01 — The medicine
An emergency course of HIV medicine, taken for 28 days.
PEP (post-exposure prophylaxis) is a short course of antiretroviral tablets that stops HIV from establishing an infection after a possible exposure.
It works by blocking the virus from copying itself in the first hours and days, before it can take hold. That is why timing matters so much: the sooner you start, the better it works.
PEP is for emergencies. If you are regularly at risk of HIV, PrEP (pre-exposure prophylaxis) offers ongoing protection, and we can help you move from PEP to PrEP when your course is finished.
Consider PEP if, in the last 72 hours…
- A condom broke, slipped off or wasn’t used
- You had sex with someone whose HIV status you don’t know
- Your partner has HIV and is not on effective treatment
- You were sexually assaulted
- You shared needles or other injecting equipment
- You had a needle-stick or other injury involving blood
Not sure if your situation counts? Message us. A doctor will assess your real risk, and tell you honestly if you don’t need PEP.
How it works
Three medicines, one job.
PEP uses the same kind of antiretroviral medicines used to treat HIV, given early enough to stop an infection from starting.
Early
It stops the virus copying itself
In the first hours and days after exposure, HIV needs to multiply to take hold. PEP blocks that process before it can establish an infection.
Combined
It’s a combination of medicines
PEP is usually three antiretroviral medicines, often in one or two tablets a day. Your doctor chooses the right regimen for you.
28 days
It must be taken in full
PEP only works if it is taken every day for the whole 28-day course, even if you feel well or the risk seems small.
While you’re taking PEP
What to expect over 28 days.
Modern PEP is generally well tolerated. Some people have mild nausea, tiredness, headache or an upset stomach in the first days, which usually settle. If anything worries you, message us rather than stopping.
- Take your tablets at the same time every day. A phone reminder helps.
- If you miss a dose, take it as soon as you remember and contact us for advice.
- Don’t stop early, even if you feel fine. Talk to us first about any side effects.
- Tell the doctor about all medicines and supplements you take. Some antacids, iron and calcium can interfere with PEP.
- Use condoms during the course and until your follow-up tests are clear.
PEP or PrEP?
Before or after: the difference.
| PEP | PrEP | |
|---|---|---|
| When | After a possible exposure | Before exposure, ongoing |
| Start | Within 72 hours, ideally 2 | Any time you are HIV-negative |
| How long | 28 days | As long as you are at risk |
| Best for | Emergencies | Regular protection |
Effectiveness
How effective is PEP, and what helps it work?
What is HIV PEP able to do? Started early and taken every day for 28 days, it greatly reduces the chance that a possible exposure leads to HIV, but it cannot rule HIV out completely.
Three things make the biggest difference. The first is timing: the sooner the first dose, the better, ideally within 2 hours and never later than 72. The second is taking every dose, and the third is finishing the full course with follow-up testing.
What helps PEP work, and what gets in the way
| Factor | Helps | Gets in the way |
|---|---|---|
| Timing | First dose within hours | Waiting to see if symptoms appear |
| Daily doses | A fixed time and a reminder | Repeated missed or late doses |
| The full course | All 28 days, even if you feel fine | Stopping early because of mild side effects |
| Follow-up | HIV tests after the course | Treating a test on day one as final |
If you’re unsure how much time you have, check the 72-hour PEP window before reading further.
Your 28 days
Guides for every stage of your PEP course.
Once you have started, most questions fall into a few practical areas, and each has its own detailed guide.
- Feeling unwell: PEP side effects and how long they last explains what is normal and when to call.
- A late or missed tablet: what to do if you take PEP late covers each scenario, including vomiting.
- Choosing what comes next: PEP vs PrEP explained side by side helps if you are likely to be at risk again.
- Planning the cost: the PEP price in Pattaya and what it includes sets out typical ranges.
If something isn’t covered, a short message is usually quicker than searching. Tell us which day of the course you are on and what is worrying you.
Pattaya, Thailand
Don’t wait until tomorrow.
Worried about a recent exposure? Talk to us now. It’s confidential, and the sooner you start, the better PEP works.