Examples

How It Works

Mefloquine prevents the development of malaria parasites in the blood. Mefloquine does not destroy the Plasmodium (P.) vivax or P. ovale parasites that may remain in the liver.

You take mefloquine as a tablet (orally).

To prevent malaria, you take mefloquine once, 1 to 2 weeks before you travel to an area where malaria is present, and then weekly while you are in the area, and weekly for 4 weeks after you leave.

Mefloquine is used usually to prevent malaria. If used to treat malaria, you may take 2 doses of mefloquine 6 to 12 hours apart.

Why It Is Used

People take mefloquine to prevent malaria and, in rare cases, to treat malaria. It is used to prevent malaria in areas where the strain of P. falciparum is resistant to chloroquine and in Southeast Asia, the Amazon region of South America, and sub-Saharan Africa.

Do not take mefloquine if you have a history of irregular heartbeats (ventricular arrhythmias), abnormal sensitivity to this medicine, psychological conditions (such as depression), or seizures.

How Well It Works

One review of several different studies found that mefloquine is effective in preventing malaria.¹

Medication therapy to prevent malaria is most effective if you take the correct dosage regularly. It's easier to remember if you take your weekly dosage with meals on the same day of the week each week, such as every Monday at lunch.

Medicine to prevent malaria destroys the malaria parasite once the parasite enters the bloodstream. Due to the long life cycle of the parasite, you need to take the medicine for 4 weeks after you leave the area where malaria is present.

Mefloquine is usually effective against all five species of Plasmodium and in regions where the chloroquine-resistant P. falciparum parasite is common.

Side Effects

You may avoid the common side effects of mefloquine by taking the medicine with meals. Common side effects of mefloquine may include:

• Nausea.
• Diarrhea.
• Dizziness.
• Sleep disturbances (such as vivid dreams).
• Headache.
• Seizures.
• Disruption of vision (this is rare).

In rare cases mefloquine causes more serious side effects, such as depression, anxiety, paranoia, hallucinations, confusion, and psychotic behavior. Mefloquine has also been linked with tremor, mood changes, and panic attacks. If you have a history of depression or other psychological conditions, mefloquine may not be right for you. If you take mefloquine and develop anxiety, depression, restlessness, or confusion, contact your doctor immediately, because you may need to stop taking mefloquine and try a different medicine.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

• If you have a history of psychological conditions such as depression, mefloquine may not be right for you.
• The U.S. Food and Drug Administration (FDA) has not approved mefloquine for children. Information on its use in children who weigh less than 65 lb (30 kg) is limited, but the medicine appears to be safe.
• Mefloquine appears to be safe for pregnant women. Talk to your doctor about taking this medicine if you cannot postpone travel until after the baby is born.
• In North America, people generally only use mefloquine to prevent malaria infection from chloroquine-resistant P. falciparum. When taking mefloquine to treat malaria infection, you need higher doses, and central nervous system side effects are common.
• Some species of Plasmodium in Thailand, along the border areas with Cambodia and Myanmar (Burma), are resistant to mefloquine.
• In some areas where malaria is common, travelers may also be advised to get a rabies vaccine if they are staying longer than 30 days, or if their professions expose them to special risks, such as those seen by biologists and veterinarians. If you are taking mefloquine, make sure the rabies vaccine is injected into your muscle (intramuscular). Mefloquine can lessen the effectiveness of this vaccine when it's injected into the skin (intradermal).

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References

Citations

1. Croft AM (2007). Malaria: Prevention in travellers, search date February 2007. Online version of BMJ Clinical Evidence. Available online: http://www.clinicalevidence.com.