Chloroquine

(klor' oh kwin)

Brand Name(s): Aralen^®¶; also available generically

IMPORTANT NOTICE:

Chloroquine has been studied for the treatment and prevention of coronavirus disease 2019 (COVID-19).

The FDA had approved an Emergency Use Authorization (EUA) on March 28, 2020 to allow distribution of chloroquine for the treatment adults and adolescents who weigh at least 110 pounds (50 kg) and who are hospitalized with COVID-19, but who are unable to participate in a clinical study. However, FDA canceled this on June 15, 2020 because clinical studies showed that chloroquine is unlikely to be effective for treatment of COVID-19 in these patients and some serious side effects, such as irregular heartbeat were reported.

The FDA and the National Institutes of Health (NIH) state that chloroquine should ONLY be taken for the treatment of COVID-19 under the direction of a doctor in a clinical study. Do not buy this medication online without a prescription. If you experience irregular heartbeats, dizziness, or fainting while taking chloroquine, call 911 for emergency medical treatment. If you have other side effects, be sure to tell your doctor.

Do not take chloroquine that is strictly intended for veterinary use – such as to treat fish in aquariums or for use in other animals – to treat or prevent COVID-19. The FDA reports that serious injury and death have been reported in people misusing these preparations. https://bit.ly/2KpIMcR

WHY is this medicine prescribed?

Chloroquine phosphate is used to prevent and treat malaria. It is also used to treat amebiasis. Chloroquine phosphate is in a class of drugs called antimalarials and amebicides. It works by killing the organisms that cause malaria and amebiasis.

Are there OTHER USES for this medicine?

Chloroquine phosphate is used occasionally to decrease the symptoms of rheumatoid arthritis and to treat systemic and discoid lupus erythematosus, sarcoidosis, and porphyria cutanea tarda. Talk to your doctor about the possible risks of using this drug for your condition.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Chloroquine phosphate comes as a tablet to take by mouth. For prevention of malaria in adults, one dose is usually taken once a week on exactly the same day of the week. Your doctor will tell you how many tablets to take for each dose. One dose is taken beginning 2 weeks before traveling to an area where malaria is common, while you are in the area, and then for 8 weeks after you return from the area. If you are unable to start taking chloroquine for 2 weeks before traveling, your doctor may tell you to take double the dose right away (for the first dose).

For treatment of sudden, severe attacks of malaria in adults, one dose is usually taken right away, followed by half the dose 6 to 8 hours later and then half the dose once a day for the next 2 days.

For prevention and treatment of malaria in infants and children, the amount of chloroquine phosphate is based on the child's weight. Your doctor will calculate this amount and tell you how much chloroquine phosphate your child should receive.

For treatment of amebiasis, one dose is usually taken for 2 days and then half the dose every day for 2 to 3 weeks. It is usually taken in combination with other amebicides.

Chloroquine phosphate may cause an upset stomach. Take chloroquine phosphate with food.

Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use chloroquine phosphate exactly as directed. Do not use more or less of it or use it more often than prescribed by your doctor.

What SPECIAL PRECAUTIONS should I follow?

Before using chloroquine phosphate,

• tell your doctor and pharmacist if you are allergic to chloroquine phosphate, chloroquine hydrochloride, hydroxychloroquine (Plaquenil), or any other drugs.

• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention acetaminophen (Tylenol, others); azithromycin (Zithromax); cimetidine (Tagamet); cyclosporine (Gengraf, Neoral, Sandimmune); insulin and oral medications for diabetes; medications for seizures such as carbamazepine (Carbatrol, Epitol, Equetro, Tegretol, Teril), phenytoin (Dilantin, Phenytek), or valproic acid (Depakene); certain medications for irregular heartbeat such as amiodarone (Pacerone); methotrexate (Trexall, Xatmep); moxifloxacin (Avelox); praziquantel (Biltricide); and tamoxifen (Nolvadex). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with chloroquine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.

• if you are taking antacids, take them 4 hours before or 4 hours after chloroquine. If you are taking ampicillin, take it at least 2 hours before or 2 hours after chloroquine.

• tell your doctor if you have or have ever had liver disease, heart disease, a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death), an irregular heartbeat, a low level of magnesium or potassium in your blood, G-6-PD deficiency (an inherited blood disease), hearing problems, porphyria or other blood disorders, psoriasis, seizures, vision problems, diabetes, weakness in your knees and ankles, or if you drink large amounts of alcohol.

• tell your doctor if you have ever had vision changes while taking chloroquine phosphate, chloroquine hydrochloride, or hydroxychloroquine (Plaquenil).

• tell your doctor if you are pregnant or plan to become pregnant. If you become pregnant while using chloroquine phosphate, call your doctor.

• tell your doctor if you are breastfeeding or plan to breastfeed. Chloroquine phosphate can harm a nursing infant.

• do not have any vaccinations without talking to your doctor.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor instructs you otherwise, continue your normal diet while taking chloroquine phosphate.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Side effects from chloroquine phosphate can occur. Tell your doctor if any of these symptoms are severe or do not go away:

• headache
• nausea
• loss of appetite
• diarrhea
• upset stomach
• stomach pain
• rash
• itching
• hair loss

If you experience any of the following symptoms, call your doctor immediately:

• seeing light flashes and streaks
• blurred vision
• reading or seeing difficulties (words disappear, seeing half an object, misty or foggy vision)
• difficulty hearing
• ringing in ears
• muscle weakness
• drowsiness
• vomiting
• irregular heartbeats
• convulsions
• difficulty breathing
• mood or mental changes
• decreased consciousness or loss of counsciousness
• thinking about harming or killing yourself

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light and excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• nausea
• vomiting
• headache
• drowsiness
• visual disturbances
• convulsions
• irregular heartbeat

What OTHER INFORMATION should I know?

Children are especially sensitive to an overdose, so keep the medication out of the reach of children.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests and electrocardiograms (EKG, a test to monitor your heart rate and rhythm) to check your response to chloroquine phosphate. Your doctor will also test your reflexes to see if you have muscle weakness that may be caused by the drug.

If you are taking chloroquine phosphate for a long period of time, your doctor will recommend frequent eye exams. It is very important that you keep these appointments. Chloroquine phosphate can cause serious vision problems. If you experience any changes in vision, stop taking chloroquine phosphate and call your doctor immediately.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

^¶ This branded product is no longer on the market. Generic alternatives may be available.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: October 15, 2020.