Most people get mild side effects from malaria tablets, or none at all. Doxycycline can make your skin burn more easily in the sun, Malarone may cause a mild upset stomach or headache, and mefloquine can affect mood and sleep. Whatever you take, use insect repellent and get any fever checked.
Fever after travel could be malaria. Malaria tablets greatly reduce your risk but don't remove it. If you get a high temperature, sweats, chills, headache or flu-like symptoms while travelling or up to a year after you come back, get medical help the same day and say where you've been. Malaria can become serious very quickly.
Related: Malaria tablets: which one and when to start
Malaria tablets used in the UK
The main options
The three tablets most often recommended for UK travellers are:
- doxycycline, an antibiotic taken once a day;
- atovaquone-proguanil (Malarone, and generic versions), taken once a day;
- mefloquine (Lariam), taken once a week.
Chloroquine and proguanil are now rarely recommended, because malaria in most areas has become resistant to them. Which tablet suits you depends on where you're going, how long for, your health, any other medicines you take, and whether you're pregnant or planning a pregnancy.
How long you take them for
| Tablet | Start | How often | Keep taking after you leave | Main side effects | Not usually suitable for |
|---|---|---|---|---|---|
| Doxycycline | 1 to 2 days before | Once a day | 4 weeks | Sun sensitivity, indigestion, heartburn, thrush | Pregnancy, breastfeeding, children under 12 |
| Atovaquone-proguanil (Malarone) | 1 to 2 days before | Once a day | 7 days | Mild stomach upset, headache | Pregnancy, breastfeeding, severe kidney problems |
| Mefloquine (Lariam) | 2 to 3 weeks before | Once a week | 4 weeks | Vivid dreams, poor sleep, dizziness, anxiety or low mood | People with depression, anxiety, other mental health conditions or epilepsy, now or in the past |
Starting mefloquine early lets you see whether you get side effects before you travel, while there's still time to switch.
Don't forget bite prevention
No tablet is 100% effective. Use an insect repellent containing 50% DEET, sleep under a treated mosquito net, and cover up with long sleeves and trousers from dusk to dawn. UK guidance sums this up as the ABCD of malaria prevention: Awareness of risk, Bite prevention, Chemoprophylaxis (tablets) and prompt Diagnosis.
Common side effects
Stomach upset
Feeling sick, indigestion, stomach ache and diarrhoea are the most common side effects of all malaria tablets. They're usually mild and often settle after the first few doses. Taking your tablet with food helps.
If you're sick within an hour of taking a dose, check the leaflet or ask a pharmacist, as you may need to take another.
Headaches and dizziness
Headaches are common when you first start and usually ease. Some people feel light-headed, especially in hot weather or if they're dehydrated, so drink plenty of water. If you feel dizzy, don't drive, dive or climb at heights until it passes. Speak to a doctor or pharmacist if headaches or dizziness are severe or don't settle.
Skin reactions and sun sensitivity
Doxycycline in particular makes your skin more sensitive to sunlight, so you can burn more quickly and more badly than usual. This matters in the tropics, where strong sun is hard to avoid. Rashes and itching can happen with any malaria tablet.
Side effects by tablet
Doxycycline
Doxycycline is an antibiotic that also prevents malaria. Its main side effect is sun sensitivity: use a high-factor sunscreen, cover up and stay in the shade around midday.
It can also cause indigestion and heartburn, and it can irritate the gullet (oesophagus) if a capsule gets stuck. Take it with a full glass of water, while sitting or standing, and stay upright for at least 30 minutes, so don't take it just before bed. Don't take it at the same time as milk, indigestion remedies, or iron, calcium or zinc supplements, as these stop it being absorbed properly. Leave a gap of 2 to 3 hours.
Because it's an antibiotic, doxycycline can cause vaginal thrush in some women. Thrush treatment from a pharmacy usually clears it. Alcohol is best avoided while you take it; our post on alcohol and antibiotics explains why.
MedsRus supplies doxycycline for malaria prevention after an online consultation.
Atovaquone-proguanil (Malarone)
Malarone is usually very well tolerated. The most common side effects are a mild upset stomach, headache and dizziness. Taking it with food or a milky drink, at the same time each day, helps it work and reduces sickness. Mouth ulcers, a cough and odd dreams are less common.
Its main practical advantage is that you only need to keep taking it for 7 days after leaving a malaria area, rather than 4 weeks.
Mefloquine (Lariam)
Mefloquine has the most concerning side effects of the three, mainly on mood, sleep and the nervous system. Vivid dreams, nightmares and trouble sleeping are common. Some people get anxiety, low mood, panic attacks, dizziness or problems with balance.
Because of this, mefloquine isn't suitable if you have, or have had, depression, anxiety, psychosis or another mental health condition, or epilepsy. Tell your prescriber about any of these. You should be given a patient alert card with your tablets: carry it with you. Don't drive, dive or do anything that needs good balance if you feel dizzy.
Serious but rare side effects
Mental health effects
Serious mental health reactions are rare but important. They include severe anxiety, depression, paranoia, hallucinations, confusion and thoughts of self-harm. Mefloquine carries the highest risk, and the effects can start during the course or after stopping, and occasionally last for a long time.
If you or someone travelling with you notices any of these, stop taking mefloquine and get medical help straight away. Ask about switching to a different tablet.
Seizures are a very rare side effect, mainly with mefloquine, which is why it isn't used in people with epilepsy.
Heart rhythm effects
Mefloquine can occasionally affect heart rhythm. Tell your prescriber if you have a heart rhythm problem or take medicines that affect heart rhythm. Palpitations, chest pain, fainting or severe dizziness need urgent medical advice.
Severe allergic reactions
Any medicine can cause a severe allergic reaction (anaphylaxis), though this is rare. Call 999 or get emergency help if you have swelling of the lips, mouth, throat or tongue, difficulty breathing, or a widespread rash.
Very rarely, malaria tablets can cause a serious skin reaction with blistering and peeling of the skin, mouth or eyes. This needs emergency treatment. Milder rashes are more common; get advice from a doctor or pharmacist about whether to carry on.
If you get malaria
Prevention tablets are different from the medicines used to treat malaria. If you do get malaria, it's treated urgently by a doctor, often in hospital, with different medicines. Our guide to how malaria is treated explains more.
Keeping side effects to a minimum
.webp)
Take your tablets with food
Taking malaria tablets with a meal reduces stomach upset for most people. Malarone works best with food or a milky drink. Take doxycycline with food and a full glass of water, but away from milk and indigestion remedies. Take mefloquine after a meal with plenty of water.
Get the timing right
- Take daily tablets at the same time each day, so you don't forget.
- Take doxycycline in the morning or with your evening meal, not just before bed.
- For mefloquine, choose a day of the week you'll remember, such as every Sunday with breakfast.
- If a tablet makes you feel drowsy or gives you odd dreams, ask your pharmacist whether you can change the time you take it.
When to get advice
Mild sickness, a slight headache or vivid dreams don't usually mean you need to stop. Protection from malaria matters more. But speak to a doctor or pharmacist if side effects are severe, stop you getting on with your trip, or haven't settled after the first week. Switching to a different tablet often helps. Don't just stop taking your tablets without getting advice on an alternative.
Get medical help straight away for a severe allergic reaction, serious mental health symptoms, chest pain or fainting, and for any fever during or after travel.
Getting malaria tablets
Get advice 6 to 8 weeks before you travel if you can, as you may need vaccines too. MedsRus supplies doxycycline for malaria prevention after an online consultation; we don't supply Malarone or mefloquine, which you can get from a travel clinic, GP or other pharmacy. Our malaria tablets page explains how doxycycline is taken and how many you need for your trip.
Malaria tablet side effects FAQs
Which malaria tablet has the fewest side effects?
Atovaquone-proguanil (Malarone) is usually the best tolerated, and doxycycline is also well tolerated by most people apart from sun sensitivity. Mefloquine is more likely to affect mood and sleep. The right choice also depends on where you're going, your health and other medicines.
Can doxycycline make you burn in the sun?
Yes. Doxycycline makes your skin more sensitive to sunlight, so you can burn more quickly. Use a high-factor sunscreen, cover up and stay in the shade around midday. Stop taking it and get advice if you get a severe sunburn-like rash.
Do malaria tablets cause bad dreams?
Vivid dreams and trouble sleeping are common with mefloquine and occasionally happen with Malarone. If you have frightening dreams, low mood, anxiety or feel confused on mefloquine, stop taking it and get medical advice about switching.
Can I drink alcohol with malaria tablets?
It's best to avoid alcohol with doxycycline, as it may make it less effective in heavy drinkers. Alcohol can also make dizziness and sickness worse with any malaria tablet. Keep it light, and drink plenty of water in hot climates.
Why do I need to keep taking tablets after I get home?
Some malaria parasites take time to develop in the liver before they reach the blood. Continuing the tablets after you leave (4 weeks for doxycycline and mefloquine, 7 days for Malarone) protects you during that time.
Sources: