SIDE EFFECTS: This medication may cause stomach upset, stomach pain, nausea, vomiting, diarrhea, fever, hair loss, ringing in the ears, dizziness, "feeling of spinning", loss of balance, drowsiness, headache, insomnia, strange dreams, or lightheadedness. These effects should subside as your body adjusts to the medication. If these symptoms persist or become severe, contact your doctor or pharmacist promptly.

Dizziness and loss of balance may rarely occur after stopping mefloquine. Tell your doctor if these side effects persist.

Remember that your doctor has prescribed this medication because he or she 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 immediately if any of these unlikely but serious side effects occur: fast, slow, or irregular heartbeat, seizures, muscle pain, loss of coordination, numbness and tingling of hands or feet, vision changes.

If any of the following highly unlikely, but serious side effects occur; call your doctor immediately; you may need to stop using mefloquine and start another medication for malaria prevention: unexplained anxiety, mood changes, depression (sometimes severe, including rare thoughts of suicide), hallucinations, restlessness, confusion.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: 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.

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

Read the Lariam (mefloquine) Side Effects Center for a complete guide to possible side effects »

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.

This medication should not be used if you have the following medical conditions: active or recent depression, anxiety disorder, psychiatric disorders, seizure disorders.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart problems, liver problems.

This medication may cause dizziness or loss of balance. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely.

Use with caution in children.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breast-feeding.