Emtricitabine/Tenofovir (PrEP)

Emtricitabine/tenofovir is a medication that is used to control HIV. It’s made up of two active ingredients (emtricitabine and tenofovir). It’s taken as a pre-exposure prophylaxis (shortened to PrEP). This type of drug is used to prevent someone contracting HIV.

Emtricitabine/tenofovir works by stopping the virus from multiplying in the body when you're first exposed to it, and stops it causing an infection. It does not cure an HIV infection.

Emtricitabine/tenofovir can also be used as part of the therapy to treat you if you’re HIV positive. ZAVA does not offer this medication as an HIV treatment.

Truvada is a brand name for emtricitabine/tenofovir. It is not commonly available in the UK, where the unbranded ‘generic PrEP’ is more often prescribed instead.

Both Truvada and ‘generic PrEP’ contain the same combination of the active ingredients emtricitabine and tenofovir. Both medications are equally effective in preventing HIV.

Emtricitabine/tenofovir has been found to be highly effective for preventing HIV infection when taken as instructed.

ZAVA can prescribe emtricitabine/tenofovir if you:

• are a man or woman over 18 years old
• have tested negative for HIV
• are at a higher risk of getting HIV

You might have a higher risk if you do not use condoms when having sex with someone whose HIV status is not clear to you, and you’re:

• a man who has sex with men
• a transgender person who has sex with men
• a woman who has sex with bisexual people
• having sex with someone from a country with a high rate of HIV

You also might have a higher risk of getting HIV if you:

• are having sex with someone who is HIV positive and has a detectable viral load (the amount of the virus in their blood is able to be found)
• are taking drugs using needles and sharing those needles with others
• are a sex worker
• get STIs (sexually transmitted infections) on a regular basis

There could be other reasons not listed here that put you at a higher risk of getting HIV.

For ZAVA to prescribe PrEP, we'll need to know that you've tested negative for:

• HIV
• kidney function (creatinine and estimated Glomerular Filtration Rate; eGFR)
• hepatitis B and C

Our Full pre-PrEP test kit covers all of these.

If you already know your hepatitis status, or have been vaccinated, we offer a Basic pre-PrEP test kit which includes tests for:

• HIV
• kidney function (creatinine and estimated Glomerular Filtration Rate; eGFR)

It's also recommended that you do an STI screen at this stage. ZAVA offers the following STI screening kits:

• men who have sex with men STI screen
• men who have sex with women STI screen
• women's STI screen

Why is it important to be HIV negative before and during PrEP therapy?

You should only take emtricitabine/tenofovir if you’ve tested negative for HIV. While on emtricitabine/tenofovir therapy, it’s also important to get tested regularly to make sure you’re still HIV negative.

Both emtricitabine and tenofovir are part of a combination of drugs used to treat HIV, but they are not used alone to treat HIV infection.

If you become HIV positive and unknowingly continue taking emtricitabine/tenofovir on its own, there is a risk you may develop resistance to HIV treatment later, which may affect how long you will stay healthy, living with HIV. Also, there is a chance you may pass on drug-resistant strains of HIV to others too.

How long after having unprotected sex should I test for HIV?

If you have unprotected sex, the amount of time you should wait before testing for HIV will differ depending on the type of HIV test you use.

ZAVA’s HIV test kit is over 99% accurate at detecting HIV if you test four weeks after possible exposure to HIV. You can test at any time before that but if you get a negative result, you should test again to make sure that your results are accurate.

If you develop flu-like symptoms like a fever or rash after having unprotected sex, you should speak to a doctor straightaway at a sexual health clinic, or if this is unavailable, at A&E. You may need to start post-exposure prophylaxis (PEP) which is medication you take after coming into contact with HIV to prevent the virus developing into an infection. You should not start emtricitabine/tenofovir until you have confirmed you’re HIV negative.

If you take emtricitabine/tenofovir, you should get an HIV test every three months to make sure you’re still HIV negative.

Why is it important to know my kidney function before and during PrEP therapy?

Emtricitabine and tenofovir are usually passed out in your pee through the kidneys. If you have problems with your kidneys, the drugs can build up in your body to unsafe levels and cause damage.

You should check your kidney function before you start on emtricitabine/tenofovir, and afterwards once a year.

If you’re over 40 years old and have diseases that are known to affect the kidneys like diabetes and high blood pressure, you should do a kidney function test every six months.

If you have a low risk of getting HIV, you do not need to take emtricitabine/tenofovir.

HIV positive people should not take emtricitabine/tenofovir on its own, as they may develop resistance to full HIV treatment.

If you think you have a high risk of catching HIV, and fall into one or more of the following categories, emtricitabine/tenofovir may or may not be suitable for you. You should talk to a doctor about the most appropriate way to prevent contracting HIV.

• you’re under 18
• you have liver disease
• you have kidney disease
• you have an allergy to any of the ingredients in emtricitabine/tenofovir
• you’re taking any other type of antiviral medication
• you’re taking a regular high dose of painkillers
• you have any rare conditions relating to lactose intolerance
• you’re on a low phosphate diet
• you’re pregnant, breastfeeding, or trying to have a baby

Emtricitabine/tenofovir are antiviral drugs that work by protecting the body’s immune cells from HIV. The medication stops the virus from growing and spreading to other body cells.

Is emtricitabine/tenofovir safer than condoms?

Emtricitabine/tenofovir only protects you from HIV. Using a condom is a much safer option as condoms offer protection from a range of STIs, as well as HIV.

It’s recommended that you get tested for STIs every three months, including an HIV test.

Is undetectable HIV safe?

Studies have shown that people with an undetectable HIV viral load (the amount of the virus in their blood is not able to be found) cannot pass on the virus to others.

The PARTNER 2 study found that people taking effective HIV treatment and had an undetectable viral load, did not pass on the virus to their sexual partners.

Is emtricitabine/tenofovir effective after exposure?

If there’s a chance you’ve come into contact with HIV and you’re taking emtricitabine/tenofovir as prescribed it should offer protection from becoming infected.

If you’ve been exposed to HIV, and you’re not currently taking emtricitabine/tenofovir, you should not start taking it. You should go to a sexual health clinic, or if not available, A&E. You may need to start taking post-exposure prophylaxis (PEP).

It's important to take the drugs as prescribed by your doctor and to read the patient information leaflet that comes with the pack of medication.

ZAVA prescribes emtricitabine/tenofovir to be taken daily. It’s best to take each tablet with food, at the same time each day.

What dose of emtricitabine/tenofovir should I take?

We offer 200mg emtricitabine and 245mg tenofovir, to be taken daily.

How long does emtricitabine/tenofovir take to work?

It takes about four days for emtricitabine/tenofovir to start working in men and up to seven days for women.

How long does emtricitabine/tenofovir stay in your system?

It’s not yet known exactly how long emtricitabine/tenofovir can stay in the body after stopping therapy, but research has estimated up to seven days.

What should I do if I miss a dose of emtricitabine/tenofovir?

If you forget to take emtricitabine/tenofovir and remember within 12 hours of when you usually take it, you should still take the next dose. If you remember later than 12 hours of when you usually take it, you should leave it and take the next dose as usual the next day.

What should I do if I take too much emtricitabine/tenofovir?

If you take more than your prescribed emtricitabine/tenofovir dose, you should go to your nearest sexual health clinic for advice, or call 111.

Can I drink alcohol while I’m taking emtricitabine/tenofovir?

Emtricitabine/tenofovir is not known to cause any interactions with alcohol, so you can still drink while taking emtricitabine/tenofovir.

As with all medicines, emtricitabine/tenofovir can have side effects. Most people do not have any, and for those that do, they usually go away within a few weeks.

Common side effects of emtricitabine/tenofovir include:

• feeling sick and being sick (vomiting)
• diarrhoea
• headaches
• dizziness
• feeling weak
• pain in the stomach
• feeling bloated
• problems with sleeping
• rashes or swelling of the skin

Less common side effects include:

• anaemia (a lack of red blood cells, or haemoglobin, in the blood)
• muscle weakness and pain
• yellow and itchy eyes
• pain in the bones
• joint stiffness
• back pain
• a condition called lactic acidosis where lactic acid builds up in the body causing drowsiness and difficulty with breathing

If you experience any serious side effects, you should go to A&E immediately.

It’s important to tell your doctor about any medicines you’re taking, including over-the-counter drugs, before you start on a course of emtricitabine/tenofovir.

Some medications may affect emtricitabine/tenofovir and cause problems with your kidneys. Talk to your doctor if you’re taking:

• any drugs for treating fungal infections
• any drugs for treating viral infections
• antibiotics
• painkillers like Ibuprofen
• medications for treating hepatitis C
• cancer drugs