Mefloquine in the News: Recent Developments and Research Breakthroughs

For decades, mefloquine was one of the go-to pills for travelers heading to malaria-prone regions. You’d pick it up at the travel clinic, take it once a week, and feel confident you were protected. But in recent years, the story around mefloquine has changed - and not for the better. Recent studies, government warnings, and patient reports have pushed it from a trusted preventive to a controversial option. What’s really going on with mefloquine in 2025?

Why Mefloquine Is Back in the Spotlight

Mefloquine, sold under the brand name Lariam, was introduced in the 1980s as a long-acting antimalarial. It worked well against Plasmodium falciparum, the deadliest malaria parasite, and its weekly dosing made it convenient. But over time, reports piled up: people taking mefloquine experienced nightmares, anxiety, dizziness, and even suicidal thoughts. The U.S. FDA added a black box warning in 2013 - the strongest possible - for psychiatric and neurological side effects.

Now, new data from the World Health Organization’s 2024 Global Malaria Report shows mefloquine use has dropped by 62% in high-income countries since 2018. Why? Because better alternatives have emerged. Atovaquone-proguanil (Malarone) and doxycycline are now preferred for most travelers. They’re just as effective, have fewer serious side effects, and are easier to tolerate.

But mefloquine hasn’t disappeared. It’s still used in parts of Southeast Asia and sub-Saharan Africa where drug resistance patterns make other options less reliable. And here’s the twist: recent clinical trials suggest it might still have a role - but only under strict supervision.

The 2025 Research Breakthrough: Mefloquine and Drug Resistance

In May 2025, researchers at the Mahidol-Oxford Research Unit in Thailand published a landmark study in The Lancet Infectious Diseases. They analyzed over 12,000 malaria cases across Cambodia, Laos, and Vietnam. What they found surprised even seasoned experts: mefloquine-resistant strains of P. falciparum were declining in areas where the drug had been used heavily for years.

The reason? Resistance to mefloquine comes with a biological cost. Parasites that mutate to survive mefloquine become slower to reproduce and less fit in the wild. When mefloquine use dropped, these resistant strains couldn’t compete with the more efficient, non-resistant ones. In simple terms, the parasite paid a price for resisting the drug - and it’s now losing the battle.

This isn’t just academic. It means mefloquine could potentially be reintroduced in targeted areas as part of a rotation strategy. Instead of using it continuously, health officials might use it for short bursts every 5-7 years, letting sensitive strains bounce back. Think of it like giving the parasite a break - so the drug can work again.

Neurological Risks: What the Latest Studies Say

Even as resistance declines, the neurological risks remain a major concern. A 2024 meta-analysis of 17 studies involving over 300,000 travelers, led by the University of Oxford, found that mefloquine users were 2.7 times more likely to report severe neuropsychiatric events than those using atovaquone-proguanil. These included panic attacks, hallucinations, and depression severe enough to require hospitalization.

What’s new is the discovery of a genetic link. Researchers identified a variant in the ABCB1 gene - responsible for pumping toxins out of brain cells - that makes some people far more vulnerable. People with two copies of this variant had a 1 in 8 chance of serious side effects when taking mefloquine. That’s not rare. It’s common enough that genetic screening could prevent harm.

Some military health services, including the British Ministry of Defence, now offer optional genetic testing before prescribing mefloquine to personnel deploying to high-risk zones. It’s not routine yet, but it’s becoming a standard in specialized clinics.

Who Still Gets Mefloquine Today?

If mefloquine is so risky, why is it still prescribed at all?

• Travelers to remote areas where pharmacies are scarce and daily pills aren’t practical - mefloquine’s weekly dose is a logistical advantage.
• People allergic to other drugs - if you can’t take doxycycline (due to sun sensitivity or stomach issues) or Malarone (due to cost or intolerance), mefloquine may be the only option.
• Cost-sensitive settings - in some low-income countries, mefloquine costs under $0.50 per dose, while Malarone runs over $10 per tablet.

But here’s the catch: doctors now require a full psychiatric screening before prescribing it. You’ll be asked about past anxiety, depression, seizures, or trauma. If you’ve ever had a panic attack, been on antidepressants, or had a head injury - you won’t get it. That’s new. That’s strict. And it’s saving lives.

What This Means for You

If you’re planning a trip to a malaria zone - whether it’s Kenya, Thailand, or Papua New Guinea - here’s what you need to do:

1. Visit a travel clinic at least 6 weeks before departure. Don’t wait until the last minute.
2. Ask about your options: Malarone, doxycycline, and mefloquine. Don’t assume mefloquine is the default.
3. Be honest about your mental health history. Even if you think it’s not relevant - it is.
4. If mefloquine is suggested, ask if genetic testing is available. It’s not offered everywhere yet, but it’s growing.
5. If you’ve taken mefloquine before and felt off - even mildly - tell your doctor. Don’t take it again.

Most travelers today don’t need mefloquine. But for a small group - those with limited options, in hard-to-reach places - it still has value. The key now isn’t whether it works. It’s whether it’s safe for you.

The Bigger Picture: How Malaria Treatment Is Evolving

Mefloquine’s story is part of a larger shift in how we fight malaria. We’re moving away from one-size-fits-all prevention. Now, it’s personalized: based on destination, duration, cost, genetics, and individual health history.

Researchers are also testing new combinations - like putting mefloquine in a slow-release patch or pairing it with a new compound called KAF156. Early trials show promise. The goal isn’t to bring back mefloquine as it was. It’s to use its strengths - long-lasting protection, low cost - while stripping away its dangers.

Meanwhile, vaccines like R21/Matrix-M are rolling out in Africa. They’re not 100% effective, but they’re changing the game. In the next five years, antimalarial pills may become a backup - not the first line of defense.

Final Thoughts: A Drug Reconsidered

Mefloquine isn’t evil. It’s not broken. It’s just a tool that was used too broadly, without enough understanding of who it harmed. Today, we know better. We have better tools. We have better science.

The news isn’t that mefloquine is dead. It’s that we’re learning how to use it wisely. For the right person, in the right place, under the right conditions - it still saves lives. But those conditions are narrower than ever.

If you’re considering mefloquine, don’t just accept it. Ask questions. Demand alternatives. Know your risks. Because in 2025, the safest trip isn’t the one with the cheapest pill - it’s the one with the smartest choice.