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Chloroquine tablets and liquid medicine

Avloclor, Malarivon

If you are taking chloroquine to protect against malaria, it is important that you take it once a week, exactly as you have been told. Start taking it one week before you travel, then during the whole of your stay, and continue to take it for four weeks after you return.

Store chloroquine safely out of the reach and sight of children. Chloroquine is very harmful in overdose or if ingested accidentally.

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About chloroquine

Type of medicine

An antimalarial

Used for

Malaria; rheumatoid arthritis or lupus erythematosus

Also called

Avloclor® (chloroquine phosphate); Malarivon® (chloroquine phosphate)

Available as

Tablets and liquid medicine

Chloroquine is mainly used to protect against malaria when people travel to areas where this can be a problem. It is usually used in combination with another antimalarial medicine to increase its effectiveness. It is also used to treat people who have a form of malaria called non-falciparum malaria.

Malaria is a serious infection. It is common in tropical countries such as parts of Africa, Asia, South and Central America, and the Middle East. Malaria is a disease which is passed on to humans by infected mosquitoes. A parasite called plasmodium lives inside the stomachs of infected female mosquitoes and is passed on to humans by a bite.

Because the pattern of malaria varies with the part of the world you are travelling to, as well as the season and the type of activity you have planned, you should always obtain the latest advice about malaria prevention from your doctor, pharmacist or travel organiser. A backpacking trip may well require different preventative measures against malaria to those needed for a business trip to a city.

Chloroquine is not prescribable on the NHS in order to prevent malaria, but you are able to buy the tablets at pharmacies, without a prescription, for this purpose.

Chloroquine is available on prescription to treat rheumatoid arthritis and lupus erythematosus, although other treatments are usually preferred. These are both autoimmune diseases. This means that your immune system (which normally protects your body from infections) mistakenly attacks itself. This causes pain and damage to parts of your body. Chloroquine is used in some people to help reduce the damage these conditions can cause.

Before taking chloroquine

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking chloroquine it is important that your doctor or pharmacist knows:

  • If you are pregnant or breastfeeding. Travel to areas with malaria is best avoided during pregnancy. If the travel is unavoidable, you will be advised to take chloroquine even if you are pregnant.

  • If you have any problems with the way your kidneys work, or any problems with the way your liver works.

  • If you have a heart condition, such as heart disease or an irregular heartbeat.

  • If you have ever had epilepsy.

  • If you have a skin condition called psoriasis.

  • If you have a condition which causes severe muscle weakness, called myasthenia gravis.

  • If you have problems with your stomach or intestines.

  • If you have either of these rare inherited conditions: a blood disorder called porphyria, or glucose-6-phosphate dehydrogenase (G6PD) deficiency (this is a disorder which causes problems after eating some foods, such as fava beans).

  • If you are taking any other medicines. This includes any medicines which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic reaction to a medicine.

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How to take chloroquine

  • Before you take chloroquine, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about the medicine, and will also provide you with a full list of the side-effects which you could experience from taking it.

  • It is important that you take chloroquine exactly as you have been directed. Your doctor or pharmacist will tell you how much to take, and how often to take it. The directions will also be printed on the label of the pack to remind you about what was said to you. Chloroquine should be taken with food. Swallow the tablets with a drink of water.

  • If you take a medicine for indigestion (such as an antacid), do not take it within two hours, either before or after, of taking chloroquine. This is because antacids interfere with the way chloroquine is absorbed by your body, making it less effective.

  • If you have been advised to have an oral vaccine to protect you against typhoid, you should arrange to have this so your course is finished at least three days before you start taking chloroquine. This is because chloroquine can stop the vaccine from working properly.

  • If you suspect that you have taken an overdose of chloroquine, or that someone else (especially if it is a child) might have taken it accidentally, go to the accident and emergency department of a local hospital straightaway. This is very important because chloroquine can cause serious problems when it is taken accidentally or in overdose. Take the container with you to show what has been taken, even if the pack is now empty.

If you are taking chloroquine to protect against malaria

  • You should take the first dose of chloroquine a week before entering an area where malaria occurs. This is to ensure there is sufficient medicine in your bloodstream to give you the required protection. You should continue to take chloroquine throughout your stay and for a further four weeks after you have left the area.

  • Take the tablets (or medicine) exactly as your doctor or pharmacist has told you. The dose for an adult is two tablets once a week, on the same day of the week. If the chloroquine is for a child, read the directions on the label carefully, as their dose will depend upon their age and weight.

  • If you forget to take a dose on the correct day, take it as soon as you remember and then wait seven days before you take your next dose.

  • You should complete the full course of tablets (or medicine). This means making sure that you remember to take chloroquine for four weeks after your visit is over.

  • Chloroquine will help reduce the risk of you getting malaria, but it is also important that you take the following precautions against being bitten by mosquitoes:

    • Cover up bare areas of your arms and legs with long-sleeved, loose-fitting clothing, long trousers and socks. This is especially important if you are outside after sunset, as this is when mosquitoes feed.

    • Use an effective insect repellent spray on your clothing and any area of your skin which is bare. If you are also using a sunscreen, apply the sunscreen first and the insect repellent afterwards.

    • Spray the room with an insecticide each evening a couple of hours before you go to bed. Check your sleeping areas for mosquitoes - pay particular attention to furniture and areas under your bed where insects can hide.

    • If you are sleeping in an unscreened room, use a mosquito net impregnated with an insecticide.

  • If you feel ill or develop a high temperature (fever) or flu-like symptoms while you are travelling or within one year (especially if it is within three months) of returning home, you should see your doctor straightaway. This is important, even if you have taken your antimalarial tablets correctly.

If you are taking chloroquine for rheumatoid arthritis or lupus erythematosus

  • It is usual to take chloroquine once daily, although some people could be advised to take it twice daily for a short period of time. Your dose will be adjusted to suit you, so it is important that you follow the directions given to you by your doctor or specialist; for most people the dose is likely to be one tablet a day. The directions will be printed on the label of the pack to remind you about what the doctor said to you.

  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. Your doctor is likely to check your vision before you start the treatment, and then regularly thereafter. This is because chloroquine can affect your eyesight when taken over a long period of time. If you notice any changes in your vision, you should inform your doctor as soon as possible so that it can be checked.

  • If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, leave out the forgotten dose from the previous day and take the dose that is due as normal. Do not take two doses on the same day to make up for a missed dose.

Can chloroquine cause problems?

All medicines can cause unwanted side-effects along with their useful effects, although not everyone experiences them. The unwanted effects usually improve as your body adjusts to the new medicine. When chloroquine is used to prevent malaria, side-effects are generally uncommon and not serious. Where chloroquine is taken for a long time, side-effects can be more serious. Speak with your doctor or pharmacist if any of the following continue or become troublesome:

Chloroquine side-effects

What can I do if I experience this?

Feeling sick (nausea) or being sick (vomiting), diarrhoea

Stick to simple foods - avoid spicy or fatty foods


Drink plenty of water and ask a pharmacist to recommend a suitable painkiller.

Feeling dizzy or light-headed

Do not drive and do not use tools or machines until the feeling passes

Hair loss, changes in skin colour, itchy skin rash

If any of these become troublesome, speak with your doctor

Low blood sugar (signs of this are feeling shaky or anxious, sweating, looking pale, feeling hungry, having the sensation of a 'thumping heart' (palpitations), and feeling dizzy)

Eat or drink something containing sugar or have a snack straightaway. Speak with a doctor about this

Chloroquine side-effects when taken long-term

What can I do if I experience this?

Heart changes, blood problems, eyesight problems, hearing problems, mood changes, liver problems

Your doctor will monitor for these, but if you suspect any, please ask for advice straightaway

If you experience any other symptoms which you think may be due to the medicine, speak with a doctor or pharmacist who will advise you further.

Continue reading below

How to store chloroquine

  • Keep all medicines out of the reach and sight of children. Chloroquine is very harmful in overdose or if ingested accidentally.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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