If you missed a PrEP dose, take it as soon as you remember, then carry on at your usual time. Never take two pills to catch up on daily PrEP.
For most people on daily PrEP, one missed pill is not an emergency. What matters is how many doses you missed, the type of sex you had and whether you use daily or on-demand 2-1-1 PrEP.
Quick answer: what to do right now
Find your situation below. If you're unsure, a doctor can help you decide in a short message.
Try not to panic. A missed pill feels big in the moment, but in most cases the fix is simple, and knowing the rules ahead of time makes the next slip much less stressful.
Missed dose scenarios at a glance
| What happened | What to do |
|---|---|
| A few hours late (daily) | Take it now, then carry on as normal |
| Remembered near your next dose (daily) | Skip it, take the next one on time |
| Missed one day (daily) | Restart at your usual time, no double dose |
| Missed several days, no sex | Talk to a doctor before restarting |
| Missed several days, then sex | Ask about PEP within 72 hours |
| Late 2-1-1 dose | Take it as soon as you remember |
Daily PrEP: how late is too late?
Daily PrEP is fairly forgiving once it has built up in your body. The rules are simple, but they differ slightly depending on the type of sex you have.
Missed your dose by a few hours
If you're 6 or even 12 hours late, take the pill as soon as you remember. Then take your next one at the usual time.
You don't need to shift your whole routine. A few hours either way makes little difference once PrEP is established.
Remembered close to your next dose
If it's almost time for your next pill, skip the missed one. Take the next dose at your normal time and carry on.
Taking two pills together won't give you extra protection. It is more likely to upset your stomach.
Missed one whole day
Missing a single day happens to most people at some point. The i-Base guide on missing a PrEP pill says daily users get good protection for anal sex as long as they take at least four pills a week.
For vaginal or front-hole sex, the medicine builds up more slowly in the tissue, so daily pills matter more. If you miss doses often, talk to a doctor about ways to make it easier.
Missed several days of PrEP
If you've missed several days in a row, your protection may have dropped. This is especially true if you are still in your first week or three of PrEP, before it is fully working.
If you haven't had sex since
Don't just restart and hope. Message a doctor first, because you may need an HIV test before you restart, and the lead-in time may begin again.
Our guide to how long PrEP takes to work explains the 7-day and 21-day timelines that apply when you restart.
If you've had sex since
If you had condomless sex while doses were missed, and it was in the last 72 hours, ask about PEP, not PrEP, as soon as possible. PEP is a separate treatment that works best the sooner it is started.
Then speak to your PrEP doctor before restarting. They will usually want an HIV test first.
Missed doses in your first weeks
Missed pills matter more at the start, before PrEP is fully working. If you miss a dose in the first 7 days (anal sex) or 21 days (vaginal or front-hole sex), count your protection date from when you got back on track, and use condoms until then.
Missed a 2-1-1 dose
On-demand PrEP leaves less room for error, because every dose counts. Here's what to do for each one.
- Late with the 24-hour or 48-hour pill: take it as soon as you remember, then continue the schedule.
- Forgot the double dose before sex: contact a doctor the same day; PEP within 72 hours may be the safer option.
- Took one pill instead of two before sex: ask a doctor for advice straight away.
If sex carries on over several days, the same rule applies to each extra daily pill. Take any late pill as soon as you remember, and keep going with one a day until 2 days after the last time you had sex.
Is 2-1-1 still right for you?
If you often find the timing hard, daily PrEP may suit you better. Our guide to on-demand PrEP and the 2-1-1 schedule compares the two.
How to stop missing PrEP doses
Most missed doses come from a change in routine: a late night, a trip, a new job. A few small habits help a lot.
- Tie it to a daily habit, such as brushing your teeth or your first coffee.
- Set a phone alarm with a discreet label.
- Use a weekly pill box, so you can see at a glance if you missed one.
- Keep spare pills in your bag or at a partner's place.
- Add your doses to your calendar with the PrEP planner, which can export reminders.
Side effects making you skip pills?
Some people skip doses because PrEP upsets their stomach in the first weeks. This usually settles, but tell your doctor rather than quietly stopping; taking the pill with food or at a different time of day often helps.
Holidays and late nights
Travel and drinking are the two biggest reasons people forget. Our pages on PrEP and alcohol and taking PrEP on your Thailand trip have tips that help.
Getting PrEP support in Pattaya
If you've missed doses while staying in Pattaya, Jomtien or Naklua, you don't have to sort it out alone. We can arrange an HIV test, help you restart safely and top up your supply; see HIV testing in Pattaya for how testing works.
New to PrEP here? Our guide to getting PrEP in Pattaya explains the first visit and the 3-monthly check-ups.
Missed a pill and not sure what it means for you? Message us on LINE or WhatsApp with what happened, and we'll help you work out the next step.
Frequently asked questions
What happens if you miss a day of PrEP?
For most people established on daily PrEP for anal sex, one missed day doesn't make a big difference. Take your next pill at the usual time and don't double up.
Should I take two PrEP pills if I missed one?
No. On daily PrEP, never take two to catch up. The only time you take two pills at once is the first dose of 2-1-1, or as your doctor advises.
I missed my PrEP dose by 12 hours. Am I still protected?
If you've been taking PrEP regularly, a 12-hour delay is unlikely to matter. Take the pill now and the next one at your usual time.
Can I miss one day of PrEP if I have vaginal sex?
It is best not to. Protection for vaginal or front-hole sex depends more on taking PrEP every day, so speak to a doctor if you miss doses.
Do I need an HIV test after missing PrEP?
If you missed several days, especially with sex in between, yes. A doctor will usually test you before you restart.