Emtricitabine/tenofovir disoproxil is a type of generic medication that’s commonly taken as pre-exposure prophylaxis (PrEP). Each tablet contains 2 active ingredients: emtricitabine (200mg) and tenofovir disoproxil (245mg). Emtricitabine/tenofovir tablets are taken to either:

• reduce the risk of getting human immunodeficiency virus (HIV) in patients who are most at risk
• treat HIV alongside other medications – these tablets cannot treat HIV on their own and a doctor needs to prescribe the right HIV treatment for you

Please note, we only prescribe emtricitabine/tenofovir disoproxil as pre-exposure prophylaxis (PrEP). If you’ve been diagnosed with HIV, please speak to a specialist for treatment.

What is Truvada?

Truvada is a branded version of emtricitabine/tenofovir tablets, so these are sometimes called ‘generic Truvada’. Truvada was the first drug used to prevent HIV and can now be bought branded and unbranded.

Truvada and generic Truvada work in the same way and contain the same active ingredients. The main difference is the manufacturer and the price, as generic tablets tend to be cheaper than branded ones.

Emtricitabine and tenofovir belong to a medication group called nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). NRTIs interfere with an HIV enzyme called reverse transcriptase by changing the shape of the copying mechanism. The virus needs this enzyme to accurately reproduce itself and spread throughout your bloodstream. By stopping this action, HIV isn’t able to replicate. Emtricitabine/tenofovir disoproxil is most effective at doing this when taken as prescribed, without missing a dose.

How long does emtricitabine/tenofovir disoproxil last?

The half-life of emtricitabine/tenofovir is between 12 and 18 hours. This is how long it takes for half of the active ingredients to leave your body. When taken daily, it’ll keep protecting you from HIV until your next dose is due.

How long does emtricitabine/tenofovir disoproxil take to work?

It can take emtricitabine/tenofovir 4 days to work if you have a penis, after this you’ll be protected. It takes 7 days for emtricitabine/tenofovir to work if you’ve got a vagina or cervix. If you think you may have sex before this, speak to your doctor. For anal sex they may recommend taking 2 emtricitabine/tenofovir tablets at least 2 hours before sex then continuing with your treatment as normal.

PrEP has been shown to reduce your risk of getting HIV by up to 97%, but this depends on many other factors, such as whether:

• your sexual partner is HIV-positive
• you’re using a condom
• you’re taking your emtricitabine/tenofovir tablets correctly (as prescribed and without missing doses)

The PrEP Impact Trial, a study that ran from October 2017 to July 2020 involving over 24,000 patients, found that PrEP reduced the risk of getting HIV on average by 86%. PrEP was also found to “considerably reduce HIV acquisition in real-world settings across several years of use”.

Will emtricitabine/tenofovir stop me from getting HIV?

Emtricitabine/tenofovir can significantly reduce your risk of getting HIV, but the best chance of preventing HIV is to follow these practices while taking it:

• use condoms to reduce contact with blood, vaginal fluids, or semen
• get tested for HIV and other STIs regularly – infections such as gonorrhoea and syphilis can make it easier to catch HIV
• don’t share items that could have body fluids or blood on them, such as razor blades or toothbrushes
• don’t share or re-use needles or other drug equipment when injecting drugs

To get emtricitabine/tenofovir prescribed through our service we’ll need to check that you:

• have normal kidney function – our PrEP service includes a kidney function home test
• are over 18 years old
• don’t have HIV – you’ll need a negative HIV test, as PrEP won’t work if you already have HIV. You should also regularly test for HIV during treatment.
• don’t have hepatitis B (if you’ve not been vaccinated)
• don’t have hepatitis C if you’re a man who has sex with men, or you’re a trans woman

It’s unsafe to take emtricitabine/tenofovir tablets without testing for these first.

Should I be taking PrEP?

You can check with your doctor if you should be taking emtricitabine/tenofovir (PrEP), but it’s recommended if you’re HIV-negative and:

• are a man who has sex with other men without condoms
• have a sexual partner (or ex-partner) who’s been diagnosed with or is being tested for HIV, even if they’re taking HIV medication – if your sexual partner takes treatment and has an undetectable viral load, you may not need to take PrEP
• have a sexual partner who comes from a country with high rates of HIV, such as South Africa, Mozambique, India, or Nigeria
• have sex without condoms with any person who doesn’t know their HIV status
• are a trans or non-binary person and have sex without condoms
• exchange sex for drugs, money, or any other reason
• inject drugs

If you want to take emtricitabine/tenofovir and fall under any of these categories, speak to a healthcare professional, such as one of our doctors. You can buy emtricitabine/tenofovir disoproxil 200mg/245mg online through our confidential and discreet service, as well as get tested for HIV.

Always take emtricitabine/tenofovir as your doctor has prescribed it. The recommended dose for PrEP is 1 tablet every day, preferably with food. You can also take PrEP ‘on demand’, which means only taking it before and after sex to reduce your HIV risk. Our doctors recommend daily use, as this has been proven to be most effective at reducing HIV risk.

If you have difficulty swallowing tablets, you can crush emtricitabine/tenofovir:

• Use the tip of a spoon to crush the tablet.
• Mix the powder well with around 100 ml (half a glass) of water, or grape or orange juice.
• Drink immediately.

If you’re sick (vomit) within an hour after taking your emtricitabine/tenofovir tablet, take another tablet. You don’t need to take another tablet if it’s been over an hour.

When to take emtricitabine/tenofovir disoproxil

You can take emtricitabine/tenofovir at any time of day, as long as you take it everyday. Stick to around the same time to keep the medication levels steady in your bloodstream and to make it easier to remember.

How often should I take emtricitabine/tenofovir disoproxil?

Emtricitabine/tenofovir for PrEP should normally be taken daily. Continue taking emtricitabine/tenofovir every day, not just when you think you might be at risk of getting HIV. Stopping and starting your treatment can make it less effective.

How long do you need to take emtricitabine/tenofovir disoproxil for?

You can take emtricitabine/tenofovir for as long as you need it. Stopping your treatment can increase your risk of catching HIV, so you should discuss all options with your doctor first.

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

If you miss a dose of emtricitabine/tenofovir and it’s been:

• less than 12 hours: take your tablet straight away, then continue taking your treatment at your usual time.
• 12 hours or more: skip the missed dose and wait until your next dose is due. Don’t take 2 tablets to make up for a missed dose.

Missing a dose of emtricitabine/tenofovir can make it less effective, so it’s important to take it every day. Set an alarm or reminder on your phone to help you remember. You might want to take extra precautions, such as using a condom if you miss a dose, until you’ve taken your tablets again for 7 days continuously.

Like all medications, emtricitabine/tenofovir can have side effects although not everyone will get them. A doctor will assess your suitability before starting PrEP to make sure it’s safe for you to take.

There are some possible serious side effects of emtricitabine/tenofovir. If you notice any of the following, this is a medical emergency and you should get to a hospital or call 999 straight away:

• lactic acidosis (excess lactic acid in your blood) – this happens more often in women who are overweight, or in people who have liver disease. Symptoms include drowsiness, deep, rapid breathing, feeling sick (nausea), being sick (vomiting), and stomach pain.
• autoimmune disorders – this happens when the immune system attacks healthy body tissue. Look out for symptoms of an infection or other symptoms, such as weakness in the muscles or at the hands and feet which moves towards the trunk of your body, hyperactivity, tremors, or heart palpitations.

Very common emtricitabine/tenofovir disoproxil side effects include:

• diarrhoea
• nausea
• vomiting
• headache
• dizziness
• rash
• feeling weak

Tests may also show:

• a decrease in phosphate
• an increase in creatine kinase

Common emtricitabine/tenofovir disoproxil side effects include:

• pain
• stomach pain
• difficulty sleeping
• abnormal dreams
• problems with digestion which can result in discomfort after eating, feeling bloated, and flatulence
• rashes, including red spots or blotches with blistering and swelling of the skin, which may be allergic reactions
• itching
• changes in skin colour, such as darkened patches
• other allergic reactions, such as wheezing, swelling or feeling light-headed

Tests may also show:

• low white blood cell count, which can make you more prone to infection
• an increase in triglycerides, bile, or sugar in your blood
• liver and pancreas problems

Uncommon emtricitabine/tenofovir disoproxil side effects include:

• anaemia (low red blood cell count)
• pain in the stomach caused by pancreatic inflammation
• swelling of the lips, tongue, throat, or face
• a breakdown in muscle, muscle weakness, or pain – this may be a sign of damage to the kidneys tubule cells

Tests may also show:

• changes in urine
• decreased potassium levels
• increased creatinine

If you notice any of the above emtricitabine/tenofovir side effects, speak to your doctor straight away if they’re serious, aren’t going away, or are affecting your daily life.

Rare emtricitabine/tenofovir disoproxil side effects include:

• fatty liver
• liver inflammation, which can cause yellowing of the skin or eyes, pain in the stomach, and itching
• kidney inflammation, failure, or damage, with symptoms such as pain around the stomach area, feeling thirsty, and passing a lot of urine
• bone softening, which may cause bone pain and an increased risk of fractures
• back pain caused by kidney problems

These side effects are serious, so call 999 or go to A&E straight away if you notice any of the above symptoms.

The following side effect has been reported while taking emtricitabine/tenofovir, but there isn’t enough data to estimate how commonly it occurs:

• bone problems – some patients may develop a bone disease called osteonecrosis, which is death of the tissue caused by a loss of blood supply to the bone. This is more likely if you’re taking these tablets for a long time, taking corticosteroids, have a weakened immune system, drink alcohol, or are overweight. Symptoms include difficulty moving, stiffness, aches, and pains in the joints, especially in the knee, hip, or shoulder.

How long do emtricitabine/tenofovir disoproxil side effects last?

Most side effects only last a few days to a few weeks and are mild in nature. You can get emtricitabine/tenofovir side effects at any time, even after taking the medication for a long time. If side effects are serious or last longer than a few weeks, speak to your doctor straight away.

What to do if you get emtricitabine/tenofovir disoproxil side effects

Emtricitabine/tenofovir side effects can usually be managed at home by:

• taking your tablet with food to reduce the risk of stomach pain, nausea, and vomiting
• taking over-the-counter painkillers for pain and headaches
• staying hydrated
• avoiding alcohol and recreational drugs, if you’ve got side effects
• eating small, light meals rather than heavy, greasy, spicy, or fatty meals
• using an anti-nausea or anti-diarrhoea medication
• getting plenty of rest
• talking to your doctor, if you can’t manage them on your own or they’re getting worse

Don’t take emtricitabine/tenofovir tablets if you’re allergic to any of the active or non-active ingredients in the tablets.

Although you need to take an HIV test before starting emtricitabine/tenofovir, you should let your doctor know straight away if you notice any of the following symptoms of HIV during your treatment:

• headache
• rash
• tiredness
• fever
• muscle or joint aches
• vomiting or diarrhoea
• night sweats
• enlarged lymph nodes in the groin or neck

Emtricitabine/tenofovir tablets need to be taken daily. Missing doses could increase your risk of HIV, so you should use a condom or abstain from sex until you’ve taken your tablets for at least 7 days in a row.

Speak to your doctor before taking emtricitabine/tenofovir if you’ve got:

• kidney problems, especially severe kidney disease or if you receive dialysis – you may not be able to take this medication
• bone problems, such as osteoporosis – this medication can cause bone problems and may not be suitable
• a history of liver disease, such as hepatitis
• an intolerance to lactose, as this is an ingredient in the medication

This medication hasn’t been studied in patients over 65 so may not be suitable.

Pregnancy and breastfeeding:

• Speak to your doctor if you’re pregnant, think you might be pregnant, or are planning a pregnancy. The prevention of HIV during pregnancy usually outweighs any risk to the baby but your doctor may want to monitor you and your baby closely.
• Don’t breastfeed your baby while taking this medication as it can pass through your breast milk.

Emtricitabine/tenofovir disoproxil and other medications

Don’t take emtricitabine/tenofovir disoproxil if you’re taking any other antiviral medications containing:

• emtricitabine
• tenofovir disoproxil
• tenofovir alafenamide
• lamivudine
• adefovir dipivoxil

Taking emtricitabine/tenofovir disoproxil with certain medications can cause damage to your kidneys, so let your doctor know if you take any other medication, especially:

• aminoglycosides or vancomycin for bacterial infections
• amphotericin B for fungal infections
• foscarnet, ganciclovir, or cidofovir for viral infections
• pentamidine for infections
• interleukin-2 for cancer treatment
• non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen
• ledipasvir/sofosbuvir, sofosbuvir/velpatasvir, or sofosbuvir/velpatasvir/voxilaprevir for hepatitis C

Emtricitabine/tenofovir disoproxil with food and drink

You can eat and drink normally while taking emtricitabine/tenofovir tablets. It’s also recommended to take your tablet with a meal or snack. You can drink alcohol, but it might be best to avoid it if you get side effects, until they go away.

The most common type of PrEP in the UK is emtricitabine/tenofovir disoproxil. You can also be prescribed with Truvada, which is the branded version of the same medication with the same active ingredients.

There’s also a second pill that’s been approved for reducing HIV risk in the UK with similar ingredients: Descovy. This either comes as a branded treatment or as a generic treatment and contains the active ingredients tenofovir alafenamide and emtricitabine. We don’t currently offer Descovy but you may be able to get it on the NHS.

There’s also a long-acting PrEP injection that’s been approved in the US but isn’t currently available in the UK.

Can I buy emtricitabine/tenofovir disoproxil over the counter?

No, emtricitabine/tenofovir disoproxil tablets are a prescription-only treatment, as you need to meet certain requirements to take them. It’s not safe to take this medication if you’ve got certain medical conditions and you need to be HIV-negative to get PrEP.

Can I get emtricitabine/tenofovir disoproxil on the NHS?

Yes, emtricitabine/tenofovir disoproxil is available on the NHS. You’ll need to speak to your GP or go to an NHS sexual health clinic.

Is emtricitabine/tenofovir disoproxil effective after exposure?

Emtricitabine/tenofovir disoproxil is a PrEP treatment, so it can help prevent HIV if you’re exposed to it while taking it. It won’t work if you’ve already been exposed to HIV. Instead, you’ll need post-exposure prophylaxis (PEP) which you can get at a sexual health clinic.

Is emtricitabine/tenofovir disoproxil safer than condoms?

Emtricitabine/tenofovir disoproxil isn’t more or less safe than condoms. It can lower your risk of catching HIV just like condoms can, but both methods are most effective when used together. Also, condoms can prevent more STIs than just HIV and some of those STIs can make catching HIV more likely.