Altitude Sickness · Acetazolamide timing
Start Diamox (acetazolamide) about one day (24 hours) before you begin your ascent, and continue it for the first 2 days at altitude (longer if you keep climbing higher). Starting it the day before gives it time to help your body acclimatize as you go up.
| Stage | What to do |
|---|---|
| 1 day before ascent | Start acetazolamide |
| During ascent | Keep taking it as you go up |
| First 2 days at altitude | Continue until you have acclimatized |
| Still climbing higher? | Continue until you reach your highest sleeping elevation and have stayed a couple of days |
| Heading back down | You can stop once you are acclimatized or descending |
The exact dose and schedule are set during your visit, but the pattern is the same: begin the day before, cover the climb, and continue through the first couple of days at your target height.
It still works. Acetazolamide does not only prevent altitude sickness, it also treats it once it has started, so if you forgot to begin the day before, start as soon as you can. Beginning late is far better than not at all. This is also why it is worth carrying a supply rather than hoping to find it at your destination.
Because you start it the day before you ascend, request acetazolamide online a few days before your trip so the prescription is filled and packed.
A $45 asynchronous visit (no video, no membership) for adults in eligible states, reviewed by a licensed nurse practitioner. Tell us your destination and how fast you ascend, and we tailor the timing to your trip.
Start acetazolamide (Diamox) about one day (24 hours) before you begin your ascent to altitude. Starting it the day before gives it time to help your body acclimatize as you go up.
Continue Diamox for the first 2 days after reaching your target altitude, or until you have acclimatized. If you keep ascending to higher sleeping elevations, continue it until you reach your highest point and have stayed there a couple of days, then you can stop.
It still helps. If you did not start it the day before, begin as soon as you can. Acetazolamide also treats altitude sickness that has already started, not just prevents it, so starting late is better than not at all. Request the prescription a few days before travel so you have it in hand.
Yes. Bidwell Health offers a $45 asynchronous online visit, no video and no subscription, for adults in eligible states. A licensed nurse practitioner reviews your trip and sends acetazolamide to your pharmacy when clinically appropriate, so you can start it the day before you ascend.