Chloroquine is a medication used to treat acute attacks of malaria caused by Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale. It helps control symptoms and eliminate the parasites that cause the infection.
Chloroquine may also be used with other medications to treat hepatic amebiasis, as well as for rheumatoid arthritis, lupus, and conditions that cause sensitivity to light, such as porphyria cutanea tarda. Its use depends on the condition being treated and should always be directed by a doctor.
Chloroquine is available by prescription in the United States. Although it was studied as a possible treatment for COVID-19, chloroquine is not FDA-approved for this purpose.
What chloroquine is used for
Chloroquine is FDA-approved in the United States for:
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Treatment of uncomplicated malaria caused by susceptible strains of Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax;
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Prevention of malaria in geographic areas where chloroquine resistance is not present;
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Treatment of extraintestinal amebiasis.
Chloroquine is not effective against the liver-stage forms of Plasmodium vivax or Plasmodium ovale and therefore does not prevent relapses of these infections. An additional medication that acts against these forms of the parasite may be needed.
How to take chloroquine
Chloroquine tablets should be taken by mouth with a glass of water after meals to help prevent nausea and vomiting.
The chloroquine dosage varies depending on the condition being treated and may include:
1. Malaria
Chloroquine may be used to treat uncomplicated malaria caused by chloroquine-sensitive strains of Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax.
For Plasmodium vivax and Plasmodium ovale infections, chloroquine does not eliminate the dormant liver-stage parasites that can cause relapse. An additional 8-aminoquinoline medication, such as primaquine, may therefore be prescribed.
The FDA-approved chloroquine dosing schedule for uncomplicated malaria caused by chloroquine-sensitive Plasmodium species is:
The total adult dose is 1,500 mg of chloroquine base over 3 days. For infants and children, the total recommended dose is 25 mg of chloroquine base/kg, and the pediatric dose should never exceed the corresponding adult dose.
For Plasmodium vivax and Plasmodium ovale infections, treatment with an 8-aminoquinoline medication is also necessary to eliminate the dormant liver-stage forms of the parasite.
Chloroquine should not be used to treat complicated malaria or malaria caused by chloroquine-resistant strains. It should also not be used for malaria prevention in areas where chloroquine resistance is present.
2. Extraintestinal amebiasis
Chloroquine is FDA-approved for the treatment of extraintestinal amebiasis.
The recommended dose for adults is 600 mg of chloroquine base per day for the first 2 days of treatment, followed by 300 mg per day for at least 2 to 3 weeks, as directed by a doctor.
The dose and duration of treatment may be adjusted by the doctor depending on the person's response to the medication.
For children, the dose should be calculated according to body weight and prescribed by a pediatrician.
Who should not take chloroquine
Chloroquine should not be used by people who are hypersensitive to chloroquine, other 4-aminoquinoline medications, or any other ingredient in the medication.
Chloroquine should be used with caution in people with psoriasis or porphyria because these conditions may worsen during treatment. Caution is also recommended for people with liver disease or gastrointestinal, neurological, or blood disorders.
Possible side effects
The most common side effects of chloroquine include headache, nausea, vomiting, diarrhea, abdominal pain, itching, skin irritation, and red patches on the skin.
Other possible side effects include confusion, seizures, low blood pressure, changes on an electrocardiogram, and double or blurred vision.
