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Mefloquine

Warning

Mefloquine may cause mental/mood or nervous system problems. Tell your doctor right away if you have any of these serious side effects, including: mental/mood changes (such as anxiety, depression, restlessness, confusion, hallucinations, suicidal thoughts/attempts), ringing in the ears, dizziness, lightheadedness, loss of balance, or trouble sleeping. These side effects may continue to occur even after stopping mefloquine and certain side effects (such as dizziness, ringing in the ears, loss of balance) may become permanent. This medication should not be used to prevent malaria in people who have mental/mood disorders (such as depression, schizophrenia).

Precautions

Before taking mefloquine, tell your doctor or pharmacist if you are allergic to it; or to quinine or quinidine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: mental/mood disorders (such as depression, anxiety, schizophrenia), seizures, heart problems, liver disorder.

This drug may make you dizzy or lose your balance. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Mefloquine may cause live bacterial vaccines (such as typhoid vaccine) not to work well. Tell your health care professional that you are using mefloquine before having any immunizations/vaccinations.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breastfeeding.

Side Effects

See also Warning section.

Stomach upset/pain, loss of appetite, nausea/vomiting, headache, muscle pain, or diarrhea may occur. If any of these effects last or get worse, tell your doctor promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: loss of coordination, numbness/tingling/pain of hands or feet, vision changes, unusual tiredness, signs of liver disease (such as nausea/vomiting that doesn't stop, dark urine, yellowing eyes/skin).

Get medical help right away if you have any very serious side effects, including: fast/slow/irregular heartbeat, fainting, seizures.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

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Drug information is selected from data included with permission and copyrighted by First DataBank, Inc. This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your healthcare professional. Always seek the advice of your healthcare professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your healthcare professional. This information does not contain any assurances that this product is safe, effective or appropriate for you.

This information is intended only for residents of the United States. Products sold under the same brand names in other countries may contain different ingredients.

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Information expires December 2025.