Information, not medical advice. This page is general health information to help you find trusted services. It isn't a substitute for advice from a doctor or clinic, and only a clinician can tell you what's right for you. Details and phone numbers can change — check the linked service before relying on them. If you think you need PEP, act now: it only works within 72 hours of exposure. In a medical emergency call 112 (EU) or your local emergency number.
What is PrEP?
PrEP stands for pre-exposure prophylaxis. It's a medicine taken by people who are HIV-negative to stop them getting HIV. When taken as prescribed it is highly effective — close to 100% at preventing HIV from sex. PrEP is usually a single daily tablet (the same drugs used to treat HIV, here used to prevent it), and you stay HIV-negative while taking it correctly.
PrEP is a good option for many people, including gay and bisexual men, trans people, and anyone who feels they may be at higher risk of HIV — for example if you don't always use condoms, have had an STI recently, have used PEP before, or use drugs during sex. You don't have to "qualify" by any single rule: if you think PrEP might be for you, that conversation with a clinic is worth having.
PrEP in Ireland — free through the HSE
In Ireland, PrEP is available free of charge through the HSE's national PrEP programme. You attend an approved PrEP service (public or private) for an assessment and regular check-ups, and the medication is dispensed free through community pharmacies for people who meet the clinical eligibility criteria. The HSE keeps an up-to-date list of approved PrEP providers and how to contact them.
As part of the programme you'll have regular reviews — typically every three months — including HIV and STI testing and kidney-function checks. These appointments are part of what makes PrEP safe and effective, and they're a good chance to look after the rest of your sexual health too.
How to take PrEP — daily or event-based
There are two main ways to take PrEP, and a clinic will help you choose what fits your life:
- Daily PrEP — one tablet every day. This protects against HIV from all types of sex and is suitable for everyone, including trans people and people who have vaginal/frontal sex. It can take up to 7 days of daily dosing to reach full protection (your clinic will advise on timing).
- Event-based PrEP (the "2-1-1" method) — used by some cisgender men who have sex with men when sex is less frequent or planned: 2 tablets 2–24 hours before sex, 1 tablet 24 hours later, and 1 tablet 24 hours after that. Event-based dosing is not recommended for everyone — your clinic will tell you whether it's an option for you.
Whichever method you use, taking PrEP consistently is what makes it work. If you miss doses or want to stop, talk to your clinic so you stay protected.
PrEP prevents HIV — not other STIs. It doesn't protect against chlamydia, gonorrhoea, syphilis or mpox, so regular STI testing (built into the PrEP programme) and other prevention still matter. See our guide on STIs, mpox & vaccinations.
What is PEP — and the 72-hour window
PEP stands for post-exposure prophylaxis. It's an emergency course of anti-HIV medicine taken after a possible exposure to HIV — for example a condom breaking, sex without protection with someone whose status you don't know, or a sexual assault. PEP is a 28-day course, and it must be started as soon as possible and within 72 hours (3 days) of the exposure. The sooner you start, the better it works — every hour counts, so don't wait.
Where to get PEP in Ireland
PEP is free in Ireland and available through public sexual-health, STI and infectious-diseases clinics. If a clinic is closed — in the evening, at the weekend, or on a holiday — and the 72-hour window is running, you can get PEP at a hospital Emergency Department. Sexual Assault Treatment Units (SATUs) also provide PEP if you've experienced a sexual assault.
Acting now? If you may have been exposed to HIV in the last 72 hours, contact a sexual-health clinic or, if none is open, go to a hospital Emergency Department and ask for PEP. Don't delay to "see how you feel" — PEP only works inside the window.
PrEP vs PEP — at a glance
- PrEP is planned, ongoing prevention taken before exposure — daily or event-based — and is close to 100% effective when taken as prescribed.
- PEP is an emergency, one-off 28-day course taken after a possible exposure, started within 72 hours.
- If you find you're using PEP, or thinking about it, that's often a sign PrEP could be a better fit — ask your clinic about starting PrEP afterwards.
PrEP & PEP across the EU
Availability, cost and access routes vary between EU countries, but PrEP and PEP are recognised tools across Europe. PrEPster offers clear, plain-language guides that travel well across borders, and MAN2MAN is a great Ireland-based starting point for gay and bisexual men. If you live outside Ireland, check your national health service or a local sexual-health clinic for how PrEP and PEP are provided where you are.
See also HIV testing & U=U, STIs, mpox & vaccinations, and where to find a sexual-health clinic.
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