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Mefloquine (By mouth)

Mefloquine (ME-floe-kwin)

Prevents and treats malaria.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

Do not use this medicine if you have had an allergic reaction to mefloquine or similar medicines (such as quinine or quinidine), or if you have a history of seizures. Do not use this medicine to prevent malaria if you have an emotional or mental disorder, such as anxiety, depression, psychosis, or schizophrenia.

How to Use This Medicine:


  • Your doctor will tell you how much medicine to use. Do not use more than directed.
  • This medicine comes with a Medication Guide and an information wallet card. Read and follow the instructions carefully. Talk with your doctor if you have any questions.
  • Do not take this medicine on an empty stomach. The best time is after your main meal of the day. Drink at least 8 ounces (1 cup) of water with each dose of medicine.
  • You may crush the tablet and mix it with a little water, milk, or other beverage to give the medicine to a young child.
  • Malaria prevention while traveling: You may need to start using this medicine at least 1 week before you start your trip. You may also need to keep using this medicine for 4 weeks after you get home. Ask your doctor about your schedule. Take this medicine on the same day of the week each time.
  • Call your doctor or pharmacist for instructions if vomiting occurs within 1 hour after a dose is taken.
  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Do not take ketoconazole (Nizoral®) or halofantrine (Halfan®) with mefloquine or within 15 weeks after the last dose of this medicine, unless your doctor tells you otherwise.
  • Make sure your doctor knows if you are also using rifampin, other medicine for malaria (such as chloroquine, quinidine, quinine), medicine for seizures (such as carbamazepine, phenobarbital, phenytoin, valproic acid), or medicine for heart rhythm problems (such as amiodarone, disopyramide, dofetilide, sotalol).
  • If you need typhoid vaccine, you may need to finish it at least 3 days before you start taking mefloquine for malaria prevention.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have liver disease, epilepsy or seizures, or a history of depression or other psychiatric problems. Make sure your doctor knows if you have heart disease, heart block, or heart rhythm problems (such as prolonged QT interval).
  • Use birth control while you are taking this medicine and for 3 months after you stop. If you think you have become pregnant while using this medicine, tell your doctor right away.
  • This medicine may cause the following problems:
    • Psychiatric problems (could be long-term, and may include anxiety, paranoid thoughts, depression, hallucinations, or thoughts of suicide)
    • Nervous system problems (could be long-term or permanent, and may include dizziness or balance problems)
  • You could still get malaria even while using this medicine. If you get sick or have a fever, call your doctor.
  • This medicine may make you dizzy or drowsy. Do not drive, use machines, or do anything else that could be dangerous until you know how this medicine affects you.
  • You will need to have your eyes and liver checked if you take this medicine for longer than 1 year.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Dark-colored urine or pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, yellow skin or eyes
  • Faintness, dizziness, lightheadedness, balance problems, ringing in your ears
  • Fast, slow, pounding, or uneven heartbeat
  • Feeling confused, depressed, nervous, restless, or paranoid
  • Fever, chills, cough, sore throat, and body aches
  • Seeing, hearing, or feeling things that are not there
  • Unusual behavior or thoughts of hurting yourself

If you notice these less serious side effects, talk with your doctor:

  • Diarrhea, vomiting, stomach pain
  • Headache
  • Trouble sleeping

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 1/7/2020

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