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Chloroquine (Oral)

Generic name: chloroquine [ KLOR-oh-kwin ]
Brand name: Aralen Phosphate
Drug classes: Amebicides, Antimalarial quinolines

Medically reviewed by Drugs.com. Last updated on May 28, 2023.

Uses for chloroquine

Chloroquine is used to prevent and treat malaria. It is also used to treat liver infection caused by protozoa (extraintestinal amebiasis).

Using this medicine alone or with other medicines (eg, azithromycin) may increase your risk of heart rhythm problems (eg, QT prolongation, ventricular fibrillation, ventricular tachycardia). Do not take any medicine that contains chloroquine unless prescribed by your doctor.

Chloroquine belongs to a group of medicines known as antimalarials. It works by preventing or treating malaria, a red blood cell infection transmitted by the bite of a mosquito. However, this medicine is not used to treat severe or complicated malaria and to prevent malaria in areas or regions where chloroquine is known not to work (resistance).

This medicine is available only with your doctor's prescription.

Before using chloroquine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of chloroquine to prevent and treat malaria in children. However, children are more sensitive to the effects of this medicine than adults. Safety and efficacy of chloroquine to treat extraintestinal amebiasis have not been established in children.

Geriatric

Although appropriate studies on the relationship of age to the effects of chloroquine have not been performed in the geriatric population, geriatric-specific problems are not expected to limit the usefulness of chloroquine in the elderly. However, elderly patients are more likely to have age-related kidney problems, which may require caution and an adjustment in the dose for patients receiving chloroquine.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of chloroquine

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of serious side effects.

For patients taking chloroquine to prevent malaria:

If you are taking this medicine to help keep you from getting malaria, keep taking it for the full time of treatment. If you already have malaria, you should still keep taking this medicine for the full time of treatment even if you begin to feel better after a few days. This will help clear up your infection completely. If you stop taking this medicine too soon, your symptoms may return.

Chloroquine works best when you take it on a regular schedule. For example, if you are taking it once a week to prevent malaria, it is best to take it on the same day of each week. Make sure that you do not miss any doses. If you have any questions about this, check with your doctor.

If you are also taking kaolin or antacids, take them at least 4 hours before or after using chloroquine. If you are also taking ampicillin, take it at least 2 hours before or after using this medicine.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using chloroquine

If you will be taking this medicine for a long time, it is very important that your doctor check your progress at regular visits. This is to make sure that the infection is cleared up completely, and to allow your doctor to check for any unwanted effects. Your doctor may check your blood, urine, eyes, ears, and knee or ankle reflexes during or after using this medicine.

If your symptoms do not improve within a few days, or if they become worse, check with your doctor.

This medicine may cause heart problems and changes in your heart rhythm. Check with your doctor right away if you have chest pain or tightness, decreased urine output, dilated neck veins, extreme fatigue, swelling of the face, fingers, feet, or lower legs, troubled breathing, or weight gain. You may also feel dizzy or faint, or you may have a fast, pounding, or uneven heartbeat.

This medicine may cause hypoglycemia (low blood sugar), which may be life-threatening. Low blood sugar must be treated before it causes you to pass out (unconsciousness). People feel different symptoms of low blood sugar. It is important that you learn which symptoms you usually have so you can treat it quickly. Talk to your doctor about the best way to treat low blood sugar.

Chloroquine may cause vision problems. It may also make you dizzy or lightheaded. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. . If these reactions are especially bothersome, check with your doctor.

Check with your doctor immediately if blurred vision, difficulty with reading, or any other change in vision occurs during or after treatment. Your doctor may want your eyes be checked by an ophthalmologist (eye doctor).

This medicine may cause extrapyramidal disorders (eg, dystonia, dyskinesia, tongue protrusion, torticollis). Check with your doctor right away if you have the following symptoms after using the medicine: difficulty in speaking, drooling, loss of balance control, muscle trembling, jerking, or stiffness, restlessness, shuffling walk, stiffness of the limbs, twisting movements of the body, or uncontrolled movements, especially of the face, neck, and back.

Using this medicine for a long time may cause muscle weakness. Check with your doctor right away if you have muscle weakness while using this medicine.

Children are very sensitive to this medicine, and accidental overdoses have occurred with small amounts of chloroquine. Keep this medicine out of the reach of children.

Check with your doctor right away if you have continuing ringing or buzzing or other unexplained noise in the ears or hearing loss while using this medicine.

While you are being treated with chloroquine, do not have any immunizations (eg, rabies vaccine) without your doctor's approval.

Malaria is spread by the bites of certain kinds of infected female mosquitoes. If you are living in or will be traveling to an area where there is a chance of getting malaria, the following mosquito-control measures will help to prevent infection:

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of chloroquine

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Incidence not known

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

Commonly used brand name(s)

In the U.S.

Available Dosage Forms:

Therapeutic Class: Antimalarial

Chemical Class: Aminoquinoline

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.