Anti-infective
Antimalarials
Antimalarial drugs (malaria prevention and treatment) — Drugs used to prevent and treat malaria — the right choice depends on the region, parasite resistance and whether you are preventing or treating infection.
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
Quick answer
What is Antimalarials?
Antimalarials are a group of medicines used to stop you catching malaria when travelling to risk areas (prophylaxis) and to treat the infection if it occurs. They are not interchangeable: which drug is suitable depends on where you are going, the local pattern of drug resistance, whether the treatment is for prevention or for an established infection, and how severe that infection is.
- How it works: Malaria is caused by Plasmodium parasites carried by mosquitoes.
- In practice: In practice, prophylaxis choice follows up-to-date country and resistance maps rather than habit, and the regimen must be started before travel, taken throughout, and continued for the recommended period after returning — stopping early is a common cause of breakthrough infection.
What it is
Antimalarials are a group of medicines used to stop you catching malaria when travelling to risk areas (prophylaxis) and to treat the infection if it occurs. They are not interchangeable: which drug is suitable depends on where you are going, the local pattern of drug resistance, whether the treatment is for prevention or for an established infection, and how severe that infection is. Some are taken as tablets for travel, while severe malaria is a medical emergency treated in hospital.
How it works
Malaria is caused by Plasmodium parasites carried by mosquitoes. Antimalarials work in different ways: some (such as chloroquine and quinine) interfere with the parasite inside red blood cells, artemisinin-based drugs such as artesunate kill blood-stage parasites very rapidly, and others (such as proguanil and pyrimethamine) block folate pathways the parasite needs. A separate group — primaquine and tafenoquine — clears the dormant liver forms of Plasmodium vivax and P. ovale that other drugs leave behind, which is why they are used to prevent relapse.
In practice
In practice, prophylaxis choice follows up-to-date country and resistance maps rather than habit, and the regimen must be started before travel, taken throughout, and continued for the recommended period after returning — stopping early is a common cause of breakthrough infection. Severe or falciparum malaria is treated with intravenous artesunate in hospital under specialist care, never with oral tablets at home. Before prescribing primaquine or tafenoquine, check G6PD status, because both can trigger serious haemolysis in deficient patients. Mefloquine carries well-known neuropsychiatric cautions and is avoided in people with a history of depression, anxiety or seizures. Pregnancy narrows the options considerably, so seek specialist travel-medicine advice early.
Examples
Practical use
How to take it & use it well
- Start the tablets before you travel, keep taking them every day or week exactly as directed while away, and continue for the full period after returning, as stopping early leaves you unprotected.
- Take them at the same time each day or week with food and a full glass of water, which helps them work and reduces stomach upset.
- Remember that no tablet is completely protective, so always combine them with bite-avoidance measures such as repellent, covering up at dusk and dawn, and sleeping under a treated net.
- Choose the right tablet for your destination with a travel clinic or pharmacist, as which medicine works depends on where you are going and the local malaria pattern.
- If you are taking the antibiotic option that also prevents malaria, follow the usual advice for that antibiotic, including sun protection and keeping it away from indigestion remedies and milk.
- Any fever or flu-like illness during your trip or for up to a year after returning needs urgent medical attention, and you should mention that you have travelled to a malaria area.
Common uses
- Prevention of malaria for travellers (prophylaxis)
- Treatment of uncomplicated malaria
- Treatment of severe/falciparum malaria (IV artesunate, hospital)
- Clearing dormant liver parasites to prevent relapse
Monitoring
- G6PD testing before primaquine or tafenoquine
- Mood and mental state on mefloquine
- Clinical response, parasite clearance and recovery when treating active infection
Weighing it up
Advantages & disadvantages
Advantages
- Taken correctly alongside bite avoidance, they greatly reduce the risk of catching malaria, which can be life-threatening.
- There are several options, so a suitable one can usually be found for your destination and health.
- Some can be started just a day or two before travel, which is convenient for last-minute trips.
- One option is a once-weekly tablet, which is easier to remember for longer trips.
- They are well established and can be advised by a travel clinic or pharmacist tailored to your journey.
Disadvantages
- No antimalarial is completely effective, so they must always be combined with measures to avoid mosquito bites.
- They can cause side effects such as stomach upset, and some can cause vivid dreams or mood changes.
- They have to be taken consistently before, during and after travel, which is easy to forget.
- The right choice depends on your destination, health and other medicines, so they need proper advice.
- One option that prevents malaria also makes the skin more sensitive to the sun, requiring extra sun protection.
Key safety principles
What to watch for
- Test G6PD status before primaquine or tafenoquine — these can cause severe haemolysis in deficiency.
- Mefloquine can cause neuropsychiatric effects; avoid where there is a history of depression, anxiety or seizures.
- Severe or falciparum malaria is a medical emergency for IV treatment in hospital, not oral self-treatment.
- Pregnancy and breastfeeding restrict which agents are safe — take specialist advice.
- Prophylaxis only protects if started before travel and continued for the full recommended period afterwards.
- Several agents interact with other drugs and can affect the heart rhythm — check before co-prescribing.
Key interactions
What to avoid or check alongside
- The antibiotic option that prevents malaria binds to milk, antacids and iron, so these should be kept separate from the tablet.
- Some antimalarials interact with medicines used for the heart, epilepsy or mood, so all your medicines should be reviewed before travel.
- Indigestion remedies and antacids can affect how some antimalarials are absorbed if taken at the same time.
- Alcohol can add to side effects such as drowsiness or stomach upset with some of these tablets.
- Tell the travel clinic about any history of depression, seizures or heart-rhythm problems, as this affects which tablet is safe for you.
Patient & carer advice
- Start prophylaxis before you travel and keep taking it for the full period after you return
- Use mosquito bite-avoidance measures as well — no tablet is fully protective
- Seek urgent medical help for any fever during or up to a year after travel
- Report low mood, anxiety or disturbing dreams if you are taking mefloquine
Answers
Antimalarials: frequently asked questions
Do malaria tablets give complete protection?
No antimalarial is one hundred per cent effective, so even when you take them correctly you can still catch malaria. That is why you must also avoid mosquito bites using repellent, covering up at dawn and dusk, and sleeping under a treated net.
Why do I have to keep taking them after I get home?
Malaria parasites can still be developing in your body after you leave the area, so the tablets must be continued for the full period after travel to clear them. Stopping early leaves you at risk even once you are home.
I've come back from a malaria area and have a fever — what should I do?
Any fever or flu-like illness during your trip or for up to a year afterwards could be malaria and needs urgent medical attention. Tell the doctor where you have travelled, as malaria can become serious very quickly.
How do I know which malaria tablet to take?
The right tablet depends on where you are going, as malaria resistance varies between regions, and on your own health and other medicines. A travel clinic, GP or pharmacist can recommend the most suitable option for your trip.
When should I start taking them?
It depends on the tablet: some are started a day or two before travel, while others need to begin a week or more beforehand. Get advice in good time before your trip so you can start at the right point and pick up the correct medicine.
Authoritative sources
Always verify against the source
This overview is for orientation. For doses, interactions, contra-indications and the full monograph, use:
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