Before starting treatment with Truvada for PrEP, it’s important to make sure that you don’t currently have HIV or any other STIs, and that the medicine is suitable for you.

On this page, we’ll explain what you should do before starting PrEP, and also what you’ll need to do while you are taking it.

Before you start PrEP

  1. Get a full STI screen

Because PrEP is specifically intended for use in people who are HIV negative, you will be required to have a HIV test before you start taking it. There are two main reasons for this:

  • firstly, there are other treatments which are more suitable for people who are HIV positive, and will work better at suppressing the virus;
  • secondly, if PrEP is taken by someone who is HIV positive, this increases the likelihood of the virus developing a resistance to the drug.

It’s recommended that you get what’s called a ‘4th generation HIV antibody antigen’ test. Other tests for HIV might not always discover very recent infections; it can take up to three months for the antibodies detected in these tests to develop. The 4th generation test on the other hand is much more reliable at detecting recent infections (picked up in the previous 4-12 weeks).

  1. Have a repeat STI screen 4 weeks later

It’s possible for the 4th generation test to not detect very recent infections which have been picked up within four weeks prior to testing; so if your first test was negative, you should have a follow-up test four weeks later to confirm this result.

  1. Get your kidneys checked with a blood test

It’s uncommon, but possible, for PrEP to interfere with kidney function. This is more likely to occur in people who have pre-existing kidney problems, or are taking other medications which affect how the kidneys work.

For this reason, you should ideally have a blood test before you start PrEP to check that your renal function isn’t impaired in any way. You should be able to arrange this with your GP. If you’re getting PrEP from a sexual health clinic, they should be able to do this test for you.

  1. Get vaccinated

If you’re sexually active, and particularly if you’re at increased risk of HIV, you should make sure you’re up to date with all of your vaccinations. This includes the flu jab, hepatitis A and B, and HPV. This doesn’t completely eliminate the risk of contracting these viruses, but does lower it significantly.

If you haven’t been vaccinated against the above, speak to your GP.

When taking PrEP

  1. Continue to have an STI screen every 3 months

People who are taking PrEP should continue to have a full STI screen, including a 4th generation HIV test, every three months; and you’ll need to get tested this often regardless of whether you have any symptoms of an STI or not.

While the risk of getting HIV if you’re taking PrEP is very small, you’ll still need to get tested regularly to make sure you haven’t contracted the virus. Again, this is because the virus can develop a resistance to the drugs used in PrEP. Even though it isn’t likely provided the treatment is taken properly, if someone using PrEP becomes infected with HIV, they’ll need to be seen by a doctor and have their treatment switched as soon as possible.

You can arrange to have an STI test through your GP or local sexual health services. It’s also possible to order a test kit online from us.

  1. Practice safe sex

While PrEP reduces the risk of getting HIV, there are other measures you can take to further lower your risk, such as:

  • using condoms or barrier contraception
  • not sharing sex toys or other items which come into contact with bodily fluids
  • and not sharing needles.

You should still take these precautions, even if you are using PrEP.

  1. See your doctor if you notice anything unusual

Talk to your GP right away if you develop any unusual symptoms or side effects when taking PrEP, such as:

  • a high temperature
  • sickness or diarrhoea
  • muscle and joint aches
  • swollen lymph nodes
  • a rash
  • headaches
  • or increased perspiration.

If you’re unsure of anything to do with your medication, ask your GP or your pharmacist for help.

Page last reviewed:  18/02/2019