Name: Aralen

Aralen Dosage and Administration


Administer orally.136

Oral Administration

Administration with a meal may minimize adverse GI effects.121 134

For prevention of malaria, give once weekly on same day each week.136


Available as chloroquine phosphate;136 dosage usually expressed in terms of chloroquine.136

Each 500-mg tablet of chloroquine phosphate contains 300 mg of chloroquine.136

Dosage in children is based on body weight.136

Pediatric Patients

Malaria Prevention of Malaria in Areas without Chloroquine-resistant Plasmodium Oral

5 mg/kg (8.3 mg/kg of chloroquine phosphate) once weekly on same day each week.115 134 136

Initiate prophylaxis 1–2 weeks prior to entering malarious area and continue during stay and for 4 weeks after leaving the area.115

If exposure occurred in areas where P. ovale or P. vivax is endemic, terminal prophylaxis with a 14-day regimen of primaquine may be indicated;115 136 give during final 2 weeks of chloroquine prophylaxis or, if not feasible, give after chloroquine prophylaxis discontinued.115

Treatment of Uncomplicated Chloroquine-susceptible Malaria Oral

Initial dose of 10 mg/kg of chloroquine (16.7 mg/kg of chloroquine phosphate) followed by 5 mg/kg (8.3 mg/kg of chloroquine phosphate) given at 6, 24, and 48 hours after initial dose.134 144


Malaria Prevention of Malaria in Areas without Chloroquine-resistant Plasmodium Oral

300 mg (500 mg of chloroquine phosphate) once weekly on same day each week.134 115 136

Initiate prophylaxis 1–2 weeks prior to entering malarious area and continue during and for 4 weeks after leaving the area.115

If exposure occurred in areas where P. ovale or P. vivax is endemic, terminal prophylaxis with a 14-day regimen of primaquine may be indicated;115 136 give during final 2 weeks of chloroquine prophylaxis or, if not feasible, give after chloroquine prophylaxis discontinued.115

Treatment of Uncomplicated Chloroquine-susceptible Malaria Oral

Initial dose of 600 mg of chloroquine (1 g of chloroquine phosphate) followed by 300 mg (500 mg of chloroquine phosphate) given at 6, 24, and 48 hours after initial dose.134 144

Prophylaxis of P. ovale or P. vivax When Primaquine Deferred during Pregnancy Oral

300 mg (500 mg of chloroquine phosphate) once weekly for duration of the pregnancy.143 144 Give after usual treatment regimen and continue until a 14-day regimen of primaquine can be given after delivery to provide a radical cure.143 144

Extraintestinal Amebiasis Oral

600 mg of chloroquine (1 g of chloroquine phosphate) once daily for 2 days, followed by 300 mg (500 mg of chloroquine phosphate) once daily for at least 2–3 weeks; usually used in conjunction with an intestinal amebicide.136

Rheumatoid Arthritis† Oral

150 mg (250 mg of chloroquine phosphate) daily.a Reduce dosage after remission or maximum improvement occurs.a

Response may not occur until after >4–6 weeks of therapy.a Some clinicians recommend the drug be continued for 4 months before being considered ineffective for treatment of rheumatoid arthritis.a

Lupus Erythematosus† Oral

150 mg (250 mg of chloroquine phosphate) daily.a

When used in conjunction with topical corticosteroids in treatment of discoid lupus erythematosus, skin lesions may regress within 3–4 weeks and new lesions may not appear.a When systemic and cutaneous manifestations of lupus erythematosus subside, reduce chloroquine dosage gradually over several months, and discontinue as soon as possible.a

Prescribing Limits

Pediatric Patients

Malaria Prevention of Malaria in Areas Without Chloroquine-resistant Plasmodium Oral

Maximum dose 300 mg (500 mg of chloroquine phosphate).115 134 136

Treatment of Uncomplicated Chloroquine-susceptible Malaria Oral

Maximum dose 600 mg (1 g of chloroquine phosphate).134


Malaria Treatment of Uncomplicated Chloroquine-susceptible Malaria Oral

Maximum initial dose 600 mg (1 g of chloroquine phosphate); maximum subsequent doses 300 mg (500 mg of chloroquine phosphate).136

Special Populations

Hepatic Impairment

No specific recommendations available regarding need for dosage adjustment in individuals with hepatic impairment;136 use with caution.136 (See Hepatic Impairment under Cautions.)

Renal Impairment

No specific recommendations available regarding need for dosage adjustment in individuals with renal impairment;136 substantially eliminated by the kidneys.136 (See Renal Impairment under Cautions.)

Geriatric Patients

Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.136

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about Aralen, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • 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.

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about Aralen. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using Aralen (chloroquine).

Review Date: October 4, 2017



Chloroquine is very rapidly and completely absorbed after ingestion. Toxic doses of chloroquine can be fatal. As little as 1 g may be fatal in children. Toxic symptoms can occur within minutes. These consist of headache, drowsiness, visual disturbances, nausea and vomiting, cardiovascular collapse, shock and convulsions followed by sudden and early respiratory and cardiac arrest. Hypokalemia has been observed with arrhythmias in cases of intoxication. The electrocardiogram may reveal atrial standstill, nodal rhythm, prolonged intraventricular conduction time, and progressive bradycardia leading to ventricular fibrillation and/or arrest.


Treatment is symptomatic and must be prompt with immediate evacuation of the stomach by emesis (at home, before transportation to the hospital) or gastric lavage until the stomach is completely emptied. If finely powdered, activated charcoal is introduced by stomach tube, after lavage, and within 30 minutes after ingestion of the antimalarial, it may inhibit further intestinal absorption of the drug. To be effective, the dose of activated charcoal should be at least five times the estimated dose of chloroquine ingested.

Convulsions, if present, should be controlled before attempting gastric lavage. If due to cerebral stimulation, cautious administration of an ultra short-acting barbiturate may be tried but, if due to anoxia, it should be corrected by oxygen administration and artificial respiration. Monitor ECG. In shock with hypotension, a potent vasopressor should be administered. Replace fluids and electrolytes as needed. Cardiac compressing or pacing may be indicated to sustain the circulation. Because of the importance of supporting respiration, tracheal intubation or tracheostomy, followed by gastric lavage, may also be necessary. Peritoneal dialysis and exchange transfusions have also been suggested to reduce the level of the drug in the blood.

Intervention options can involve: diazepam for life-threatening symptoms, seizures and sedation, epinephrine for treatment of vasodilation and myocardial depression, potassium replacement with close monitoring of serum potassium levels.

A patient who survives the acute phase and is asymptomatic should be closely observed for at least six hours. Fluids may be forced, and sufficient ammonium chloride (8 g daily in divided doses for adults) may be administered for a few days to acidify the urine to help promote urinary excretion in cases of both overdosage or sensitivity.

How is Aralen Supplied

Tablets containing 500 mg chloroquine phosphate USP, equivalent to 300 mg of chloroquine base, bottles of 25 (NDC 0024-0084-01).

White, film-coated convex, discoid tablet, 1/2 inch in diameter with an uncoated core, printed in black ink with a stylized "W" on one side and an "A77" on the other side.

Dispense in tight, light-resistant container as defined in the USP/NF.

Store at 25° C (77° F); excursions permitted to 15° – 30° C (59° – 86° F) [see USP Controlled Room Temperature]

What should i avoid while taking chloroquine (aralen phosphate)?

Avoid taking an antacid or Kaopectate (kaolin-pectin) within 4 hours before or after you take chloroquine. Some antacids can make it harder for your body to absorb chloroquine.

If you also take an antibiotic called ampicillin (Principen, Unasyn), avoid taking it within 2 hours before or after you take chloroquine. Chloroquine can make ampicillin much less effective when taken at the same time.

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.

For the Consumer

Applies to chloroquine: oral tablet

Along with its needed effects, chloroquine (the active ingredient contained in Aralen) 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 while taking chloroquine:

Incidence not known
  • Anxiety
  • attempts at killing oneself
  • back, leg, or stomach pains
  • black, tarry stools
  • bleeding gums
  • blistering, peeling, or loosening of the skin
  • blood in the urine or stools
  • blurred or decreased vision
  • change in near or distance vision
  • chest discomfort or pain
  • chills
  • cold sweats
  • confusion
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cough
  • dark urine
  • diarrhea
  • difficulty in focusing the eyes
  • difficulty with speaking
  • difficulty with swallowing
  • disturbed color perception
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • double vision
  • drooling
  • fast, slow, irregular, or pounding heartbeat
  • feeling that others are watching you or controlling your behavior
  • feeling that others can hear your thoughts
  • feeling, seeing, or hearing things that are not there
  • fever
  • general tiredness and weakness
  • halos around lights
  • headache
  • hearing loss
  • inability to move the eyes
  • increased blinking or spasms of the eyelid
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • loss of balance control
  • lower back or side pain
  • muscle trembling, jerking, or stiffness
  • muscular pain, tenderness, wasting, or weakness
  • night blindness
  • nausea
  • overbright appearance of lights
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • restlessness
  • shuffling walk
  • skin rash, hives, or itching
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sticking out of the tongue
  • stiffness of the limbs
  • sweating
  • swollen or painful glands
  • tightness in the chest
  • trouble breathing
  • tunnel vision
  • twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
  • uncontrolled movements, especially of the face, neck, and back
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • upper right abdominal or stomach pain
  • vomiting
  • yellow eyes and skin

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

Symptoms of overdose
  • Cold, clammy skin
  • decreased urine
  • drowsiness
  • dry mouth
  • fast, weak pulse
  • increased thirst
  • lightheadedness, dizziness, or fainting
  • loss of appetite
  • muscle pain or cramps
  • numbness or tingling in the hands, feet, or lips

Some side effects of chloroquine 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
  • Change in hair color
  • hair loss
  • increased sensitivity of the skin to sunlight
  • redness or other discoloration of the skin
  • severe sunburn
  • stomach cramps
  • trouble sleeping
  • weight loss

For Healthcare Professionals

Applies to chloroquine: compounding powder, injectable solution, oral tablet


Maculopathy and macular degeneration may be irreversible.

Irreversible retinal damage has been reported in patients receiving long-term or high-dose 4-aminoquinoline therapy. Retinopathy has been reported as dose related.[Ref]

Frequency not reported: Maculopathy; macular degeneration; irreversible retinal damage; retinopathy; double vision; visual disturbances (blurred vision, focusing or accommodation difficulty); decreased visual acuity; color-vision defects; nyctalopia; scotomatous vision with field defects of paracentral, pericentral ring types, and typically temporal scotomas, (e.g., difficulty in reading with words tending to disappear, seeing half an object, misty vision, fog before the eyes); pigmentary retinopathy; corneal deposits; keratopathy; decreased corneal sensitivity; corneal edema; reversible corneal opacities[Ref]


Rare (less than 0.1%): Exfoliative dermatitis, erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome, similar desquamation-type events (including moist desquamation)
Frequency not reported: Pruritus, rashes, pleomorphic skin eruptions, lichen planus-like eruptions, urticaria, generalized exanthematous pustulosis, hair loss, increased and decreased pigmentation of the skin and mucous membranes, bleaching of hair pigment, photosensitivity, exacerbation of psoriasis[Ref]

Pruritus has been seen more commonly in Africans. The onset was generally 6 to 48 hours after the first dose and antihistamines may or may not control the pruritus.

Increased pigmentation of the skin and mucous membranes was generally of a bluish color; may not be reversible on discontinuation.

Several cases of hypopigmentation of the skin have been reported. Most of the patients described were African or of African descent with dark skin who had been exposed to the sun. One was a Hispanic patient who developed vitiligo-like skin depigmentation after 1 month of chloroquine therapy for cutaneous lupus erythematosus. The skin rapidly repigmented after discontinuation of chloroquine therapy.

At least 2 cases of exacerbation of psoriasis requiring hospitalization have been reported. Patients with psoriasis should be cautioned about the potential for exacerbation.

Generalized exanthematous pustulosis occurred in a patient during combined chloroquine-proguanil therapy.

A 12-year-old female developed moist desquamation coincident with chloroquine therapy. She was diagnosed with a diffuse pontine glioma and considered for direct radiotherapy. Before the administration of chloroquine, the patient had only a mild skin erythema in the irradiated area, which was consistent with the radiotherapy dose she had received. On day 3 of chloroquine therapy, she developed localized brisk bullous eruptions in the irradiated area, which developed into a patch of fulminant moist desquamation. After radiotherapy was withheld for 1 week, the moist desquamation had almost healed. Chloroquine seemed to be the most probable cause for the adverse event.[Ref]


Frequency not reported: Neuropsychiatric changes, psychosis, mania, delirium, anxiety, agitation, insomnia, confusion, personality changes, depression, other psychiatric and neurologic disturbances, development of extrapyramidal rigidity, paranoia, hallucinations[Ref]

Mania has been reported in a patient taking chloroquine for malarial prophylaxis. These symptoms resolved after discontinuation and recurred with rechallenge.[Ref]


Frequency not reported: Nausea, vomiting, diarrhea, abdominal pain, abdominal cramps[Ref]

Nervous system

Frequency not reported: Mild and transient headache, convulsive seizures, polyneuritis, dizziness, nerve type deafness, tinnitus, reduced hearing (in patients with preexisting auditory damage), acute extrapyramidal disorders (e.g., dystonia, dyskinesia, tongue protrusion, torticollis), nonconvulsive status epilepticus/seizures[Ref]


Myopathies and myasthenia-like syndromes are often reversible following discontinuation or dose reduction.

These side effects were seen most often in patients receiving large doses for treatment of lupus or rheumatoid arthritis; however, such reactions have been noted in patients taking therapeutic doses for short periods. Symptoms often resolved over time with a reduction of the dose or discontinuation of chloroquine (the active ingredient contained in Aralen) [Ref]

Frequency not reported: Skeletal muscle myopathy or neuromyopathy leading to progressive weakness and atrophy of proximal muscle groups (may be associated with mild sensory changes, tendon reflex depression, abnormal nerve conduction), myopathies, myasthenia-like syndromes[Ref]


Rare (less than 0.1%): Hypotension, cardiomyopathy, electrocardiographic change (particularly, inversion or depression of the T-wave with widening of the QRS complex)
Frequency not reported: Cardiac hypertrophy, restrictive cardiomyopathy, congestive heart failure, complete heart block, conduction disorders[Ref]

Electrocardiographic changes observed included prolongation of the QRS interval and, rarely, complete heart block. Biopsies of cardiac tissue characteristically showed no inflammatory infiltrates, severe vacuolation, and myocytes containing myeloid bodies and lysosomes.[Ref]


Frequency not reported: Anaphylactic/anaphylactoid reaction (including angioedema), drug rash with eosinophilia and systemic symptoms (DRESS syndrome)


Frequency not reported: Anorexia, hypokalemia associated with acute ingestion, hypercalcemia associated with sarcoidosis[Ref]

The usefulness of hypokalemia as an indicator in the evaluation of chloroquine toxicity was studied in a retrospective series of 191 acute chloroquine poisonings. Results indicated that the risk of severe poisoning and death are proportional to the degree of hypokalemia.

Hypercalcemia associated with sarcoidosis has been corrected within days after the use of chloroquine.[Ref]


Rare (less than 0.1%): Pancytopenia, aplastic anemia, reversible agranulocytosis, thrombocytopenia, neutropenia[Ref]


Frequency not reported: Hepatitis, elevated liver enzymes, hepatotoxicity (in a patient with porphyria cutanea tarda)[Ref]


Frequency not reported: Pain at site of IM injections which lasted 15 minutes to 2 hours[Ref]

Some side effects of Aralen may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Chloroquine Pregnancy Warnings

Chloroquine has not been formally assigned to a pregnancy category by the FDA. There are no controlled data in human pregnancies. Congenital anomalies were reported in the offspring of one woman being treated with chloroquine 250 to 500 mg daily during pregnancy for SLE; however, chloroquine has been used in the prophylaxis and treatment of malaria during pregnancy without evidence of fetal harm. Chloroquine is the drug of choice for the prophylaxis and treatment of sensitive malaria species during pregnancy. Chloroquine should only be given during pregnancy when need has been clearly established.