Chloroquine is a medication to treat or prevent malaria, a disease caused by parasites. This medicine works by interfering with the growth of parasites in the red blood cells of the human body.

Parasites that cause malaria typically enter the body through the bite of a mosquito. Malaria is common in areas such as Africa, South America, and Southern Asia.

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 not listed in this medication guide.

You should not use this medication if you are allergic to chloroquine or hydroxychloroquine (Plaquenil), or if you have a history of vision changes or damage to your retina caused by chloroquine or similar anti-malaria medications.

Before you take chloroquine, tell your doctor if you have psoriasis, porphyria, liver disease, alcoholism, G6PD deficiency, or a history of problems with your vision or hearing.Slideshow: It’s Buggin’ Me! How to Safely Use an Insect Repellent
[It’s Buggin’ Me! How to Safely Use an Insect Repellent]Take chloroquine for the entire length of time prescribed by your doctor. If you are taking this medicineto treatmalaria, your symptoms may get better before the infection is completely treated.

Some people taking this medication over long periods of time or at high doses have developed irreversible damage to the retina of the eye. Stop taking chloroquine and call your doctor at once if you have trouble focusing, if you see light streaks or flashes in your vision, or if you notice any swelling or color changes in your eyes.

This medication may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Call a poison control center at once and then seek emergency medical attention if you think you have used too much of this medicine.An overdose of chloroquine can be fatal, especially in children.

Chloroquine side effects

Some people taking this medication over long periods of time or at high doses have developed irreversible damage to the retina of the eye. Stop taking chloroquine and call your doctor at once if you have trouble focusing, if you see light streaks or flashes in your vision, or if you notice any swelling or color changes in your eyes.

Get emergency medical help if you have any of thesesigns of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using chloroquine and call your doctor at once if you have a serious side effect such as:

vision problems, trouble reading or seeing objects, hazy vision;

hearing loss or ringing in the ears;

seizure (convulsions);

severe muscle weakness, loss of coordination, underactive reflexes;

nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

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

diarrhea, vomiting, stomach cramps;

temporary hair loss, changes in hair color; or

mild muscle weakness.