Chloroquine (By mouth)


Chloroquine (KLOR-oh-kwin)

Prevents and treats malaria. Also treats the liver infection extraintestinal amebiasis.

Brand Name(s)

Aralen Phosphate

When This Medicine Should Not Be Used

How to Use This Medicine


  • Take your medicine as directed. If you take this medicine only once a week, always take it on the same day of each week.
  • Malaria prevention while traveling: You may need to start using this medicine 2 weeks before you start your trip. You may also need to keep using this medicine for 8 weeks after you get home. Ask your doctor about your schedule.
  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.
  • Missed dose:
    • If you take your medicine once every 7 days, take the missed dose as soon as you can, then wait 7 days before taking another dose.
    • If you take your medicine every day, take the missed dose as soon as you can. If it is almost time for your next regular dose, wait until then to take your medicine and skip the missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some foods and medicines can affect how chloroquine works. Tell your doctor if you are using cimetidine, cyclosporine, or mefloquine, or if you need a rabies vaccine.
  • Antacid or kaolin: Take at least 4 hours before or after chloroquine.
  • Ampicillin: Take at least 2 hours before or after chloroquine.

Warnings While Using This Medicine

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, porphyria, psoriasis, hearing problems, G6PD deficiency, or a history of epilepsy. Tell your doctor if you drink alcohol.
  • Tell your doctor if you have had eye or vision problems caused by chloroquine or similar drugs.
  • This medicine may cause the following problems:
    • Changes in vision, eye damage
    • Extrapyramidal disorders, muscle weakness
  • Call your doctor if your symptoms do not improve or if they get worse.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments. Your may need to have your eyes, ears, and reflexes tested.
  • Children are very sensitive to this medicine. Accidental overdoses have occurred with small amounts of chloroquine.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Changes in vision, trouble seeing, light flashes
  • Trouble hearing, ringing in the ears
  • Twitching or muscle movements you cannot control, problems with balance or walking, muscle weakness
  • Unusual bleeding, bruising, or weakness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 7/4/2015

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