Travel Medicine · Tool

When to start and stop your malaria pills

By Bidwell Cranage, APRN, FNP-C, Member, International Society of Travel Medicine · Clinically reviewed by Ashley Cranage, APRN, FNP-C · Reviewed June 19, 2026

Malaria pills start before you arrive and continue after you leave, and the after part is where people slip up. Doxycycline continues for 4 weeks after you leave the malaria area; atovaquone-proguanil (Malarone) for only 7 days. Enter your dates below to get the exact start day, last dose, and how many tablets to fill.

The rules behind it

MedicationStartStopDaily dose
Doxycycline (malaria)1 to 2 days before entering the area4 weeks (28 days) after you leave100 mg once a day
Atovaquone-proguanil / Malarone (malaria)1 to 2 days before entering the area7 days after you leaveOne adult tablet (250/100 mg) once a day with food
Acetazolamide / Diamox (altitude)The day before you ascendAfter the first couple of days at altitude, once acclimatized125 mg twice a day

The big takeaway: Malarone has a short 7-day tail, which is why short and last-minute trips often pick it, while doxycycline must continue a full 4 weeks after you leave, a step travelers commonly cut short and a common reason prophylaxis fails. Acetazolamide for altitude is about gradual ascent first; the pill supplements it.

This is general timing, not a prescription. Your exact start and stop depend on your itinerary, layovers, and health, which your clinician confirms. We prescribe doxycycline or Malarone (not mefloquine, primaquine, or tafenoquine, which need extra screening), and pills never replace mosquito-bite avoidance. See how we decide.

FAQ

When should I start taking malaria pills?

Doxycycline and atovaquone-proguanil (Malarone) are both started 1 to 2 days before you enter the malaria area, then taken once a day while you are there. Mefloquine, which we do not prescribe online, has to be started about 2 weeks before travel instead.

How long do I take Malarone after I leave the malaria area?

Atovaquone-proguanil (Malarone) is continued for 7 days after you leave the malaria area. That short tail is why many short-trip and last-minute travelers choose it over doxycycline.

How long do I take doxycycline after travel?

Doxycycline is continued for 4 weeks (28 days) after you leave the malaria area. Stopping early is a common mistake that can leave you unprotected, so plan to fill enough tablets for the full course.

When do I start altitude medicine (acetazolamide/Diamox)?

Acetazolamide is usually started the day before you ascend to high altitude and continued through the first couple of days at altitude, then stopped once you have acclimatized. Gradual ascent is still the most important prevention.

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Related

Reviewed by Bidwell Cranage, APRN, FNP-C, AANP board-certified Family Nurse Practitioner and Member, International Society of Travel Medicine.
Sources: CDC Yellow Book (Malaria); DailyMed doxycycline and atovaquone-proguanil labels; Wilderness Medical Society 2024 altitude guidelines. The calculator is general guidance; confirm timing with your clinician for your exact itinerary.