Artemether, lumefantrine (Riamet)
How does it work?
Riamet tablets contain two active ingredients, artemether and lumefantrine. These are both antimalarial medicines.
Malaria is caused by a protozoal parasite called Plasmodium, which is carried by mosquitoes. During a bite from an infected mosquito, the parasite passes into the body. Once inside, it lives and reproduces, resulting in the disease known as malaria.
The malaria parasites have various stages in their lifecycle within the body. After entering the bloodstream during a bite from an infected mosquito, they are carried to the liver where they reproduce. They are then released back into the bloodstream where they infect red blood cells.
In the red blood cells, the malaria parasites digest haemoglobin, the red protein within red blood cells that is responsible for carrying oxygen. When this happens, the haemoglobin is divided into two parts; haem and globin. Haem is toxic to the malaria parasites. They protect themselves from it by producing a substance that converts the toxic haem into a compound called haemozoin, which is not toxic to the parasites.
Artemether and lumefantrine both work by interfering with the ability of the malaria parasites to convert haem into haemozoin. This causes levels of the toxic haem to rise, which kills the blood stages of the malaria parasites and stops the infection from continuing.
Riamet tablets are given to treat malaria caused by Plasmodium falciparum parasites (falciparum malaria or malignant malaria).
What is it used for?
- Treatment of uncomplicated Plasmodium falciparum malaria in adults, children and infants weighing 5kg and above.
- Riamet tablets should be taken with or after food. If the patient can't tolerate food the tablets should still be taken, but they may be less effective. The tablets can be crushed for small children or infants.
- If you are sick within one hour of taking a dose of this medicine you should consult your doctor or pharmacist, as you may need to take another dose.
- It is very important that you complete the prescribed course of this medicine, unless otherwise directed by your doctor, as the medicine may not be fully effective if you don't.
- Unless your doctor or pharmacist tells you otherwise, you should avoid drinking grapefruit juice while taking this medicine, as it may affect the level of this medicine in your blood.
- This medicine may cause fatigue and dizziness. You should take care when performing potentially hazardous activites, such as driving or operating machinery, until you know how this medicine affects you and are sure you can perform such activities safely.
- If you have kidney, liver or heart problems you should be regularly monitored while you are taking this medicine, to check the level of potassium in your blood (blood test), and your heart function (ECG).
Use with caution in
- Severely decreased kidney function.
- Severely decreased liver function.
- Heart disease.
Not to be used in
- Severe malaria according to the World Health Organisation (WHO) definition, eg malaria affecting the brain, or causing pulmonary oedema or kidney failure.
- Family history of sudden death.
- Family history of an abnormal heart rhythm, present from birth, seen on a heart monitoring trace (ECG) as a 'prolonged QT interval'.
- People with diseases or conditions that can cause an abnormal heart rhythm, seen on a heart monitoring trace (ECG) as a 'prolonged QT interval' (your doctor will know), or people taking medicines that can cause this (see end of factsheet).
- History of irregular heartbeats (arrhythmias).
- Slow heart rate (bradycardia).
- Heart failure.
- Disturbances in the levels of salts (electrolytes) in the blood, eg low blood potassium level (hypokalaemia) or low blood magnesium level (hypomagnesaemia).
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 for use during pregnancy has not been established. It should be avoided wherever possible during the first trimester. It should only be used during later stages of pregnancy if the expected benefits to the mother outweigh any risks to the foetus. Seek medical advice from your doctor.
- It is not known if this medicine passes into breast milk. Women who need to take this medicine should not breastfeed during treatment, and for at least a week following their last dose. 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. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Loss of appetite.
- Disturbances of the gut such as nausea, vomiting, diarrhoea or abdominal pain.
- Weakness or loss of strength (asthenia).
- Pain in the muscles and joints.
- Pins and needles or numb sensations.
- Rash or itching.
- Awareness of your heartbeat (palpitations).
- Abnormal heart rhythm.
- Involuntary muscle contractions.
- Shaky movements and unsteady walk (ataxia).
The side effects listed above may not include all of the side effects reported by the drug'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 while taking this one, to ensure that the combination is safe.
The manufacturer states that this medicine should not be taken in combination with any other antimalarial medicine, due to limited data on the safety and efficacy of combination treatment.
The manufacturer states that this medicine must not be taken in combination with the following medicines, because it may increase the amount of these medicines in the blood and increase the chance of their side effects:
The manufacturer states that this medicine must not be taken with any of the following medicines, because the combination may increase the risk of abnormal heart rhythms:
- certain medicines for irregular heart rhythms (antiarrhythmics), eg mexiletine, propafenone, procainamide, disopyramide, amiodarone, quinidine, sotalol
- antidepressant medicines, eg amitriptyline, maprotiline, fluoxetine
- antipsychotic medicines, eg chlorpromazine, thioridazine, haloperidol
- other antimalarials, eg quinine, halofantrine (patients previously treated with halofantrine should not receive this medicine until at least one month after their last halofantrine dose)
- the antihistamines astemizole or terfenadine
- certain anti-infectives, eg erythromycin, clarithromycin, ketoconazole, moxifloxacin, pentamidine, voriconazole.