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Mefloquine (Lariam®)

Malaria is a serious infectious disease transmitted by mosquitoes. Malaria is found in Iraq, Afghanistan, and many areas in Africa, South America, and Asia.

Mefloquine is a round, white tablet taken once a week that can help prevent malaria for travelers. It is administered to both military personnel, including those serving in Iraq and Afghanistan, and civilians, although it is used less than it has been in the past.

Mefloquine is used based on recommendations from the Centers for Disease Control and Prevention. The brand Lariam® is no longer sold in the United States, although other brands of mefloquine are available. Mefloquine is particularly helpful for those who are unable to take other medications to prevent malaria such as doxycycline and atovaquone-proguanil.

Mefloquine side effects

Hand holding a foil blister pack with small white pills

The most commonly reported side effects from mefloquine are nausea, vomiting, diarrhea, dizziness, difficulty sleeping, and bad dreams. These symptoms are usually mild and may not cause people to stop taking the medicine. However, consult with your prescribing provider if you are concerned. Other side effects include convulsions or seizures, restlessness, confusion, and unusual behavior. People with liver problems, or those who drink alcohol or take medicines that affect the liver, may take longer to eliminate mefloquine from the body.

Recent scientific literature has suggested side effects including mood changes, bad or vivid dreams, agitation, suicidal thoughts, and suicidal behavior. How often these side effects occur is not fully understood. Contact a health care provider as soon as possible if you experience any side effects.

Although it is very effective at preventing malaria, individuals with the following conditions should not take mefloquine:

  • Psychiatric conditions including active depression, a recent history of depression, generalized anxiety disorder, psychosis, schizophrenia, or other major psychiatric disorders. 
  • Seizure disorders (epilepsy)
  • Certain heart conditions (irregular heartbeat and conduction problems)
  • Those taking certain medications, as advised by a health care provider

Mefloquine was approved by the Food and Drug Administration (FDA) in May 1989. In 2013, the FDA published a safety alert on mefloquine and added a black box warning (its strongest warning) to the drug label.  The FDA notice pointed out that neurologic side effects can include dizziness, loss of balance (vestibular problems), or ringing in the ears (tinnitus).   The safety alert also discussed psychiatric side effects which can include feeling anxious, mistrustful (paranoia), depressed, or having hallucinations (seeing or hearing things that are not there).   Neurologic or psychiatric side effects may occur at any time during drug use, and may last for months to years after the drug is stopped. 

If you are thinking about suicide, seek appropriate care immediately. Contact the Veterans Crisis Line at 1-800-273-8255 (press 1) or through online chat.

Recent Research

VA and the Department of Defense published the following research findings:

Schneiderman AI, Cypel YS, Dursa EK, Bossarte R. Associations between use of antimalarial medications and health among U.S. Veterans of the wars in Iraq and Afghanistan. Am J Trop Med Hyg 2018.

Eick-Cost AA, Hu Z, Rohrbeck P, Clark LL. Neuropsychiatric outcomes after mefloquine exposure among U.S. military service members. Am J Trop Med Hyg 2017; 96: 159-166.

Health concerns?

If you are concerned about mefloquine use, or have short or long-term potential side effects from taking mefloquine, talk to your health care provider.

VA offers a variety of health care benefits to eligible Veterans. Not enrolled in the VA health care system? Find out if you qualify for VA health care.

Compensation benefits for health problems

Veterans may file a claim for disability compensation for health problems they believe are related to mefloquine use during military service. VA decides these claims on a case-by-case basis. File a claim online.

Learn more about VA benefits.

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