Mefloquine is the active ingredient in Lariam, a medication used for the prevention of malaria. Mefloquine tablets need to be taken on a weekly basis to prevent infection with the malaria parasite, which is passed on by mosquitoes. Mefloquine is only available on prescription, so it is important that a doctor checks whether the medication is suitable for you.

Please note: We no longer offer Lariam as it is deemed less convenient and causes more severe side effects than other malaria tablets. We offer the safer alternatives Malarone, doxyxycline and chloroquine.

What is Mefloquine

How does mefloquine prevent malaria?

Mefloquine kills the malaria parasite once it enters the red blood cells and prevents it from multiplying. It is not currently known how exactly mefloquine fights the malaria parasite but it has been found to be highly effective and is often used to prevent infection with Plasmodium falciparum, the most severe type of malaria. Mefloquine can be sometimes be used when travelling to areas where the parasite has become resistant to the antimalarial chloroquine.

What is the difference between mefloquine and other antimalarials?

Unlike most malaria tablets, mefloquine does not need to be taken on a daily basis but only once a week. However, it is very important to take the weekly dose on the correct day to stay protected. While most malaria tablets can be taken regardless of which activities you are going to take part in, mefloquine should not be taken when planning to go scuba diving. Mefloquine is also not recommended for travellers who are going to visit a high altitude region.

Taking Mefloquine

How is mefloquine taken?

You need to take one mefloquine tablet per week. It is very important that you take every dose on the correct day, otherwise you won’t be protected from malaria. You need to take the first dose ten days and the second three days before departure. Your course will be a minimum of six weeks long, as you have to continue taking mefloquine for four weeks after your return. If you notice that you don’t tolerate the tablets, speak to your doctor who will be able to recommend an alternative antimalarial medication. It is very unlikely that you will get malaria if you take your tablets as advised and take precautions to avoid mosquito bites. However, you still need to see a doctor without delay should you experience malaria symptoms during or after your trip.

Who can use mefloquine to prevent malaria?

Mefloquine is a prescription medication and it is not suitable for everyone. It is not recommended if you will be travelling to a high altitude region or if you will be going scuba diving. You also can’t take mefloquine if you are going to pilot an aircraft.

You must not take mefloquine if you have ever suffered from depression or any other mental health issue such as anxiety disorder, psychosis or schizophrenia. Mefloquine tablets are also not suitable for anyone who suffers from epilepsy, has a severe liver or kidney problem or has ever suffered from blackwater fever. You also can’t take mefloquine tablets if you have ever suffered an allergic reaction to a similar medication, such as chloroquine, quinine or quinidine.

Mefloquine is not suitable for preventing malaria in women who are breastfeeding or pregnant. Make sure you use adequate contraception while taking the tablets. You should wait until three months after taking the last tablet before you try to conceive.

Before taking mefloquine, tell your doctor if you:

  • suffer from epilepsy or seizures
  • suffer from a heart problem
  • have a kidney or liver problem
  • have an eye problem
  • have recently had an abnormal blood test
  • experience pins and needles, feel dizzy, shaky or clumsy
  • show signs of an inflammation of the lung, such as fever, cough, chills or chest pain
  • have previously caught malaria despite taking mefloquine tablets

Side Effects of Melfloquine

The use of mefloquine can cause side effects in some people.

Very common side effects

  • insomnia, bad dreams

Common side effects

  • dizziness
  • headache
  • problems with your vision
  • loss of balance or vertigo
  • feeling sick (nausea)
  • stomach ache, nausea and vomiting
  • diarrhoea, stomach ache
  • itching

Other side effects (frequency not known)

  • lack of appetite
  • forgetfulness
  • fainting
  • difficulty talking
  • blurred vision
  • ringing in the ears or other changes to your hearing
  • changes to your heart rate or blood pressure level
  • hot flushes, breathlessness
  • muscle and joint pains
  • hair loss
  • psychological disturbance such as anxiety, paranoia, depression, hallucinations: see below

For a full list of all possible side effects, read the patient leaflet supplied with your mefloquine tablets.

Stop taking mefloquine and speak to you doctor immediately if you experience:

  • allergic reaction (may cause symptoms such as difficulty breathing, swelling, rash and itching)
  • changes in the texture of your skin, eyes and mouth
  • fever, chills, cough, chest pain
  • tender or enlarged liver, jaundice or abnormal blood test results indicating a liver problem
  • dark urine, light stools, generalised itching
  • palpitations
  • feeling weak
  • numbness, pins and needles, shaking of hands or fingers
  • mouth ulcers, bruises or nosebleeds
  • vaginal bleeding or bleeding in the stomach
  • mood changes or psychiatric side effects (see below)

Does mefloquine cause psychiatric side effects?

Mefloquine can cause psychiatric side effects in some people. It is important that you speak to a doctor if you notice any changes in your mood while taking the medication.

Stop taking mefloquine and seek medical help immediately if you experience any of the following:

  • depression
  • anxiety
  • panic attacks
  • suicidal thoughts or attempted suicide
  • risk taking behaviour
  • losing touch with reality
  • feelings of mistrust towards others
  • restlessness
  • hallucinations
  • unusual behaviour or mood changes
  • confusion
  • agitation
  • unusual aggression and anger
  • difficulty concentrating

Driving and operating machinery

Mefloquine can have an impact on your ability to drive and operate machinery. It is therefore not recommended that you take it if you will be piloting an aircraft. Mefloquine tablets can cause dizziness, psychiatric side effects as well as loss of balance. Scuba diving is therefore unsafe if you are taking mefloquine. Do not perform any tasks which require concentration and coordination if you notice any of these side effects.

Drug Interactions

Mefloquine tablets can interact with other medications. make sure you mention all medications you are currently taking or have recently taken to your doctor when you request your prescription.

  • halofantrine
  • blood pressure medication
  • medications to treat heart problems
  • antihistamines
  • medication for psychiatric problems, for example antidepressants
  • medications to treat epilepsy or seizures
  • ketoconazole
  • antibiotics
  • the painkiller tramadol
  • medications to treat blood clotting disorders or diabetes
  • efavirenz (used to treat HIV infections)

If you require an oral typhoid vaccination before travelling you must ensure that you get vaccinated at least three days before you need to start taking mefloquine (as mefloquine can stop the vaccine from working).

For a detailed list of possible drug interactions, read the patient leaflet.

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