Pre-exposure prophylaxis (PrEP) is the use of antiretroviral medication (specifically Tenofovir/Emtricitabine) to reduce the risk of acquiring HIV. If taken every day this medication significantly reduces your chance of acquiring HIV.
It is important to consider both the benefits and risks of starting PrEP. If you are to start, make sure that you are doing it for your own reasons, rather than for anyone else’s benefit.
It is important that you evaluate your own risk of acquiring HIV, or if you’re unsure, to speak to a sexual health clinician. While PrEP is a highly effective strategy in preventing HIV, there are other highly effective strategies out there, including U=U and condoms.
Prior to starting PrEP, the clinician will test you for your HIV status, if you have any symptoms of a new HIV infection, your other STIs and Hepatitis status, as well as your kidney function levels. PrEP also requires ongoing kidney function monitoring on a three-monthly basis, as it can take a toll on your kidneys. This is done when you come in for a PrEP follow-up to receive your three-monthly script.
Frequently Asked Questions about PrEP:
What is PrEP?
PrEP stands for pre-exposure prophylaxis. PrEP is taken before sex, so it is pre-exposure. Prophylaxis means to prevent infection. So HIV negative people can use PrEP to significantly reduce the chances of them from becoming HIV positive. PrEP is very effective at preventing the transmission of HIV. If taken on a daily basis without missing any doses, it can be more than 99% effective.
Currently, PrEP uses oral tablets that include two drugs: both tenofovir DF (TDF) and emtricitabine (FTC). The main brand name for this is Truvada, but generic (non-branded) versions are also available.
Both TDF and FTC have been widely used to treat HIV. PrEP was approved in the US in 2012 and in Europe in 2016. PrEP became available on the PBS (Pharmaceutical Benefits Scheme) in Australia in April 2018
Who would benefit from taking PrEP?
PrEP is used to protect you from contracting HIV. Therefore, anyone who perceives that they are at risk of contracting HIV is suitable to take PrEP.
Please remember that anyone who is HIV positive and is taking medication regularly and is UNDETECTABLE means that they are not a risk for infection. UNDETECTABLE = UNTRANSMISSABLE
U = U
If you are HIV negative and don’t always use condoms, then PrEP could reduce your risk of HIV. Other factors related to a higher risk of HIV include:
- A recent STI (especially rectal infection or syphilis).
- Recent need for PEP (post-exposure prophylaxis).
- Using recreational drugs used for chemsex (crystal meth, mephedrone and GHB).
- If your HIV positive partner is finding it difficult to be adherent to their HIV meds.
Please speak to your doctor or nurse about how these risks affect you.
Is there anyone who should not take PrEP?
PrEP should NOT be used:
- By people who are HIV positive.
PrEP is usually not needed if:
- The negative person only has HIV positive partners who are on ART with undetectable viral load. An undetectable viral load means that an HIV positive person is not infectious.
- If you are happy and able to always use condoms.
How well does PrEP work?
PrEP is highly effective at reducing the risk of HIV infection. PrEP works extremely well if taken correctly. As stated previously, PrEP is over 99% effective at protecting you from HIV infection if taken every day without missing any doses. Some people may choose to take PrEP in an “on demand” or event drive way the efficiency can drop to around 86%.
Does PrEP have any side effects?
The majority of people taking PrEP do not get side effects.
However, like all other medicines, PrEP has the potential to cause side effects. In studies, mild nausea, diarrhoea, bloating and headache were reported in the first month by less than 1 in 10 people. These side effects then usually stop.
Occasionally, PrEP can cause more serious side effects that reduce kidney function and/or bone health. This is why monitoring blood tests are used before and during treatment.
Can taking PrEP lead to HIV resistance?
If you take PrEP correctly, the chance of drug resistance is very low.
Firstly, resistance relates to HIV and not the person. So an HIV negative person can’t be resistant. Secondly, resistance is only a risk if you become HIV positive. Even then the risk is low.
The risks of drug resistance are from:
- Starting PrEP without knowing that you are already HIV positive. This is why the HIV test before PrEP is essential.
- Becoming HIV positive during a break from PrEP and then not having an HIV test before restarting.
- Missing too many PrEP doses, so that drug levels are too low to prevent HIV infection.
- Contact with drug-resistant HIV. This is very rare: globally, only two cases have been reported of PrEP not working because of drug-resistant HIV.
Does PrEP work with any other STIs (or STDs)?
PrEP does not protect against other STIs. Condoms can help prevent against many other STIs. Although STIs are mostly easy to treat, symptoms can sometimes be unpleasant and sometimes serious. This is why regular testing for STIs is a good idea.
Make sure you are protected from as many infections as possible. Hepatitis A + B vaccinations are available and are usually recommended if you are taking PrEP. The HPV vaccine can protect against genital warts and cervical/anal cancers. It is available for some gay men but there may be a charge.
Does PrEP interact with other medicines?
PrEP does not interact with most other medicines. But if you are prescribed other meds, always tell your doctor (including your GP) that you are taking PrEP. You can also ask a pharmacist to check for drug interactions, including with over-the-counter meds.
One important exception is that TDF does interact with some non-steroidal anti-inflammatory drugs (NSAIDs), especially diclofenac. Taking both drugs together can cause kidney problems. Other NSAIDs include ibuprofen and naproxen. Avoid using these meds if you are taking PrEP, or let your doctor know if you need to take them.
Info on interactions between PrEP and other meds, including hormone treatment is on this site from Liverpool University: www.hiv-druginteractions.org. There is also a free app that is downloadable on most phones – search for ‘Liverpool HIV iChart’.
I want to start PrEP! What do I need to do first?
1. First, please talk to your doctor at the clinic. To help you decide if you want to take PrEP, or are already taking it.
2. It is important to have an HIV test before or as you start PrEP as it can only be used if you are HIV negative. If you are already HIV positive and don’t realise it, you could develop drug resistance. Ask for a ‘4th generation’ HIV blood test. This is also called a ‘antigen/antibody’ test. This tells you your HIV status roughly four weeks ago. Most finger prick tests are currently ‘3rd generation’. They tell you your HIV status 2-3 months ago. So don’t rely on a finger prick test before you start PrEP, if you have a more recent risk.
3. Be careful about starting PrEP if you have flu-like symptoms and had a recent HIV risk. This is in case these symptoms are related to a recent HIV infection.
4. Check your kidneys
Kidney tests just involve a blood test for creatinine. Sometimes it also includes a urine test for protein. These tests should ideally be done just before or on the day you start.
5. Check for other sexually transmitted infections (STIs)
HIV and STI tests are a great idea for anyone with an active sex life. This is whether you use PrEP or not. Test for hepatitis B (HBV) Testing for hep B is essential. This is because PrEP meds are active against both HIV and HBV. This is a good time to have this vaccine, or to boost a previous vaccine.
You can still use PrEP if you have HBV, but it needs to be used more carefully. People with HBV need to take PrEP every day, with medical advice, especially if you want to stop.
OK so I’ve started PrEP! What next? What do I have to keep doing?
Once you have started PrEP, monitoring is just as important. You need to have a check-up 1 month after commencing PrEP to ensure your kidneys are coping with the medication, also to have a repeat HIV test. Following this you should have a check-up every 3 months, no matter what type of dosing regimen you use. If you are currently using PrEP and have not been monitored, talk to the clinic about doing this now.
Every 3 months:
- Have a ‘4th generation’ HIV blood test. This is also called and ‘antigen/antibody’ HIV blood test.
- Have a full screen for other STIs.
- Have a urine test for protein when you have your STI check up
- Have a blood test to check your kidney function.
- Test for hepatitis C.
How do I take PrEP?
Most PrEP studies have used daily PrEP. It is the recommended way of taking it with one tablet every day at roughly the same time of day.
Taking PrEP every day will make sure that there are protective drug levels 24 hours a day, 7 days a week. This means you do not have to plan PrEP for when you might have sex. If you generally have sex every week, daily PrEP has the advantage of being an easier routine.
It works best when you take it daily for 7 days before you start engaging in condomless sex. This allows your body to have enough of a dose of PrEP in your system to work effectively.
What do I do if I miss a pill?
Missing one dose is unlikely to cause any problems. If you miss one, this will be fine. Don’t stop PrEP, just carry on once you remember. Drug levels will still be high enough to protect against HIV. If you are missing several doses each week, please talk to the clinic about support.
If you use daily dosing and miss more than a week of pills, then restart with a double dose (two pills) and then continue with one pill a day. Never take more than one double dose when you start PrEP. You only need one double dose at the start. More than one double dose in a week may be harmful. Do not take more than a total of seven pills in one week.
- Pick a regular time and try to stick to this each day. Link it to a routine task like brushing your teeth. It doesn’t have to be the exact same time but it will help get you into a routine.
- If you have a break from PrEP and have risks during this time, it is important to have another HIV test.
Can I stop PrEP?
Stopping PrEP is OK as long as it is done safely. You must continue to take PrEP every day until 2 days after your last exposure to any risk. So, if you have sex without a condom you need to take PrEP for a further 2 days (2 further tablets) in order to be protected. After this you can stop if you are not going to be having sex for some time. When you start taking PrEP again, remember to take 2 tablets at least 2 hours prior to having any sexual activity.
You might decide that you want to stop PrEP altogether. Discuss your decision to stop with your doctor. You might want to discuss plans to stop PrEP with partner(s) and get tested for HIV and other infections together.
Make sure you use a 4th generation HIV test four weeks after the last risk.
If in the future your circumstances change again, it is easy to restart PrEP. If you stop PrEP and have a risk afterwards, contact your clinic in case post-exposure prophylaxis (PEP) might be needed. In the cases when PEP is used, it needs to be started as soon as possible.