Medically reviewed by Drugs.com. Last updated on May 28, 2022.
Mefloquine may cause neuropsychiatric adverse reactions that can persist after mefloquine has been discontinued. Mefloquine should not be prescribed for prophylaxis in patients with major psychiatric disorders. During prophylactic use, if psychiatric or neurologic symptoms occur, the drug should be discontinued and an alternative medication should be substituted
The Lariam brand name has been discontinued in the U.S. If generic versions of this product have been approved by the FDA, there may be generic equivalents available.
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Antimalarial
Uses for Lariam
Mefloquine is used to treat malaria. It is also used to prevent malaria infection in areas or regions where it is known that other medicines (eg, chloroquine) may not work.
Mefloquine belongs to a group of medicines known as antimalarials. It works by preventing or treating malaria, a red blood cell infection transmitted by the bite of a mosquito.
Malaria transmission occurs in large areas of Central and South America, Hispaniola, sub-Saharan Africa, the Indian subcontinent, Southeast Asia, the Middle East, and Oceania. Country-specific information on malaria can be obtained from the Centers for Disease Control and Prevention (CDC), or from the CDC's web site at http://www.cdc.gov/travel.
This medicine is available only with your doctor's prescription.
Before using Lariam
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of mefloquine in children. However, safety and efficacy have not been established in children younger than 6 months of age.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of mefloquine in the elderly. However, elderly patients are more likely to have age-related heart problems, which may require caution in patients receiving mefloquine.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Aripiprazole Lauroxil
- Arsenic Trioxide
- Chloral Hydrate
- Inotuzumab Ozogamicin
- Sodium Phosphate
- Sodium Phosphate, Dibasic
- Sodium Phosphate, Monobasic
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Valproic Acid
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Blood or bone marrow problems (eg, agranulocytosis, aplastic anemia) or
- Bradycardia (slow heartbeat), severe or
- Heart block, severe or
- Heart disease, severe or
- Heart rhythm problems (eg, arrhythmia, prolonged QT interval), history of—Use with caution. May make these conditions worse.
- Depression, active or history of or
- Generalized anxiety disorder, history of or
- Psychosis (mental illness), history of or
- Schizophrenia (mental illness), history of or
- Seizures, history of—Should not be used in patients with these conditions.
- Epilepsy—May increase risk of having convulsions.
- Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
- Malaria, severe or life-threatening—Your doctor may want you to receive an antimalarial injection before taking this medicine.
Proper use of Lariam
Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
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.
Mefloquine is best taken with a full glass (8 ounces) of water and with food, unless otherwise directed by your doctor.
Mefloquine may be crushed and put in water, milk, or juice to make it easier to take.
For patients taking mefloquine to prevent the symptoms of malaria:
- Your doctor will want you to start taking this medicine one week before you travel to an area where there is a chance of getting malaria.
- Also, you should keep taking this medicine while you are in the area where malaria is present and for 4 weeks after you leave the area. No medicine will protect you completely from malaria. However, to protect you as completely as possible, it is important that you keep taking this medicine for the full time your doctor ordered. Also, if fever or “flu-like” symptoms develop during your travels or within 2 to 3 months after you leave the area, check with your doctor immediately.
- This medicine works best when you take it on a regular schedule. For example, if you are to take it once a week, it is best to take it on the same day each week. Do not miss any doses. If you have any questions about this, check with your doctor.
Keep using this medicine for the full treatment time, even if you feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.
Children may vomit after taking this medicine. Your child may vomit some of the dose of medicine. Contact your child's doctor if vomiting occurs. The doctor may need for you to give your child more medicine.
The number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on whether you are using mefloquine to prevent or to treat malaria.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For treatment of malaria:
- Adults—1250 milligrams (mg) or five tablets as a single dose.
- Children 6 months of age and older—Dose is based on body weight and must be determined by your doctor. The usual dose is 20 to 25 mg per kg of body weight as a single dose or two doses (divide the single dose by two) taken 6 to 8 hours apart. Taking two doses may decrease the occurrence of unwanted side effects.
- Children younger than 6 months of age—Use and dose must be determined by your doctor.
- For prevention of malaria:
- Adults and children weighing over 45 kilograms (kg)—250 milligrams (mg) (1 tablet) 1 week before traveling to an area where malaria occurs. Then, 250 mg once a week on the same day of each week and preferably after your main meal while staying in the area and every week for 4 weeks after leaving the area.
- Children 6 months of age and older—Dose is based on body weight and must be determined by your doctor.
- Children weighing 30 to 45 kg: 187.5 mg (¾ tablet) 1 week before traveling to an area where malaria occurs. Then, 187.5 mg once a week while staying in the area and every week for 4 weeks after leaving the area.
- Children weighing 20 to 30 kg: 125 mg (½ tablet) 1 week before traveling to an area where malaria occurs. Then, 125 mg once a week while staying in the area and every week for 4 weeks after leaving the area.
- Children weighing 10 to 19 kg: 62.5 mg (¼ tablet) 1 week before traveling to an area where malaria occurs. Then, 62.5 mg once a week while staying in the area where malaria occurs and every week for 4 weeks after leaving the area.
- Children weighing 5 to 9 kg: 5 mg per kg of body weight 1 week before traveling to an area where malaria occurs.
- Children younger than 6 months of age and weighing less than 5 kg—Use and dose must be determined by your doctor.
- For treatment of malaria:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions while using Lariam
It is important that your doctor check your or your child's progress after treatment. This is to make sure that the infection is cleared up completely, and to allow your doctor to check for any unwanted effects. Blood tests may be needed to check for unwanted effects.
If your or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.
Do not take halofantrine (Halfan®) or ketoconazole (Nizoral®) with mefloquine or within 15 weeks after the last dose of this medicine. This may increase the risk for more serious problems.
Contact your doctor right away if you or your child have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.
Tell your doctor right away if you or your child are feeling anxious, confused, depressed, restless, or having unusual thoughts or behavior after using mefloquine.
Check with your doctor right away if you have the following symptoms after taking this medicine: dizziness, feeling of constant movement of self or surroundings, seizures, or trouble sleeping. These symptoms may continue to occur for months or years after stopping treatment with mefloquine.
Check with your doctor right away if you or your child have flu-like symptoms (such as chills, fever, headache, or muscle pains) again after treatment with this medicine.
Use birth control pills while you are taking this medicine and for 3 months after stopping it. If you think you have become pregnant while using this medicine, tell your doctor right away.
This medicine may cause serious allergic reactions. Call your doctor right away if you or your child have a rash, itching, hives, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.
Mefloquine may cause vision problems. It may also cause some people to become dizzy or lightheaded, lose your balance, or to have hallucinations (seeing, hearing, or feeling things that are not there). Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert or able to see well. This is especially important for people whose jobs require fine coordination. If these reactions are especially bothersome, check with your doctor.
Check with your doctor immediately if blurred vision, difficulty with reading, or any other change in vision occurs during or after treatment. Your doctor may want your eyes be checked by an ophthalmologist (eye doctor).
While you are being treated with mefloquine, do not have any immunizations (vaccinations) without your doctor's approval. Live virus vaccines should be completed 3 days before the first dose of this medicine.
Malaria is spread by the bites of certain kinds of infected female mosquitoes. If you are living in or will be traveling to an area where there is a chance of getting malaria, the following mosquito-control measures will help to prevent infection:
- If possible, avoid going out between dusk and dawn because it is at these times that mosquitoes most commonly bite.
- Wear long-sleeved shirts or blouses and long trousers to protect your arms and legs, especially from dusk through dawn when mosquitoes are out.
- Apply insect repellant, preferably one containing DEET, to uncovered areas of the skin from dusk through dawn when mosquitoes are out.
- If possible, sleep in a screened or air-conditioned room or under mosquito netting sprayed with insecticide to avoid being bitten by malaria-carrying mosquitoes.
- Use mosquito coils or sprays to kill mosquitoes in living and sleeping quarters during evening and nighttime hours.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Lariam side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Aching joints and muscles
- blistering, loosening, peeling, or redness of the skin
- chest pain or discomfort
- convulsions (seizures)
- cough or hoarseness
- hallucinations (seeing, hearing, or feeling things that are not there)
- irregular, pounding, slow, or fast heartbeat or pulse
- lower back or side pain
- mental depression
- painful or difficult urination
- pinpoint red spots on the skin
- red or irritated eye
- sore throat
- sores, ulcers, or white spots in the mouth or on the lips
- stiff neck
- swelling of the ankles, feet, or lower legs
- unusual bleeding or bruising
- unusual tiredness or weakness
Incidence not known
- Blurred or loss of vision
- continuing ringing or buzzing or other unexplained noise in the ears
- disturbed color perception
- double vision
- feeling of constant movement of self or surroundings
- halos around lights
- hearing loss
- hearing problems
- loss of balance
- loss of bladder control
- muscle spasm or jerking of all extremities
- night blindness
- overbright appearance of lights
- sensation of spinning
- severe or continuing headache
- sudden loss of consciousness
- trouble sleeping
- troubled breathing
- tunnel vision
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- emotional problems
- stomach pain
- Abnormal dreams
- loss of appetite
- skin rash
- Loss of hair
Incidence not known
- Acid or sour stomach
- flushing or redness of the skin
- skin rash with a general disease
- stomach discomfort, upset, or pain
- unusually warm skin
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
More about Lariam (mefloquine)
- Side effects
- Drug interactions
- Dosage information
- During pregnancy or Breastfeeding
- Reviews (15)
- Drug images
- En español
- Drug class: antimalarial quinolines
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.