Chloroquine

  • Brand Name : Aralen
  • Drug Class : Antimalarials
  • Medical Author : Sarfaroj Khan, BHMS, PGD Health Operations
  • Medical Reviewer :
  • _eael_post_view_count : 10

What Is Chloroquine and How Does It Work?

Chloroquine is a prescription medication used to treat the symptoms of Malaria and Extraintestinal Amebiasis.  

  • Chloroquine is available under the following different brand names: Chloroquine phosphate

What Are Dosages of Chloroquine?

Adult and Pediatric dosage

Tablet

  • 500mg

Note: Chloroquine phosphate 16.6 mg is equivalent to 10 mg chloroquine base

Malaria

Adult dosage

Prophylaxis

  • 500 mg (300-mg base) weekly on the same day each week; begin 1-2 weeks before travel, during travel, and for 4 weeks after leaving the endemic area. 

Pediatric Dosage

  • 5 mg/kg orally once per week, not to exceed 500 mg (300-mg base), on the same day each week; begin 1-2 weeks before travel, during travel, and for 4 weeks after leaving the endemic area.

Treatment

Acute Attack

  • 1 g (600-mg base) orally, then
  • 500 mg (300-mg base) orally after 6-8 hours, then
  • 500 mg (300-mg base) orally at 24 hour and 48 hours after initially dose
  • Total dose of 2500 mg (1500 mg-base) in 3 days

Pediatric dosage

  • First dose: 10 mg base/kg (not to exceed 600-mg base/dose)
  • Second dose: (6 hours after first dose) 5 mg base/kg (not to exceed 300 mg base/dose)
  • Third dose: (24 hours after first dose) 5 mg base/kg (not to exceed 300 mg base/dose)
  • Fourth dose: (36 hours after first dose) 5 mg base/kg (not to exceed 300 mg base/dose)
  • Total dose 25 mg base/kg

Amebiasis, Extraintestinal

  • 1 g (600 mg base) orally once daily for 2 days, then 
  • 500 mg (300 mg base) once daily for 14-21 days

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages.”

What Are Side Effects Associated with Using Chloroquine?

Common side effects of Chloroquine include:

  • nausea, 
  • vomiting, 
  • diarrhea, 
  • stomach cramps
  • headache, 
  • unusual changes in mood or behavior, 
  • hair loss, and 
  • changes in hair or skin color

Serious side effects of Chloroquine include:

  • hives, 
  • difficulty breathing, 
  • swelling of the face, lips, tongue, or throat, 
  • fever,
  • sore throat
  • burning eyes, 
  • skin pain, 
  • red or purple skin rash with blistering and peeling, 
  • fast or pounding heartbeats, 
  • fluttering in the chest, 
  • shortness of breath, 
  • sudden dizziness, 
  • seizure
  • ringing in ears, 
  • trouble hearing, 
  • severe muscle weakness, 
  • loss of coordination, 
  • underactive reflexes, 
  • chills, 
  • tiredness, 
  • mouth sores, 
  • skin sores, 
  • easy bruising, 
  • unusual bleeding, 
  • pale skin, 
  • cold hands and feet, 
  • shortness of breath, 
  • lightheadedness
  • headache, 
  • hunger, 
  • sweating, 
  • irritability, 
  • anxiety, 
  • shakiness, 
  • skin rash, 
  • swollen glands, 
  • muscle aches, 
  • severe weakness, 
  • yellowing of the skin or eyes (jaundice), 
  • blurred vision, 
  • trouble focusing, 
  • trouble reading, 
  • distorted vision, 
  • poor night vision, 
  • changes in color vision, 
  • hazy or cloudy vision, 
  • seeing light flashes or steaks, 
  • seeing halos around lights, and
  • increased sensitivity to light

Rare side effects of Chloroquine include:

  • none 

This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Chloroquine?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first

  • Chloroquine has severe interactions with at least 11 other drugs.
  • Chloroquine has serious interactions with at least 79 other drugs.
  • Chloroquine has moderate interactions with at least 140 other drugs.
  • Chloroquine has minor interactions with at least 99 other drugs. 

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drugs interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use.  Keep a list of all your medications with you, and share this information with your doctor and pharmacist.  Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Chloroquine?

Contraindications

Effects of drug abuse

  • None

Short-Term Effects

  • See “What are Side Effects Associated with Using Chloroquine?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Chloroquine?”

Cautions

  • Acute extrapyramidal disorders may occur; reactions usually resolve after treatment discontinuation and/or symptomatic treatment
  • Not effective in most areas; CDC recommends mefloquine or atovaquone/proguanil – check CDC traveler information for specific recommendations for region
  • May cause hemolysis in glucose-6 phosphate dehydrogenase (G-6-PD) deficiency; blood monitoring may be needed as hemolytic anemia may occur, in particular in association with other drugs that cause hemolysis
  • Experimental data showed a potential risk of inducing gene mutations; there are insufficient data in humans to rule out an increased risk of cancer in patients receiving long-term treatment
  • Cases of cardiomyopathy resulting in cardiac failure, in some cases with fatal outcome, have been reported in patients treated during long term therapy at high doses with chloroquine; monitor for signs and symptoms of cardiomyopathy and discontinue chloroquine if cardiomyopathy develops
  • May cause conduction disorders (eg, bundle branch block / AV heart block) are diagnosed; if cardiotoxicity is suspected, prompt discontinuation of chloroquine may prevent life-threatening complications
  • Monitor knee and ankle reflexes in patients on long-term therapy to detect any evidence of muscular weakness; if weakness occurs, discontinue therapy
  • A number of fatalities have been reported following the accidental ingestion of chloroquine; advise to keep medication out of the reach of children because they are especially sensitive to the 4-aminoquinoline compounds
  • Use in patients with psoriasis may precipitate a severe attack of psoriasis; may be exacerbated condition when used in patients with porphyria; do not use in these conditions unless the benefit to the patient outweighs the potential risks
  • Shown to cause severe hypoglycemia including loss of consciousness that could be life-threatening in patients treated with or without antidiabetic medications; patients should be warned about risk of hypoglycemia and associated clinical signs and symptoms; patients presenting with clinical symptoms suggestive of hypoglycemia during treatment with chloroquine should have blood glucose level checked and treatment reviewed as necessary
  • Caution with history of auditory damage
  • Caution with hepatic disease, alcoholism, and coadministration with other hepatotoxic drugs
  • May provoke seizures in patients with history of epilepsy
  • QT prolongation
  • QT interval prolongation, torsade de pointes, and ventricular arrhythmias have been reported
  • The risk increases with higher doses chloroquine; fatal cases have been reported
  • Use with caution in patients with cardiac disease, a history of ventricular arrhythmias, uncorrected hypokalemia and/or hypomagnesemia, or bradycardia (less than 50 bpm)
  • Retinopathy
  • Irreversible retinal damage observed
  • Significant risk factors for retinal damage include daily doses of chloroquine phosphate >2.3 mg/kg of actual body weight, durations of use >5 years, subnormal glomerular filtration, and concurrent macular disease
  • Perform baseline ophthalmological examination within the first year of starting chloroquine phosphate tablets
  • Baseline exam should include: best corrected distance visual acuity (BCVA), an automated threshold visual field (VF) of the central 10 degrees (with retesting if an abnormality is noted), and spectral domain optical coherence tomography (SD-OCT)
  • Exams (including BCVA, VF and SD-OCT) should be monitored annually in individuals with significant risk factors and may be deferred up to 5 years for individuals without risk factors
  • In patients of Asian descent, it is recommended that visual field testing be performed in the central 24 degrees instead of the central 10 degrees
  • Discontinue if ocular toxicity is suspected and closely monitor; retinal changes (and visual disturbances) may progress even after cessation of therapy
  • Drug interaction overview
    • Plasma concentrations of chloroquine and desethylchloroquine (major metabolite of chloroquine) were negatively associated with log antibody titers; the recommended dose of chloroquine for malaria prophylaxis can reduce the antibody response to primary immunization with intradermal human diploid-cell rabies vaccine
    • Concomitant use of chloroquine with drugs known to induce retinal toxicity such as tamoxifen is not recommended
  • Effects of other drugs on chloroquine
    • Antacids and kaolin can reduce absorption of chloroquine; observe for at least 4 hr between intake of these agents and chloroquine
    • Cimetidine can inhibit the metabolism of chloroquine, increasing its plasma level; avoid use
  • Chloroquine effects on other drugs
    • As chloroquine may enhance the effects of a hypoglycemic treatment, a decrease in doses of insulin or other antidiabetic drugs may be required.
    • Chloroquine significantly reduced the bioavailability of ampicillin; monitor at least 2 hr between intake of ampicillin and chloroquine
    • After the introduction of chloroquine (oral form), a sudden increase in serum cyclosporine level has been reported; closely monitor of serum cyclosporine level and if necessary, discontinue chloroquine
  • May increase risk of inducing ventricular arrhythmias if chloroquine is used concomitantly with other arrhythmogenic drugs (eg, amiodarone, moxifloxacin)
  • In a single-dose interaction study, chloroquine has been reported to reduce the bioavailability of praziquantel
  • Coadministration of chloroquine and mefloquine may increase the risk of convulsions

Pregnancy and Lactation

  • In humans, at recommended doses for prophylaxis and treatment of malaria, observational studies as well as a meta-analysis, including a small number of prospective studies with chloroquine exposure during pregnancy, have shown no increase in the rate of birth defects or spontaneous abortions
  • Avoid use during pregnancy except in prophylaxis or treatment of malaria when benefit outweighs potential risk to the fetus.
  • Owing to the potential for serious adverse reactions in nursing infants from chloroquine, a decision should be made whether to discontinue nursing or chloroquine, taking into account the potential clinical benefit of the drug to the mother
  • Excretion of chloroquine and the major metabolite, desethylchloroquine, in breast milk was investigated in eleven lactating mothers following a single oral dose of chloroquine (600-mg base); maximum daily dose of the drug that the infant can receive from breastfeeding was about 0.7% of the maternal start dose of the drug in malaria
  • Separate prophylaxis for the infant is required.

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