Medication Information Leaflet

​What is this medication for?

Chloroquine is a medication used to prevent malaria. It may also be used for other conditions as determined by your doctor and not listed in this leaflet.

Malaria is a disease caused by a parasite (Plasmodium species), which can be spread to humans by the bite of an infected female Anopheles mosquito.

How should I take/use this medication?

  • The medication is usually taken once every week, preferably on the same day of the week, unless directed otherwise by your pharmacist or doctor.
  • This medication should be taken with or after meals.
  • In children, the dosage is preferably calculated by body weight. Check with your pharmacist or doctor for the correct dose for your child.
  • Start at least one week before entering the area with malaria risk, continue to take the medication once a week during the trip. After leaving the area with malaria risk, continue to take the medication for four consecutive weeks after travel or once you return to Singapore. It is important to complete the full course of medication for complete protection.
  • Do not stop taking your medication before checking with your healthcare professional. 

What should I do if I forget to take/use this medication?

If you forget to take a dose, take it as soon as you remember. However, if it is near the time for your next dose, skip the missed dose and go back to your usual schedule. Do not take two doses to make up for the missed dose. 

What precautions should I take?

You must ask your doctor or pharmacist if this medication is suitable for the region that you are travelling to as chloroquine resistance may be widespread for some geographic areas. 

Inform your healthcare professional if: 

  • You are allergic to chloroquine or any of the other ingredients of this medication.
  • You are pregnant or breast-feeding.
  • You are taking any other medications, including supplements, traditional medications and herbal remedies.
  • You have problems with your vision or hearing.
  • You are taking chloroquine for a prolonged period of time.
  • Have a history of the following conditions:
    • Seizures (epilepsy or fits).
    • Heart rhythm disorders.
    • Glucose-6-phosphate dehydrogenase (G6PD) deficiency.
    • Psoriasis, a long term inflammatory skin disease.
    • Porphyria, a group of disorders that can cause nerve or skin problem.
    • Myasthenia Gravis, a long term neuromuscular disorder causing muscle weakness.
    • Liver problems.
    • Kidney problems.

What are some common side-effects of this medication?

  • You may experience nausea, vomiting, stomach pain.
    • Take the medication after food to reduce gastric side effects.
  • You may experience redness, discolouration or severe sunburn of the skin.
    • This may be a result of your skin becoming more sensitive to sunlight.
    • Avoid prolonged sun exposure (especially between 10am - 3pm). Wear protective clothing or apply sunblock where necessary and do not use a sunlamp.
  • You may experience headache or insomnia.
    • You should continue taking the medication unless you are unable to stand the side effects.
  • You may experience signs of dizziness or blurred vision.
    • If affected, do not drive or operate any machinery or tools. Inform your doctor or pharmacist if signs of eye problems occur (refer to Section 5).
    • Your doctor may suggest that you have eye tests if you are taking chloroquine for a long period of time.

What are some rare but serious side-effects that I need to seek medical advice immediately?

  • Changes in your behaviour
    • Changes in your mood such as feeling depressed, anxious or confused.
    • Seeing, feeling or hearing things that are not there (hallucinations). 
  • Blood disorders
    • Symptoms include unusual bleeding or bruising, lip or mouth ulcers with ‘flu-like’ symptoms such as stuffy or runny nose and cough. However, some patients may not experience any symptoms.
    • Anemia, a condition where you do not have enough red blood cells, may present with worsening tiredness, rapid breathing, pale skin/lips/nails, fast heartbeat while resting. 
  • Central nervous system effects
    • Sudden tremors.
    • Uncontrolled muscle movement or spasms.
    • Muscle weakness.
    • Seizures or fits
  • Eye problems
    • Trouble focusing, blurred vision or difficulty in reading.
    • Some or complete loss of eyesight, or ‘patch’ eyesight.
    • Light streaks or flashes in vision.
    • Problems with color vision.
  • Hearing loss or ringing in the ears
  • Heart problems
    • Uneven heartbeats with or without breathlessness.
    • Swollen feet, ankles or legs.
    • Fatigue. 
  • Liver problems
    • Symptoms include dark urine or light coloured stools, nausea, vomiting, loss of appetite, stomach pain, yellowing of your eyes or skin.
  • Low blood sugar
    • Shaky or feeling anxious.
    • Fast heartbeat.
    • Dizziness. 
  • Skin-related symptoms
    • Severe widespread rash with blisters and peeling skin, particularly occurring around the mouth, nose, eyes and genitals (Stevens-Johnson syndrome).
    • Fever with a rash and/or swollen lymph glands, which may lead to inflammation of organs such as the liver, kidney, lungs, heart, or pancreas.
  • Drug allergy (symptoms include one or more of the following)
    • Swollen face/eyes/lips/tongue.
    • Difficulty in breathing.
    • Itchy skin rashes over your whole body.

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take this medication?

Inform your pharmacist or doctor if you are taking any of the medications below:

  • Amiodarone (used to treat irregular heart beat)
  • Antacids and kaolin (used to neutralize gastric acid)
  • Cimetidine (used to reduce gastric acid production)
  • Insulin or other antidiabetic drugs
  • Anti-convulsant medicines (used to prevent fits).
  • Medications known to affect the rhythm of your heart. This includes medicines used for abnormal heart rhythm (antiarrhythmics), for depression (tricyclic antidepressants), for psychiatric disorders (antipsychotics), for bacterial infections or against malaria (e.g. halofantrine).
  • Levothyroxine (thyroid hormone replacement)
  • Ampicillin (antibiotic)
  • Oral typhoid vaccine or rabies vaccine
  • Cyclosporine (immunosuppressant)
  • Mefloquine (used for prevention/ treatment of malaria)
  • Praziquantel (used to treat worm infections)
  • Tamoxifen (used to treat breast cancer)

This is not a complete list of all possible drug interactions with this medication. Check with your healthcare professional if you are unsure.

What else can I do to prevent malaria?

To prevent malaria, you may protect yourself against mosquito bites by:

  • Wearing long-sleeved clothing and long trousers between sunset and sunrise.
  • Applying insect repellent containing more than 20% DEET (N-Diethyl-meta-toluamide) for adults or 10% and less DEET for children on exposed skin. DEET is a common active ingredient in mosquito repellents.
  • Using mosquito coils in the room at night.
  • Sleep with mosquito nets around your bed, with the net edges tucked under the bed or sleep in a screened room.
  • Spray insecticide where mosquitos may rest. Mosquito larvae survive well in clear, slow-flowing streams.
  • Avoid going to an area where malaria is common.

Following these guidelines and medication does not mean that you will not get malaria. If you have a fever or experience chills between 1 week and up to 1 year after your return, you should seek medical attention. Inform the doctor that you have been to a country where malaria is common. Malaria can be effectively treated if discovered early. A delay in treatment may result in serious health problems.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How should I throw away this medication safely?

Pack the medication into a bag and bring it back to the pharmacy where you received the medication from.


Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.


Last reviewed on September 2019

Back to Top