PrEP explained: A guide

Written in association with:

Dr Emily Lord

GU doctor

Published: 22/11/2023
Edited by: Kate Forristal

---

In her latest online article, Dr Emily Lord gives us her insights into PrEP. She talks about what it is, how it works, who should take it, side effects, how to take PrEP, monitoring and how to access PrEP.

 

What is PrEP?

PrEP stands for Pre-Exposure Prophylaxis. It is a medication that can be taken every day or just before sex, which helps reduce the risk of a person catching a HIV infection. It is a combination of two medications, combined into one tablet. These medications are usually: tenofovir disoproxil and emtricitabine (there are slightly different medications that can be used if you have certain health problems, such as osteoporosis or kidney disease).  

 

 

How does PrEP Work?

PrEP works by preventing the replication of the HIV virus in the body. If you are exposed to HIV but have taken PrEP correctly, the drug levels in your blood will be high enough to prevent HIV from spreading throughout your body. If taken correctly, it can be more than 99% effective in preventing HIV infection.

 

 

Who should take PrEP?

There are quite a few reasons why people can use PrEP to reduce their risk of sexually acquiring HIV, for example:

You are an HIV-negative man who has condomless sex with men or trans-women You have a current sexual partner who is HIV-positive, but their virus is not fully suppressed in their blood. You have condomless sex with multiple partners and do not know their HIV status. You accept money or other items such as drugs or shelter in exchange for sex.

 

 

Are there any side effects?

Most people have very few side effects. However, in the first few weeks, some patients experience mild nausea, diarrhoea, bloating and headache. Occasionally, PrEP can cause more serious side effects that reduce kidney function and/or bone health. For this reason, it is important to ensure that you have a full assessment from your doctor before you start and regular kidney monitoring.

 

 

How can you take PrEP?

There are a few different ways to take PrEP, and it is important to discuss the most appropriate regimen with your doctor before you start. You can change the way you take it, especially when your sexual risk has changed. Do get advice before you change though, to ensure you are fully protected. The table below explains the most common PrEP regimens:

 

 Regimen

 How to take

 Important to note

 

 Daily

Take 1 pill every day

Anyone can use daily PrEP  - and it is best for those having lots of high risk sex.

For vaginal or frontal sex – make sure you have taken a full 7 days of pills before you have sex.

 On Demand

Take x2 pills before sex. Ideally this should be between 2 -24 hours before sex. Take x1 pill 24 hours after the double dose. Take x1 pill the next day, 24 hours later

Can only be used for anal sex – not for vaginal or frontal sex.

 

If you are having multiple episodes of sex over a few days, take a pill every 24 hours until you have not had sex for 2 days.

 T’s & S’s

4 pills per week Usually taken on Tuesday, Thursday, Saturday and Sunday

Only suitable for anal sex, not vaginal or frontal sex.

 

 

What monitoring should you have?

It is important to ensure you have a full check-up with your doctor before you start. They will take a full STI screen and also check your kidney function. Depending on your age, other medical problems, and these baseline results, your doctor will advise how often you need your kidney function checked. Depending on your personal situation you can also be vaccinated for hepatitis A and B, as well as Human Papilloma Virus (HPV).

 

All people taking PrEP should have STI testing every 3 months. Your doctor will check for:

HIV Chlamydia and gonorrhoea Syphilis Hepatitis A/B and C (depending on your risk and vaccination status) Other tests may be taken if you have any signs/symptoms of infection

 

 

How can people access PrEP?

The availability of PrEP in the UK has expanded in recent years, making it more accessible to individuals at risk of HIV. Various clinics and healthcare providers offer PrEP, and many individuals are using this preventative measure. You can access PrEP on the NHS via sexual health clinics, or you can purchase it online. You can also see a private doctor for your monitoring, ad pay for your medications.

 

 

If you’d like to arrange an appointment with Dr Lord about your sexual health concerns, you can do so via her Top Doctors profile.