What is chloroquine?

Chloroquine is an antimalarial drug. The exact way that chloroquine works is unknown.

Chloroquine is used to treat and to prevent malaria. Chloroquine is also used to treat infections caused by amoebae.

Chloroquine may also be used for purposes other than those listed in this medication guide.


Before taking this medication, tell your doctor if you have

  • had a previous allergic reaction to chloroquine;
  • glucose-6-phosphate dehydrogenase (G-6-PD) deficiency;
  • psoriasis;
  • porphyria; or
  • liver disease.

You may not be able to take chloroquine, or you may require a dosage adjustment or special monitoring during your therapy if you have any of the conditions listed above.

It is not known whether chloroquine will be harmful to an unborn baby. Do not take chloroquine without first talking to your doctor if you are pregnant or could become pregnant during treatment.

It is not known how chloroquine will affect a nursing infant. Do not take chloroquine without first talking to your doctor if you are breast-feeding a baby.

Use caution when driving or performing other hazardous activities until you know how this medication affects you. Chloroquine may cause visual disturbances such as blurred vision, misty vision, and difficulty focusing. Report any vision or hearing changes to your doctor.

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Seek emergency medical attention if an overdose is suspected.

Symptoms of a chloroquine overdose include headache, drowsiness, nausea, vomiting, visual changes, seizures, difficulty breathing, and unconsciousness.

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and only take the next regularly scheduled dose. Do not take a double dose of this medication.

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Side effects

Stop taking chloroquine and seek emergency medical attention if you experience an allergic reaction (flushing; swelling of the lips, tongue, or face; difficulty breathing; closing of the throat; vision problems; rash; itching; or fever).

Other, less serious side effects may be more likely to occur. Continue to take chloroquine and talk to your doctor if you experience

  • visual disturbances such as blurred vision, misty vision, and difficulty focusing;
  • hearing loss or ringing in the ears;
  • diarrhea, nausea, stomach pain or upset, vomiting, or loss of appetite;
  • muscle weakness; or
  • a rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may report side effects to FDA at 1-800-FDA-1088.

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Cimetidine (Tagamet, Tagamet HB) may increase the effects of chloroquine, which could lead to toxicity. Do not take cimetidine without first talking to your doctor.

Kaolin and magnesium trisilicate may decrease the effects of chloroquine. These ingredients can be found in products such as Kaopectate Advanced Formula, Parepectolin, K-Pek, K-C, Kaodene Non-Narcotic, Kao-Spen, Gaviscon, and others.

Drugs other than those listed here may also interact with chloroquine. Do not take any other prescription or over-the-counter medicines, including vitamins, minerals, and herbal products, without first talking to your doctor.

Other Names

Aralen Hydrochloride, Aralen Phosphate, and chloroquine

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