Chloroquine

Generic name: chloroquine
Brand names: Aralen Phosphate, Aralen Hydrochloride
Dosage form: oral tablet (250 mg; 500 mg)
Drug classes: Amebicides, Antimalarial quinolines

Medically reviewed by  A Ras MD.

What is chloroquine?

Chloroquine is used to treat or prevent malaria. It is used to treat a type of bowel infection. Chloroquine may be given to you for other reasons.

Description

Chloroquine phosphate, USP, is a 4-aminoquinoline compound for oral administration. It is a white, odorless, bitter tasting, crystalline substance, freely soluble in water.

Chemically, it is 7-chloro-4-[[4-(diethylamino)-1-methylbutyl]amino] quinoline phosphate (1:2) and has the following structural formula:

Each tablet contains 500 mg of chloroquine phosphate USP, equivalent to 300 mg chloroquine base.

Inactive Ingredients: Carnauba Wax, Colloidal Silicon Dioxide, Dibasic Calcium Phosphate, Hydroxypropyl Methylcellulose, Magnesium Stearate, Microcrystalline Cellulose, Polyethylene Glycol, Polysorbate 80, Pregelatinized Starch, Sodium Starch Glycolate, Stearic Acid, Titanium Dioxide.

Before taking chloroquine, tell your doctor:

• If you are allergic to chloroquine; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
• If you have ever had any eye changes or changes in eyesight.
• If you have psoriasis.
• If you have porphyria.
• If you are taking cimetidine.
• If you are taking tamoxifen.
• If you are breast-feeding or plan to breast-feed.

This is not a list of all drugs or health problems that interact with chloroquine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take chloroquine with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take chloroquine?

For all uses of chloroquine:

• Tell all of your health care providers that you take chloroquine. This includes your doctors, nurses, pharmacists, and dentists.
• A severe eye problem has happened with chloroquine. This may lead to lasting eyesight problems. The risk may be higher if you have some types of eye or kidney problems. The risk may also be higher with some doses of chloroquine, if you use chloroquine for longer than 5 years, or if you take certain other drugs like tamoxifen. Call your doctor right away if you have any eyesight changes like blurred or foggy eyesight, trouble focusing or reading, or trouble seeing in dim light. Call your doctor right away if you lose part of your eyesight, if you see dark spots, or if you see only part of an object.
• Have an eye exam as you have been told by your doctor.
• Be careful if you have G6PD deficiency. Anemia may happen.
• Have your blood work checked if you are on chloroquine for a long time. Talk with your doctor.
• Talk with your doctor before you drink alcohol.
• Some other drugs may need to be taken at some other time than chloroquine. If you take other drugs, check with your doctor or pharmacist to see if you need to take them at some other time than chloroquine.
• This medicine may make you sunburn more easily. Use care if you will be in the sun. Tell your doctor if you sunburn easily while taking chloroquine.
• Low blood sugar has happened with chloroquine. Sometimes, this has been very bad and could be life-threatening. Talk with the doctor.
• Check your blood sugar as you have been told by your doctor.
• A severe and sometimes deadly reaction has happened. Most of the time, this reaction has signs like fever, rash, or swollen glands with problems in body organs like the liver, kidney, blood, heart, muscles and joints, or lungs. If you have questions, talk with the doctor.
• This medicine may add to the chance of getting some types of cancer. Talk with the doctor.
• Keep away from children. Accidental exposure may cause death. If a child takes chloroquine by accident, get medical help right away.
• If you are 65 or older, use chloroquine with care. You could have more side effects.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using chloroquine while you are pregnant.

Preventing malaria:

• Other measures are needed along with chloroquine including using screens, bed netting, insect repellent (10% to 35% DEET), and permethrin spray on clothing and nets. Avoid spraying most insect repellents on children. Lower evening and night-time outdoor activity.
• If you are a pregnant woman and traveling to a malaria infested place, talk to your doctor about the risks first.

How is chloroquine best taken?

Use chloroquine as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Take with or without food. Take with food if it causes an upset stomach.
• Be sure you know how to take chloroquine. Talk with your doctor if you have questions.
• Keep taking chloroquine as you have been told by your doctor or other health care provider, even if you feel well.
• Do not take antacids or kaolin within 4 hours of chloroquine.

What do I do if I miss a dose?

• Take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.

What are the side effects of chloroquine that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

For all uses of chloroquine:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
• Signs of low blood sugar like dizziness, headache, feeling sleepy, feeling weak, shaking, a fast heartbeat, confusion, hunger, or sweating.
• Trouble controlling body movements.
• Restlessness.
• Seizures.
• Mood changes.
• Change in how you act.
• Not able to sleep.
• Feeling confused.
• Hallucinations (seeing or hearing things that are not there).
• Change in hearing.
• Ringing in ears.
• Muscle pain or weakness.
• A burning, numbness, or tingling feeling that is not normal.
• Fever or chills.
• Sore throat.
• Any unexplained bruising or bleeding.
• Feeling very tired or weak.
• A very bad skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause very bad health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
• Heart problems like heart failure and abnormal heartbeats have happened in people taking high doses of chloroquine for a long time. Sometimes, these have been deadly. Call your doctor right away if you have a fast or abnormal heartbeat; very bad dizziness or passing out; or shortness of breath, a big weight gain, or swelling in the arms or legs.

Preventing malaria:

• Fever that happens while in or after coming back from the malaria area.

What are some other side effects of chloroquine?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Belly pain.
• Stomach cramps.
• Not hungry.
• Upset stomach or throwing up.
• Headache.
• Diarrhea.
• Change in color of skin.
• Change in color of hair.
• Hair loss.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out chloroquine?

• Store at room temperature.
• Store in a dry place. Do not store in a bathroom.
• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

SRC: NLM .