When you cross time zones, you have two options for your medication: keep taking it on home time, so the gap between doses stays the same, or move to local time, so doses fit your day at the destination. Which is right depends on your medication and the length of the trip. Ask your pharmacist before you go, then set your reminders to match the plan.
Our travel checklist covers packing and supply. This guide is only about the clock: what happens to your medication times when you fly, and how to keep reminders accurate across the trip.
Why time zones matter for medication
Your phone changes its clock when you land. A reminder set for 8:00 am moves to 8:00 am local time. If you fly eight hours east, that reminder now fires eight hours earlier in "body time" than it did at home. For some medication that is fine. For others, the gap between doses matters more.
Medication where timing is often more important includes things taken several times a day at fixed gaps, things where a consistent daily time is part of how they work and things that affect sleep or alertness. Your pharmacist can tell you which category yours falls into.
Option one: stay on home time
You keep taking every dose at the same moment it would be at home, whatever the local clock says.
Good for: short trips, small time differences and medication where the gap between doses matters.
The catch: home time can land in the middle of the night at your destination. A 9 pm dose at home in Sydney is 10 am in London during the northern winter, which is easy. A 9 am dose at home is 10 pm in London, which may also suit. Fly the other way and a dose can fall at 3 am.
To stay on home time, your reminders need to stay on home time too. If your app simply follows the phone's clock, every reminder will move when you land.
Option two: move to local time
You switch to taking doses at the same clock time as at home, but in the local time zone.
Good for: longer stays, medication where the time of day matters more than the exact gap, and doses linked to meals or sleep.
The catch: on the travel day the gap between two doses will be longer or shorter than usual. For a big time difference, a pharmacist may suggest moving in steps over a few days rather than all at once.
Planning the travel day
The travel day is where the mistakes happen. Before you fly:
- Write down your home dose times.
- Work out what they are at your destination. Our time zone dose planner does this for you.
- Mark which doses fall during the flight. Keep those doses in your hand luggage.
- Ask your pharmacist how to bridge the gap, if you are switching to local time. Bring the list of times.
- Decide what you will do on the way home. The same change happens in reverse.
On the plane, the cabin crew will often announce the local time at the destination. Ignore it for medication on home time; your plan is what counts.
Daylight saving at either end
If the clocks change at home or at your destination while you are away, the difference shifts by an hour. Around late March to early April and late September to early November, the gap between Australia and Europe or North America changes more than once within a few weeks. Check the difference for your actual travel dates. Our daylight saving guide explains what happens to reminders when clocks change.
Keeping reminders accurate
- Check your phone's time zone setting. Settings > General > Date & Time. With Set Automatically on, the phone changes zone when you land.
- Know what your app does when the zone changes. Some follow local time, some can hold home time.
- Check the first reminder after landing. Make sure it arrives when your plan says it should.
- Log every dose. If something goes wrong mid-trip, a log with real times lets you and your pharmacist work out where you are.
How Cadence handles time zones
Cadence follows your phone's local time by default. Its Travel setting lets you choose a Home time zone and keep your doses on it while you are away, so reminders fire at the same moment they would at home and the gap between doses stays the same. Home time still follows daylight saving at home. When you get back, turn Travel off and everything returns to local time. Each dose is logged with the real time you took it.
If your medication is time-critical, ask your doctor or pharmacist how to handle a long trip before you travel. Cadence will follow whichever plan you choose; it does not choose one for you.
Frequently asked questions
Should I stay on home time or switch?
It depends on the medication and the trip. Ask your pharmacist. Many people stay on home time for short trips and switch for long stays.
What about doses during a long flight?
Plan them before you fly and keep that medication in your hand luggage. Set reminders on the time zone you have chosen, not the cabin clock.
Will my reminders change by themselves when I land?
If your app follows local time, yes. If you have set it to hold home time, no.
Does this apply to a 21/7 pill?
Yes. Ask your pharmacist how to keep a consistent time across the trip, as some pills have a narrower window.
Cadence is a free medication reminder app for iPhone and Apple Watch. It is not medical software and does not give medical advice. Cadence Pro is a one-time purchase, with no subscription.
