Mefloquine (Oral)

As an antimalarial, Mefloquine can be prescribed to patients who have either contracted malaria or who are going to an area that is of high-risk of catching malaria.


Mefloquine is a drug given to patients who have contracted malaria. It is also given to help prevent patients from being infected with malaria if they are going to high-risk regions where other medicines (such as chloroquine) may not be able to work.

This drug belongs to a group of medicines called antimalarials. All such drugs are equipped to help prevent someone contacting the malaria virus or to help treat it. Malaria itself if a red blood cell infection that is transmitted after someone has been bitten by a mosquito.

The threat of malaria transmissions exists in the following places:

  • The Middle East

You can find more country-specific information on malaria from the CDC's (Center for Disease Control and Prevention) website. This is:

Be aware that you can only obtain this medicine with a prescription from your doctor. There are many antimalarials available and your doctor will need to first assess your needs to decide which is most suitable.

Condition(s) treated

  • Malaria

Type of medicine

  • Oral

Side effects

As well as having its intended effects, it is possible that Mefloquine will cause some patients to experience unwanted side effects, Below is a list of the more severe ones. If you experience any of the following, inform your doctor immediately.


  • Hallucinations (feeling, seeing, or hearing, things that are not there)

Incidence not known

  • Troubled breathing

Instead of these more serious ones, you may experience some of the less severe side effects listed below. If you do experience any of these after taking Mefloquine, then you may find they pass over time as your body adjusts to the medicine. However, if you have any of the following and find them bothering or lingering, then tell your doctor.

More common

  • Stomach pain

Less common


  • Loss of hair

Incidence not known

  • Belching

You may experience other side effects not listed here. If this is the case, you can discuss them with your doctor.


Below you can find the typical doses of Mefloquine that are prescribed to patients to either help treat or prevent malaria. Be aware that the exact doses you have been prescribed by your doctor may differ from what is below. This is because every patient's condition is assessed individually to find the most sensible and suitable dose of Mefloquine necessary. You should never take this medicine more often or take more of it unless you have been instructed to do so by your doctor.

For patients treating malaria:

  • Adults. Take 1250 mg (5 tablets) in one single dose.

For patients looking to prevent malaria:

  • Adults and children who weigh above 45kg. Take 250 mg (1 tablet) one week prior to you visiting the at-risk malaria zone. Afterwards, take 250mg (1 tablet) one time each week on the same day. Ideally, this should be after you eat your main meal. After you leave this area, you should continue to take Mefloquine each week for 4 weeks.

You should never miss a scheduled dose of this medicine as doing so will place your health at risk. If you do miss a dose for whatever reason, you should take it as soon as you remember. However, if it is then almost time for your next scheduled dose, you should simply skip the missed one and return to dosing as usual. This is because it is important you do not double dose.

You should take Mefloquine in exactly the manner your doctor prescribes it to you. Do not take it more frequently and do not take any more than required. Once your treatment is over, you should stop taking it.

It comes with a Medication Guide which you should read fully. If you have any questions after doing so, then you should discuss these with your doctor.

You should take Mefloquine with an 8-ounce glass of water and food. This is, of course, as long as you have not been told otherwise by your doctor.

To help make it easier to take, you can crush your tablets and place then in juice, milk, or water.

If you are taking Mefloquine to help prevent symptoms of malaria, here is some extra advice:

  • You will need to start taking this medicine one week prior to you arriving at the at-risk malaria zone.

You should keep taking the medicine for the full term of your treatment. This is even if you start to feel better after just a few doses. By stopping taking this drug too soon, your malaria may not clear up completely.

After taking this medicine, some children may vomit. This includes vomiting up some of the medicine itself. If vomiting does happen to your child then you should tell your doctor. They may require you to give more of this drug to your child.

Be aware that the exact nature of your prescription of Mefloquine will differ depending on whether you are using this drug to prevent or treat malaria. This includes the time you leave between doses, how long you take it for, and how many doses you need each day.


It is possible that other drugs you are currently taking will interact with Mefloquine. You will, therefore, need to inform your doctor of any other drugs you take. That way, they can best anticipate and interactions and take necessary steps. This may require changing one or both of the interacting drugs, or simply altering their doses. Below is a list of drugs with which it is not recommended you take Mefloquine at the same time as.

  • Piperaquine

It is usually not recommended that you take Mefloquine at the same time as any of the following. However, in some circumstances, it may be best for your treatment to take both. If this is the case, then your doctor may wish to alter one or both doses of the medicines.

  • Efavirenz

If you take any of the following drugs at the same time as Mefloquine, then you may be at an increased risk of experiencing certain side effects. However, once again it may be best for your treatment to take both. As such, your doctor may need to alter their doses in some way.

  • Rifampin

It is possible that Mefloquine will interact with certain parts of your dietary intake. Your doctor may need to make changes to certain things you eat, drink, or smoke. For example, you may need to start smoking less tobacco or drinking less alcohol to avoid such unwanted interactions.

Finally, if you have any other medical problems, then you should inform your doctor of these. It is possible they may interact with Mefloquine. In particular point out any of the following if they apply.

  • Severe or life-threatening malaria. Before you take this medicine, your doctor may need you to receive an antimalarial injection


Before being able to prescribe you with this drug, your doctor will first need to assess the extent of your medical condition to see whether or not it is suitable. As a part of this, you will need to tell them about any allergies you have to animals, foods, dyes, or preservatives.

As of writing, there is no efficacy and safety that have been established for the use of this drug in children aged younger than 6 months old. However, the studies that have taken place on older children have not highlighted any pediatric-specific problems that would make this dug less useful.

Similarly, the studies on older patients have not highlighted any geriatric-specific problems that would make this medicine less useful for elderly patients. Do be aware though that older patients are more likely to suffer from age-related heart problems. If this is the case, then more caution will need to be exercised when prescribing this drug.

As of writing, it appears that some studies may have taken place in either pregnant women or adults, but it is unclear as to which and whether any risks were highlighted. Your doctor is best placed to advise you whether it is safe to take Mefloquine whilst pregnant.

As of writing, there are no suitable studies on breastfeeding women using Mefloquine. Your doctor is best placed to advise of any risks of taking this drug whilst breastfeeding. You can then weight and such risks against the benefits of using it.

After treatment, it is important that your doctor is allowed to check your progress. This will help them see if your infection has cleared up completely and to see if there have been ay unwanted effects. To check for such effects, you may need to perform blood tests.

If within a few days of taking this drug, your symptoms do not improve or if they become worse, you should tell your doctor.

You should not take either ketoconazole (Nizoral®) or halofantrine (Halfan®) at the same time as Mefloquine or within 15 weeks of your last dose of it, as doing so may increase your risk of having serious problems.

If you experience any heart rhythm changes after using this medicine, you should tell your doctor immediately. This includes things like a pounding, uneven, or fast heartbeat or feeling faint or dizzy. If you or anyone in your family has ever suffered from problems with their heart rhythm, such as QT prolongation, you should tell your doctor.

If you have any unusual thoughts, feel restless, confused, anxious, or depressed after taking this medicine, tell your doctor.

If you have any of the following symptoms after you have taken Mefloquine, tell your doctor. They could occur for months or even years after you stop using it.

  • Trouble sleeping

If you experience any flu-like symptoms after treatment, then tell your doctor.

Whilst taking Mefloquine and for 3 months after stopping taking it, you should use effective means of birth control. Tell your doctor immediately if you think you have become pregnant in this period.

You may experience a serious allergic reaction after taking this drug. If you experience any of the following symptoms, tell your doctor.

  • Itching

This drug can cause changes to a patient's vision. It can also cause some to become lightheaded or dizzy, to lose their balance, or to experience hallucinations. Therefore, before you drive or perform any dangerous tasks, you should be fully aware of how this drug affects you. If your job required fine coordination, then this is even more important. Check with your doctor if you experience these effects and find them particularly bothersome.

If you have any vision changes or difficulty reading after you take Mefloquine, then tell your doctor. They may need you to be seen by an ophthalmologist.

You should not have any immunizations (vaccines) whilst being treated with this drug unless they have first been approved by your doctor. You should have any live virus vaccines completed at least 2 days prior to your first dose of Mefloquine.

It is from the bites of particular female mosquitoes that you can contract malaria. You should take the following mosquito prevention measure if you are traveling to or living in a malaria zone.

  • Where possible, avoid being outside between dusk and dawn as this is the time that mosquitoes most commonly bite.

You should not take any other medicines at the same time as Mefloquine unless they have first been approved by your doctor, This includes prescription and nonprescription drugs, as well as any herbal or vitamin supplements.


You should store this medicine in a sealed container and keep it at room temperature. It should be kept safely away from children and should not be exposed to moisture, direct light, or heat. Also, never allow it to freeze. Once you have finished your treatment, or if any medicine goes out of date, dispose of any remaining medicine safely and sensibly. Your doctor or pharmacist can advise you on how to do this.


If you are going to an at-risk malaria zone or if you have already contracted malaria, then you may be prescribed with Mefloquine. It can be a useful antimalarial when given to specific patients, however, it is not suitable for everyone. If you are prescribed this drug, then you should follow any guidance your doctor gives about taking it. This includes following any dietary or lifestyle changes they advise, as well as any extra precautionary measures against malaria that you should take.

Above, you can find details on the side effects this drug may cause. If you do experience any of the more severe ones or are worried about your treatment, you should speak to your doctor. They are best placed to understand your exact circumstances and offer any further medical guidance to assist you.