HIV PrEP (pre-exposure-prophylaxis)

PrEP, or 'pre-exposure-prophylaxis', is a new preventive method against HIV.

About PrEP

PrEP is short for 'Pre-Exposure-Prophylaxis'. The concept is familiar to other preventive methods:

  • Women take the contraceptive pill before having sexual contact.

  • People take antimalarial pills before travelling to malaria endemic countries.

  • People get vaccines to avoid getting sick. Vaccines are in that way also a type of PrEP.

In the case of HIV PrEP, HIV negative people take HIV inhibitors to prevent contracting an HIV infection. However, PrEP does not guarantee full protection against HIV, least of all against other STIs.

There are many points to consider. Read the following information carefully if you're considering taking PrEP. Revisit this page if you still have questions after starting your PrEP intake. Consult our FAQ down below for up-to-date, important information.

Make an appointment

Individuals interested in starting PrEP should come by our clinic to discuss possibilities. PrEP users should also consult with a doctor every three months for a regular check-up and to receive the necessary prescriptions.

Make an appointment

PrEP intake

There are two different schemes for PrEP intake: daily and periodic.

Only men should follow the periodic scheme of PrEP. Women and trans women taking hormones should follow the daily scheme, or a scheme that schedules PrEP intake for at least 7 days prior and 7 days after sexual contact.

Periodic PrEP use


Take a minimum of four pills in the course of three days:

  • Take two pills no later than two hours prior to having sexual intercourse (and no earlier than 24 hours prior to having sexual intercourse).

  • Then take one pill after 24 hours and one pill after 48 hours after the last sexual contact.

  • Never discontinue your intake during a cycle!


  • Pills must be taken at the same time as the first one, within a time frame of four hours (from two hours prior to two hours after).

  • If you vomit within 30 minutes after intake, take a new pill.

  • Did you take your pill too late (more than two hours after the starting time) and have you been at risk for HIV?

    • Start PEP intake as soon as possible (within 72 hours, only if PrEP was not taken (properly))!

Daily PrEP use


Take one pill a day, always at the same time, within a time frame of four hours (from two hours prior to two hours after the exact time).

Tip: Pick a convenient time of day in which you are less likely to forget, both during the week and in the weekend.


  • You are most protected two hours after taking the second pill (in other words: 26 hours after the first). For women, optimal protection comes after seven days!

  • Did you take your pill too late?

    • Less than 12 hours late: take the pill immediately!

    • More than 12 hours late: wait until the next (normal) time. Be aware that your PrEP level is temporarily lower than it should be. Do not take any risks!

PrEP dagelijkschema
PrEP periodiek schema

Interactions between PrEP and other medicines

There is one important interaction between PrEP and anti-inflammatory drugs, especially:

  • diclofenac (e.g. Voltaren)

  • ibuprofen

  • naproxen (causes kidney problems)!

Combination with paracetamol (e.g. Dafalgan) is okay.

Source: HIV Drug Interactions Checker (University of Liverpool)

Tips on taking PrEP

  • Set alarms on your smartphone.

  • Use a pill box to organise your medication weekly.

  • Use a free app on your smartphone:

    • Medisafe (medication reminder)

    • MyTherapy

    • Tabtime Vibe Vibrating Pill Timer Reminder

Other notes

  • PrEP does not guarantee full protection against HIV, least of all against other STIs!

  • Your mutual insurance company will send you the approval for medication by mail. You can go to the pharmacist with your eID and your prescriptions (90 pills cost app. € 15).

  • Every 3 months, you must return to ITM's clinic for a check-up and your prescriptions. Don't forget to make an appointment well in advance.

  • Should you have sexual problems or problems related to chemsex, it's always possible to see a sexologist at ITM for free. Ask for an appointment at the reception desk, or with your nurse or doctor.

Frequently Asked Questions (FAQ) on PrEP

What is PrEP?

PrEP stands for 'Pre-Exposure-Prophylaxis'. The concept is familiar from other situations: women take the contraceptive pill before sexual contact.

If you are travelling to a malaria country, you start your anti-malaria pills before you leave. Vaccines are also a kind of PrEP: you get vaccinated so as not to get sick. For HIV: HIV-negative people take HIV inhibitors to prevent HIV infection.

PrEP only protects against HIV

Taking PrEP will not protect you from other STIs (sexually transmitted infections). So the message is clear. PrEP does not replace the use of condoms, it is added as a prevention tool. You can still get other STIs if you take PrEP and stop using condoms.

PrEP protects against HIV if you take the pills!

Very solid scientific research and clinical trials show that PrEP intake significantly reduces the risk of HIV infection in people who took the medication correctly. It sounds simplistic but it is true: PrEP only works if you take your pills correctly.

PrEP works, but HIV infection is still possible!

That sounds contradictory. We all know that taking pills on a strict schedule is extremely difficult, especially if you have to keep it up for a long period of time. The scientific research shows that PrEP gives a very high protection rate, over 90%, if the pills are taken correctly.

But outside the context of scientific research, the follow-up and support is less intensive. So in 'real life', there is a chance that you will forget the PrEP pills, not always take them according to schedule, or for some reason cannot get a new supply in time. And then, of course, the protection is a lot less.

What do PrEP pills look like?

Currently, only Truvada® is recommended as PrEP. It is one pill that contains two HIV inhibitors: Tenofovir and Emtricitabine.

Advantages and disadvantages of PrEP

There are advantages to PrEP, absolutely! The chance of contracting HIV is much lower.

A possible disadvantage: PrEP does not protect against other STIs. Some STIs are difficult to treat and most can go undetected with possible long-term complications.

Some PrEP researchers have found that people use condoms less and are therefore more susceptible to contracting other STIs. On the other hand, they hear stories about people who are just more aware of sex and therefore use condoms more.

There are also social drawbacks to PrEP. Some people have prejudices about PrEP. "People on PrEP would become sexually disinhibited and certainly not use condoms anymore," is one idea that is prevalent.

You can also look at it another way: people take PrEP to deal with their health in a positive way. Often, PrEP intake will also be temporary. You could also call it a positive bias: people go to a counsellor/doctor to stay healthy, in this case by taking PrEP pills.

A good remedy for PrEP prejudice is to understand the scientific basis of PrEP. Then it becomes a subject like any other. You then realise above all: it works! It is a positive contribution to HIV prevention for a very specific group of people. When the contraceptive pill was introduced in the 1960s, there were also a lot of prejudices about it. Women were said to be completely disinhibited. Surely you can't give that to women!

Another disadvantage: PrEP pills can have unwanted side effects.

Why do I need to see a doctor to receive PrEP?

Our government has decided to reimburse PrEP from 1 June 2017. They are attaching a number of conditions to it: the PrEP will be subject to strict reimbursement criteria and PrEP users must be closely monitored in HIV Reference Centres.

PrEP pills are indeed no sweets. We also know from experience that people have many questions about PrEP: Does it work? How to take it? How long will I be protected after taking it? Tips for not forgetting the pills? How to protect myself against other STIs? How to get the pills? How often should I take them?

This is best done in a personal conversation with a doctor and/or a specialised nurse.

Are you already infected with HIV?

We have to be sure that you are not already infected with HIV. PrEP consists of two HIV-inhibitors. Two HIV inhibitors are certainly not enough to suppress the HIV virus if you already have HIV without knowing it. Therefore, you should first have an HIV test with your doctor.

Kidney damage due to PrEP

PrEP HIV inhibitors can cause side effects including a type of 'kidney irritation'. Kidney damage is possible, but rarely permanent if detected in time. If you stop taking Truvada® it will disappear again. The doctor does regular laboratory tests to detect side effects. PrEP experts advise against taking high doses of anti-inflammatories (medical term: NSAIDs) together with Truvada®. Anti-inflammatories can also cause kidney problems.

STI/HIV tests

Other sexually transmitted diseases are also checked regularly: HIV, chlamydia, gonorrhoea, hepatitis C, syphilis, ...

How can I obtain PrEP pills?

Since 1 June 2017, a certain category of people can obtain PrEP in HIV Reference Centres.

The category eligible for PrEP is strictly defined based on an assessment of HIV risk. It is best to find out if you are eligible for PrEP by talking to a doctor.

Online ordering is not legally permitted in Belgium.

What does PrEP cost?

A box of 90 tablets of PrEP currently costs € 363,78 in Belgium.

PrEP is reimbursed under certain conditions and costs in that case no more than € 15 per box.

How should I take PrEP pills?

Two different schedules are available if you want to take PrEP.

Schedule 1

The most studied schedule is the daily intake. This means taking PrEP every day, without interruption. People who never forgot to take their pills had a very high protection rate in clinical trials. 1 tablet of Truvada® per day, at the same time.

Schedule 2

Under certain circumstances, intermittent intake may be considered. You take PrEP only when you need it (i.e. around your sexual contacts). This is a little more complicated and you should discuss with your doctor and/or nurse which strategy suits you best. Schedule 2 is only permitted for men who have sex with men. It is not sufficiently effective for heterosexual contact.

Please note that with daily intake, the medication level is sufficiently high two hours after your second intake (from the second day onwards) to give you optimal protection against HIV.

If you choose to take them periodically, you will already be protected two hours after your first intake (from the first day)!

If you have forgotten to take the PrEP pills and you have had a risk contact: come for a PEP consultation as soon as possible at the PrEP centre where you will be followed up! If necessary, you will receive a course of PEP against HIV. PEP should be started within 72 hours after the risk moment and the sooner, the more effective! If your PrEP centre is not open, you can go to the emergency room for a starting dose (ZNA Stuivenberg in Borgerhout, UZA in Edegem or another university hospital in your neighbourhood).

Which doctors have experience with PrEP?

Doctors of Belgian HIV Reference Centres certainly have sufficient knowledge about PrEP.

You should also inform your doctor that you are taking PrEP. For example, he or she can check whether other medicines may be taken together with PrEP pills.

How can I register for PrEP?

The RIZIV imposes a quarterly follow-up in the context of the reimbursement of Truvada® for PrEP. In practice, you will see a doctor and a nurse each time.

An initial consultation is scheduled to conduct a risk analysis, explain PrEP and determine laboratory analysis for HIV and STI. The application for reimbursement of PrEP will also be sent to the advisory doctor of your mutual health insurance company.

After a few weeks you will return for a second consultation where any questions you may have will be answered and your results discussed. You will then receive prescriptions for the PreP-medication and the necessary explanation about taking the medication. You will be asked to strictly not have any sexual risk contacts for about six weeks before starting PrEP. This is to avoid starting the medication during an initial HIV infection. When starting the PrEP medication, the HIV test will also be repeated.

We will ask you to come for a check-up every three months. Each time, a blood and urine test will be done to rule out HIV and STIs and to detect side effects of the PrEP medication. You can have this done about ten days before the scheduled appointment. In that case, the results will be discussed with you during the consultation. You may also choose to have the tests done during the consultation. In that case, you will be called if there are any abnormalities.

You will be asked to complete a short questionnaire each time.

During the consultation, your risk of HIV and STIs and your tolerance of the treatment will be checked. You will also be given the opportunity to ask any questions you may have.

You can request a consultation online at ITM under the heading 'HIV/AIDS examination'. Specialised PrEP consultations are scheduled for mornings. A doctor and a nurse are available to welcome and guide you in the framework of a PrEP treatment.

Does PrEP interact with other medicines?

If people take several medicines at the same time, they can influence each other's action: enhance, reduce or render ineffective.

If your doctor, general practitioner or specialist prescribes something, he or she should check if it is compatible with the PrEP pills, Truvada®. Check the following websites for more information:

Where can I find more information about PrEP?

For more information about PrEP, please visit the following websites (in Dutch):