Examples

You take chloroquine as a tablet (orally).

How It Works

Chloroquine prevents the development of malaria parasites in the blood. Doctors use it to both prevent and treat malaria. Chloroquine does not destroy the Plasmodium (P.)vivax and P. ovale parasites that may remain in the liver.

To prevent some strains of malaria, you take chloroquine once, 1 to 2 weeks prior to travel to an area where malaria is present, and then weekly while you are in the area, and weekly for 4 weeks after you depart from the area.

To treat malaria, you take chloroquine at several-hour intervals and at a higher dosage than when it's taken to prevent malaria.

Why It Is Used

Chloroquine is the medicine of choice to prevent and treat malaria in some areas of the world.

Chloroquine is effective on all five species of parasites, including some strains of P. falciparum. But in many areas P. falciparum is resistant to chloroquine, and other medicines must be used.

Chloroquine can also be used to prevent and treat P. falciparum and P. vivax infections in areas where drug resistance to chloroquine has not been confirmed. These areas include Central America, the Caribbean, and parts of the Middle East. ¹ Other parts of the world have confirmed resistance to chloroquine.

How Well It Works

Chloroquine is an effective medicine to prevent and treat a malaria infection caused by P. ovale or P. malariae parasites. But how well it works depends on how resistant the parasites are in the geographic location where the malaria infection occurred.

Medication therapy to prevent malaria is most effective if you take the correct dosage regularly. It's easier to remember if you take your weekly dosage with meals on the same day of the week each week, such as every Monday at lunch.

Side Effects

When you take chloroquine to prevent malaria, side effects may include:

• Nausea.
• Diarrhea.
• Dizziness.
• Sleep disturbances.
• Headaches.
• Temporary hair loss.
• Worsening of psoriasis, a chronic skin condition.

Taking the medicine with meals may help you to avoid stomach upset.

When you take chloroquine to treat malaria, side effects may include:

• Stomach (gastrointestinal) upset.
• Blurred vision or seeing flashes of light.
• Headaches.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Chloroquine is the most effective medication for preventing and treating a malaria infection caused by P. ovale, P. malariae, or P. knowlesi parasites.

In some areas where malaria is common, travelers are sometimes advised to get a rabies vaccine if they are staying longer than 30 days. If you are taking chloroquine, make sure the rabies vaccine is injected into your muscle (intramuscular). Chloroquine can lessen the effectiveness of this vaccine when it is injected into the skin (intradermal).

Medicines to prevent malaria destroy the malaria parasite once it enters the bloodstream. To completely rid yourself of the parasite, take the medicine for 4 weeks after you leave the area where malaria is present.

If you are pregnant or have other medical considerations (very young or advanced age, other illnesses), talk to your doctor before taking chloroquine.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

Citations

1. Centers for Disease Control and Prevention (2008). Yellow Book 2008. Available online: wwwn.cdc.gov/travel/ybtoc.aspx.