of emtricitabine/tenofovir are diarrhoea, being sick (vomiting), feeling sick (nausea), dizziness, headache, rash, feeling weak, pain, stomach pain, difficulty sleeping, abnormal dreams,  feeling bloated, flatulence, allergic reactions, such as wheezing, swelling or feeling light-headed.

Other side-effects might not have noticeable symptoms, but would be picked up by your regular blood tests – such as decreases in phosphate in the blood.

Emtricitabine/tenofovir disoproxil can affect the kidneys and bones, so it is not recommended for people with pre-existing severe kidney disease. Your kidney function will be monitored by your clinic.

It’s important that your doctor and pharmacist know about any other drugs you are taking. That includes medicine prescribed by another doctor, drugs you have bought from a high-street chemist, herbal and alternative treatments, and recreational drugs.

Some medicines should not be taken together because if they are this can cause serious side-effects, or it can 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.

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

You should not take emtricitabine/tenofovir disoproxil with any of the following drugs:

• tenofovir alafenamide
• lamivudine
• adefovir dipivoxil.

Taking emtricitabine/tenofovir disoproxil with some other drugs can increase the risk of kidney damage. It is very important to tell your doctor if you are taking any of the following drugs:

• aminoglycosides (for bacterial infection)
• amphotericin B (for fungal infection)
• foscarnet (for viral infection)
• ganciclovir (for viral infection)
• pentamidine (for infections)
• vancomycin (for bacterial infection)
• interleukin-2 (to treat cancer)
• cidofovir (for viral infection)
• non-steroidal anti-inflammatory drugs (NSAIDs, to relieve bone or muscle pains).

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 these drugs (in combination with one or two other drugs) 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. Emtricitabine/tenofovir disoproxil should not be used during breastfeeding as at least one of the drugs it contains passes into breast milk.

Emtricitabine/tenofovir disoproxil can be taken by children aged 12 years and over, weighing 35kg or more.

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 appoint – visit www.aidsmap.com/talking-points 

For detailed information on this drug, visit the emtricitabine/tenofovir disoproxil page in the A-Z of antiretroviral drugs.