PEP (Post-Exposure Prophylaxis)
PEP is an emergency treatment that reduces HIV risk after a possible exposure; it should be started within 72 hours and taken for 28 days without interruption.
What is PEP?
PEP is an emergency treatment that reduces the risk of acquiring HIV after a possible exposure to the virus.
The sooner you start it, the more protection you get.
When should it be used?
After a possible exposure to HIV through:
- Sex without a condom or with a condom that broke or slipped.
- Blood exposure (shared injections, accidents, wounds).
- Material contaminated with blood or body fluids.
- Sexual violence.
It must be started as soon as possible and no later than 72 hours (3 days) after exposure.
How does it work?
- HIV may enter the body after exposure.
- PEP uses medicines that stop HIV from multiplying.
- If taken correctly for 28 days, the risk drops a lot.
- It is not 100% effective, so starting early and completing the full course is essential.
PEP does not replace other prevention strategies. Use condoms and test regularly.
Which regimens are available?
| Regimen | Medicines | Use | Duration |
|---|---|---|---|
| Preferred regimen (current) | TDF/FTC (tenofovir disoproxil fumarate / emtricitabine) + Dolutegravir | Adults and adolescents (>= 35 kg). | 28 days without interruption |
| Alternative regimen 1 | TDF/FTC + Raltegravir | When dolutegravir cannot be used. | 28 days without interruption |
| Alternative regimen 2 | TAF/FTC* + Dolutegravir | For some people (check specific indications). | 28 days without interruption |
*TAF/FTC has not been studied for all PEP situations. Always consult a healthcare professional.
How should it be taken?
- Start fast: ideally within the first 2 hours. Maximum 72 hours (3 days) after exposure.
- Take the full treatment: take all medicines every day, at the same times.
- Duration: PEP must be taken for 28 days in a row, without interruptions.
- Do not skip doses: interruptions may reduce effectiveness.
Always go to a health service for assessment, prescription, and follow-up during treatment.
When should it NOT be used?
- If more than 72 hours have passed since exposure.
- If you already live with HIV.
- If the exposure was only casual contact (kissing, hugging, saliva, sharing dishes, bathrooms).
- In very low-risk exposures (always check with a healthcare professional).
There should always be an individual risk assessment.
Common side effects
- Nausea
- Gastrointestinal discomfort
- Headache
- Tiredness
These are usually mild and temporary. If they are intense or persistent, talk with your healthcare professional.
Recommended follow-up
| Check | Frequency |
|---|---|
| HIV | Baseline test, at 4-6 weeks, and at 3 months |
| Kidney function | Depending on the regimen and health condition |
| STIs | Protection against other sexually transmitted infections |
| Hepatitis B and C | Depending on exposure and background |
| Pregnancy | If pregnancy is possible, let the healthcare team know |
The timing of follow-up may vary depending on the person and the healthcare team’s criteria.
Key self-care messages
- PEP is very effective if it is started on time and taken completely.
- Use alarms or reminders so you do not miss doses.
- If you feel nauseous, take it with food or ask for guidance.
- Carry your medicine with you wherever you go.
- Talk to someone you trust or ask for support if you need it.
PEP protects against HIV, but not against other STIs. Use condoms and test regularly.
Missed a dose?
- If it has been LESS THAN 12 HOURS since the usual time: take it as soon as you remember and continue on your normal schedule.
- If it has been MORE THAN 12 HOURS: take it as soon as you remember and continue with the next dose at the usual time. Do not double the dose and do not stop treatment.
If you have any questions, contact the health service.
This information is educational and does not replace medical advice. Every body is different and recommendations may vary. Always consult a healthcare professional for personalised guidance.