Many people who start PEP on Koh Samui do not finish it here. Holidays are short, and the 28-day course is long. The good news is that finishing PEP at home is completely normal, and with a little planning, nothing about leaving the island needs to interrupt it.
This guide covers what to sort out before you leave, how to handle flights and time zones, and how to pick up follow-up care at home.
Key points
- Tell the doctor your travel dates at the very first visit.
- Carry PEP in your hand luggage, in its original packaging, with your paperwork.
- Keep doses about 24 hours apart when crossing time zones. Do not double up.
- Plan follow-up HIV tests at about 6 weeks and 3 months, wherever you are.
Before you leave the clinic
The best time to plan for your flight is the first visit. Tell the doctor:
- When you are leaving Samui, and whether you are stopping in Bangkok or elsewhere
- Where you will be for the rest of the 28 days
- Whether you can easily see a doctor or sexual health clinic at home
The doctor can then plan your supply around those dates, and talk you through what to do if anything changes.
Paperwork worth having
Ask for an English medical summary. It should include:
- The date and time of the exposure
- The date you started PEP
- The names and doses of the medicines
- Your baseline test results
- The follow-up test dates the doctor recommends
This helps your doctor at home continue your care, and helps at airports if anyone asks about your medicine. If you are planning an insurance claim, ask for an itemised English receipt as well.
Starting PEP before a flight?Tell us your travel dates in your first message and the doctor will plan your course around them.
Flying with PEP
Carrying a personal supply of prescribed medicine is routine. A few tips:
- Keep it in hand luggage. Checked bags get lost, and you cannot afford a gap.
- Keep it in the original packaging with the pharmacy label if there is one.
- Bring your medical summary in case you are asked.
- Check the rules of your destination if you are going somewhere with strict medicine import rules. Most countries allow a personal supply with documentation.
Time zones: keeping your doses on track
PEP works best with steady levels of medicine in the body, so try to keep doses roughly 24 hours apart. A few practical approaches:
| Situation | What to do |
|---|---|
| Flying west, gaining hours | Take the next dose at your usual Samui time, then shift by an hour or two a day |
| Flying east, losing hours | Take the next dose a little early rather than late, then shift gradually |
| Long-haul overnight flight | Set an alarm on your phone in Samui time for the dose during the flight |
| Missed dose | Take it as soon as you remember, unless the next one is nearly due |
Never take two doses at once to catch up. If you are unsure, message the clinic, even from abroad.
Side effects while travelling
Mild nausea or tiredness can feel worse on a long flight. Take your dose with food, stay hydrated and go easy on alcohol in the airport lounge. Avoid taking antacids or mineral supplements at the same time as your PEP dose, as some can reduce absorption. If you develop a rash, yellowing skin or feel properly unwell, see a doctor wherever you are.
Picking up care at home
Once you are home, contact a sexual health clinic or your own doctor, show them your medical summary and let them know when your course ends. In many countries, sexual health services handle PEP follow-up routinely and can:
- Continue your supply if needed
- Arrange follow-up HIV tests at about 6 weeks and 3 months after the exposure
- Test for other STIs at the right time
- Discuss PrEP if you expect future exposures
Follow-up tests, wherever you are
Follow-up HIV testing is what confirms PEP worked, so do not skip it. Put the dates in your calendar before you fly. If you are travelling for longer, many clinics, pharmacies and self-test kits can cover it. Our guide to when to test for HIV explains the timing.
Still on the island when questions come up
You can message the clinic on WhatsApp throughout the course, wherever you are. Questions about side effects, missed doses or test dates are answered in English by the medical team.
Already home with a question?Message us on WhatsApp. The doctor can help, even after you have left Koh Samui.
Frequently asked questions
Will airport security take my PEP tablets?
Tablets in personal quantities are allowed in hand luggage. Keep them in their packaging with your medical summary.
Can I get the rest of my course from my doctor at home?
Often, yes. Bring your medical summary so they know exactly which medicines you are on. Availability varies by country, so planning your supply before you leave is the safest option.
What if I lose my tablets while travelling?
Contact a doctor or sexual health clinic immediately and show them your paperwork. Do not wait until the next day if you can avoid it.
Do I still need follow-up tests if I feel fine?
Yes. Feeling well does not confirm PEP worked. Only the follow-up tests do.