Proguanil, atovaquone (Malarone)
How does it work?
Malarone tablets contain two active ingredients, proguanil hydrochloride and atovaquone. These are both medicines that are active against the parasite that causes malaria.
Malaria is a potentially fatal disease caused by various types of parasites known as Plasmodium. Plasmodium are carried by mosquitoes and injected into the bloodstream during a bite from an infected mosquito. Once inside the body the parasite reproduces, resulting in the disease.
Proguanil hydrochloride works by stopping the parasite from reproducing once it is in the bloodstream. It does this by blocking the action of a compound that is found in the Plasmodium parasite. This compound is an enzyme called dihydrofolate reductase, and is involved in the reproduction of the parasite.
Dihydrofolate reductase normally converts folic acid into folinic acid in the parasite, which is a step essential for the parasite to produce new genetic material (DNA). New DNA is necessary for the parasite to reproduce. By blocking it's production, proguanil prevents malarial parasites in the blood from reproducing and increasing in number.
Atovaquone also works by interfering with the production of substances needed by the malarial parasites to reproduce. It works in a slightly different way however, so these two medicines work in combination against the Plasmodium parasite.
Proguanil with atovaquone is used to prevent malaria caused by a type of Plasmodium called Plasmodium falciparum. This parasite produces the most serious form of malaria (malignant malaria). Proguanil with atovaquone may be particularly useful for preventing malaria in travellers to areas where this parasite is known to be resistant to other antimalarial medicines, such as chloroquine. Click here to see if Malarone is recommended to prevent malaria in the country you are visiting.
Higher doses of proguanil and atovaquone are also used to treat uncomplicated malaria caused by infection with the Plasmodium falciparum parasite. However, this combination of medicines has not been evaluated for the treatment of more complicated or severe malaria, affecting the brain, lungs or kidneys.
What is it used for?
- Preventing Plasmodium falciparum malaria in people weighing over 40kg.
- Treating uncomplicated Plasmodium falciparum malaria in adults, and in children weighing between 11kg and 40kg.
How do I take it?
- To prevent malaria in people who weigh over 40kg, one Malarone tablet should be taken once a day. You should start taking the medicine 24 to 48 hours before entering the malarial area. You should continue taking one tablet a day throughout your stay and for 7 days after leaving the area.
- Take the tablet at the same time each day with food or a milky drink.
- If you vomit within one hour of taking a tablet, take another tablet then go on as before. If this happens you will need to contact your doctor to replace the tablet you brought up.
- To prevent malaria it is important that this medicine is taken regularly. Try not to forget a dose. However, if you do forget to take a dose, dont worry, just take your next dose as soon as you remember, then continue your treatment as before. Dont take a double dose to make up for a missed dose.
- You should still take precautions to avoid being bitten by mosquitos, such as using mosquito repellants and sleeping under mosquito nets. This is particularly important if you have vomiting or diarrhoea, because this could make the tablets less effective. If you fall ill within one year of your return, and especially if within three months of your return, you should consult your doctor immediately and let him know that you have visited a country where malaria is endemic.
- To treat malaria in adults, a dose of four Malarone tablets should be taken every day for three consecutive days.
- The dose to treat malaria in children depends on how much the child weighs. Children weighing 11kg to 20kg should take one tablet daily for three consecutive days. Children weighing 21kg to 30kg should take two tablets daily for three consecutive days. Children weighing 31kg to 40kg should take three tablets daily for three consecutive days. Children weighing over 40kg should take the same dose as adults (four tablets daily for three consecutive days).
- The tablets should be taken at the same time each day with food or a milky drink.
- If you vomit within one hour of taking a dose, repeat that dose then go on as before. If this happens you will need to contact your doctor to replace the tablet(s) you brought up.
- To prevent malaria it is important that this medicine is taken regularly. Try not to forget a dose. You should still take precautions to avoid being bitten by mosquitos, such as using mosquito repellants and sleeping under mosquito nets. This is particularly important if you have vomiting or diarrhoea, because this could make the tablets less effective. If you fall ill within one year of your return, and especially if within three months of your return, you should consult your doctor immediately and let him know that you have visited a country where malaria is endemic.
- If you get Plasmodium falciparum malaria despite using this medicine for prevention, or if your malaria comes back after being treated with this medicine, the infection should be treated with a different antimalarial. You should make sure your doctor knows that you have been taking Malarone.
Use with caution in
- Treatment of malaria in people with severely decreased kidney function (this medicine should only be used if there are no suitable alternatives).
- Treatment of malaria in people with diarrhoea and vomiting (the patient's condition must be monitored closely, because vomiting and diarrhoea could make this medicine less effective at treating the malaria).
Not to be used in
- Prevention of malaria in people with severely decreased kidney function.
- Malarone tablets are not recommended for preventing malaria in people who weigh less than 40kg, or for treating malaria in children who weigh less than 11kg. Malarone paediatric tablets can be used for this age group (see factsheet linked at end of page).
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine in pregnancy has not been established. It should be used with caution during pregnancy, and only if the benefits to the mother outweigh any risks to the developing baby. Seek further medical advice from your doctor.
- It is not known if atovaquone passes into breast milk. Proguanil passes into breast milk in small amounts. The manufacturer states that Malarone should not be used by breastfeeding mothers. Seek further medical advice from your doctor.
- Take this medication with or after food.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Very common (affect more than 1 in 10 people)
- Disturbances of the gut such as nausea, vomiting, diarrhoea or abdominal pain.
Common (affect between 1 in 10 and 1 in 100 people)
- Loss of appetite.
- Difficulty sleeping (insomnia).
- Abnormal dreams.
- Rash or itching.
- Low red blood cell count (anaemia).
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Inflammation of the lining of the mouth (stomatitis).
- Hair loss (alopecia).
Frequency not known
- Mouth ulcers.
- Low blood sodium level (hyponatraemia).
- Decrease in the number of a type of white blood cell (neutrophil) in the blood (neutropenia).
- Allergic reactions such as rash, or severe swelling of lips, face or tongue (angioedema).
- Severe skin reactions such as blistering, peeling or increased sensitivity to sunlight.
- Inflammation of the liver (hepatitis).
- Increased heart rate.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines in combination with this one, to make sure that the combination is safe.
The amount of atovaquone in the blood may be reduced by the following medicines. If you are taking one of these it could make Malarone less effective at preventing and treating malaria:
- efavirenz and ritonavir-boosted protease inhibitors for HIV infection (Malarone should preferably be avoided in people taking one of these medicines)
- metoclopramide (a different anti-sickness medicine should be used in people taking Malarone)
- rifampicin and rifabutin (these medicine are not recommended for people taking Malarone)
Atovaquone may decrease the blood level of the anti-HIV medicine indinavir.
Atovaquone may increase the blood level of the anti-HIV medicine zidovudine and the chemotherapy medicine etoposide. It could increase the risk of side effects from these medicines.
Proguanil may enhance the anti-blood-clotting effect of the anticoagulant medicine warfarin. If you are taking warfarin, your blood clotting time (INR) should be checked after you start and stop taking Malarone and, based on the results, your warfarin dose may need adjusting.
Malarone is not recommended for people taking histamine for leukaemia.
The antacid magnesium trisilicate may reduce the absorption of proguanil from the gut if it is taken at the same time of day. If you need to take a magnesium-containing antacid while you are taking Malarone, you should not take it at the same time of day; the doses should be separated by at least three hours.
Other medicines containing the same active ingredients