What Does PrEP Do? Everything You Need To Know

A doctor shares the answers to every question you've had about PrEP.
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Emtricitabine/Tenofovir, which is also known as Truvada, is a PrEP medication (pre exposure prophylaxis) that is used to help prevent HIV infections and protect the patient’s sexual health.

It is usually prescribed to those that are at a high risk of contracting HIV and it is incredibly effective at preventing the sexually transmitted infection HIV. Emtricitabine/Tenofovir contains two active ingredients: emtricitabine and tenofovir disoproxil.

What is Emtricitabine/Tenofovir?

Truvada
Emtricitabine/Tenofovir is the generic version of the branded PrEP medication Truvada. It is an antiviral medicine most commonly used to prevent HIV infections in those that are at a higher risk.

Emtricitabine/Tenofovir
This PrEP HIV treatment contains two active ingredients: emtricitabine and tenofovir disoproxil - these drugs are nucleotide reverse-transcriptase inhibitors or NRTIs for short.

Tenvir EM
The generic PrEP drugs Emtricitabine/Tenofovir (also referred to as ‘Tenvir EM’) can be used alongside other HIV medications to help control existing HIV infections. The anti-HIV medication works to decrease the amount of infection in your body which allows your immune system to work better.

Emtricitabine/Tenofovir lowers the increased risk of contracting HIV-based complications and helps to improve the quality of life for people with the HIV virus.

It should be noted that Emtricitabine/Tenofovir is a PrEP medication that should not be used on its own to control an HIV infection. If you use it on its own it will be much less effective than if it is used in conjunction with at least one other HIV PrEP treatment.

Emtricitabine/Tenofovir (PrEP) is not a cure for HIV infections. It is also not a guarantee of preventing HIV infections.

How does PrEP work?

This is provided that it is taken daily and in conjunction with safe sex practices including the use of condoms. PrEP is a combination of two medications, emtricitabine and tenofovir.

These two medications are known as NRTIs. NRTIs work by inhibiting the enzyme in the body, reverse transcriptase. This is needed for HIV to replicate in the body.

How do I use PrEP/Emtricitabine/Tenofovir (Truvada)?

PrEP Tablets
You should make sure to always read the medication guide that comes with your medication. If you have questions or if you are not sure about something then you should ask your doctor, health care provider or sexual health clinic for medical advice before you take any prescription drugs / medication.

Emtricitabine/Tenofovir tablets are to be taken orally with water as directed by your doctor. Usually, this will be once daily. If you are taking didanosine enteric-coated tablets alongside your PrEP medication then you should take them both either on an empty stomach or with a light meal. If you are taking the didanosine buffered tablets then you should take both drugs on an empty stomach.

For the best results when using Emtricitabine/Tenofovir, you should take it at evenly spaced times. To help you remember to take your medication you should try and take it at the same time every day.

In the event of vomiting within an hour of taking a tablet, another tablet should be taken. However, if vomiting occurs more than an hour after intake, there is no need for another tablet. Overdose requires immediate consultation with a doctor via 111 or the nearest sexual health clinic.

It takes 7 days for emtricitabine/tenofovir disoproxil to become effective in protecting against HIV. In the meantime, it is advisable to employ other forms of protection such as condoms. Discontinuing PrEP requires consulting with a doctor to establish safe means of going off the medication.

 

What side effects can PrEP (Truvada) have?

Emtricitabine/tenofovir disoproxil has been associated with severe side effects such as elevated lactic acid in the bloodstream (lactic acidosis), which can lead to symptoms such as stomach pain, rapid breathing, or drowsiness and autoimmune disorders like palpitations, muscle weakness, or hyperactivity. An allergic reaction is rare when taking this HIV medication. However, it should be stressed that if you experience any adverse effects, you should seek immediate medical attention by speaking to a doctor or healthcare professional.

Emtricitabine/tenofovir is not recommended if you suffer from pre-existing kidney problems. Similarly, if you are pregnant or breastfeeding and are considering emtricitabine/tenofovir as a treatment for HIV, you should speak to a healthcare provider to assess if it will be suitable for you.

Common Truvada Side Effects

  • Dizziness
  • Headaches
  • Weakness
  • Diarrhoea
  • Nausea or vomiting
  • Trouble sleeping
  • Stomach pain
  • Bloating
  • Wind
  • Rashes
  • Allergic reactions, like wheezing or swelling
  • Reduction in white blood cells

Uncommon Truvada Side Effects

  • Swelling in the lips, tongue, throat, or face
  • Muscle pain or weakness
  • Inflammation of the pancreas, causing stomach pain
  • Reduction in red blood cells (anaemia)
  • Changes in urine
  • Liver inflammation, resulting in stomach pain, itching, and yellow skin
  • Bone pain or increased fractures
  • Kidney problems

Is it safe to take PrEP (Truvada) with other antiviral medicine?

Your doctor may wish to monitor your kidney function via blood tests if you are currently taking any other protease inhibitor antiviral medicine due to the increased risk of damage your kidneys - some protease inhibitors are associated with an increased risk of high blood pressure. Always consult them before starting a HIV medicine such as Emtricitabine/Tenofovir disoproxil treatment for HIV infections.

Can PrEP (Truvada) cause erectile dysfunction?

Although emtricitabine/tenofovir isn’t typically associated with erectile dysfunction, ED is more common in men living with HIV due to added psychological and physical pressures, such as a new diagnosis, stigma, anxiety, older age or diabetes along with other issues.

Can PrEP (Truvada) be used to treat hepatitis b (HBV)?

No. Emtricitabine and tenofovir shouldn’t be used to treat hepatitis B virus (HBV) as your condition could potentially worsen after you stop taking the medication leading to complications such as liver inflammation. It is vital to consult your doctor, healthcare provider or pharmacist before starting PrEP treatment to ensure that it is suitable and safe for you.

 

Is PrEP available on the NHS?

Yes. Generic PrEP (Emtricitabine/Tenofovir) is available at NHS sexual health clinics in the UK. PrEP medication supplied by NHS clinics is also generic.
You must speak to a doctor or your healthcare provider for medical advice before taking Emtricitabine/Tenofovir tablets. They will assess your suitability for the anti HIV medication and whether your health condition requires it or if an alternative treatment would be better suited.