If you’re planning a trip to a malaria‑risk country, you’ve probably heard the name mefloquine. It’s one of the few pills you can take once a week to keep malaria at bay. This guide breaks down what the drug does, how to take it safely, and what to watch out for, so you can travel with confidence.
Mefloquine belongs to a class called quinoline‑methanols. It slips into the malaria parasite’s cells and blocks a protein the bug needs to survive. The result? The parasite can’t multiply, and your body clears it before it causes symptoms. Because it stays in your bloodstream for several days, a single dose can protect you for a whole week.
When you start a travel regimen, you’ll take a loading dose—usually one tablet a day for three days—followed by a weekly dose for the duration of your stay. The drug’s long half‑life means you don’t have to remember a daily pill, but it also means side effects can linger, so it’s worth knowing the common complaints.
The standard adult dose is 250 mg per tablet. For most travelers, the schedule looks like this: day ‑1, day 0, and day +1 (the loading phase), then a single tablet every 7 days. Start the loading phase at least two weeks before you leave, so any side effects show up while you’re still at home.
Typical side effects are mild—headache, nausea, or a brief feeling of dizziness. About 5‑10 % of users report vivid dreams or mood changes. If you notice severe anxiety, depression, or hallucinations, stop the drug and call a doctor right away. People with a history of seizures, certain heart rhythm problems, or severe psychiatric disorders should avoid mefloquine unless a doctor says it’s safe.
Alcohol can worsen nausea, and some foods (especially grapefruit juice) may interfere with how the body processes the drug. Keep a list of any other medicines you take, because mefloquine can interact with antacids, some antidepressants, and certain HIV meds.
If you miss a weekly dose, take it as soon as you remember—unless it’s less than eight hours before your next scheduled dose. In that case, skip the missed one and continue with the regular schedule. Don’t double up; doing so raises the risk of side‑effects.
Pregnant women should only use mefloquine if the benefits outweigh the risks, and it’s not a first‑choice drug for infants under five years old. Kids need a weight‑based dose, which a doctor can calculate.
When you return home, keep the pills for a few weeks in case you need a rescue dose after exposure. Store them in a cool, dry place away from direct sunlight.
Bottom line: mefloquine is a convenient option for long trips to malaria zones, but it requires a short lead‑in period and a watchful eye on side effects. Talk to your healthcare provider, follow the dosing schedule, and you’ll have one less worry on your travel checklist.
