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trademark for a preparation of chloroquine, an antimalarial agent also used as a suppressant of lupus erythematosus.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


(klor-oh-kwin) ,


(trade name)


Therapeutic: antimalarials
Pregnancy Category: UK


Prophylaxis and treatment of acute attacks of malaria.Treatment of extraintestinal amebiasis.Treatment of severe rheumatoid arthritis.Treatment of systemic lupus erythematosus.


Inhibits protein synthesis in susceptible organisms by inhibiting DNA and RNA polymerase.

Therapeutic effects

Death of plasmodia responsible for causing malaria.
Death of amoeba responsible for causing amebiasis.
Improvement in inflammation in rheumatoid arthritis and systemic lupus erythematosus.


Absorption: Well absorbed following oral administration.
Distribution: Widely distributed; high tissue concentrations achieved. Crosses the placenta, enters breast milk.
Metabolism and Excretion: 30% metabolized by the liver. Metabolite also has antiplasmodial activity; 70% excreted unchanged by the kidneys.
Half-life: 3–5 days.

Time/action profile (antimalarial activity)

POrapid1–2 hrdays–wks


Contraindicated in: Hypersensitivity; Hypersensitivity to other 4-aminoquinolones (hydroxychloroquine); Visual damage caused by chloroquine or other 4-aminoquinolones; Lactation: Potential for serious adverse reactions in nursing infants.
Use Cautiously in: Liver disease; Alcoholism; Patients receiving hepatotoxic drugs; Porphyria (may exacerbate condition); Psoriasis; genetic implication G6PD deficiency (↑ risk of severe hemolysis); Bone marrow depression; Hearing impairment; Epilepsy; Obstetric: Although safety not established, has been used; Pediatric: Extremely sensitive to chloroquine effects; Geriatric: May be predisposed to adverse effects.

Adverse Reactions/Side Effects

Central nervous system

  • seizures (life-threatening)
  • anxiety
  • agitation
  • confusion
  • delirium
  • depression
  • hallucinations
  • headache
  • insomnia
  • personality changes
  • polyneuritis
  • psychosis

Ear, Eye, Nose, Throat

  • corneal opacities (reversible)
  • hearing impairment
  • retinopathy
  • tinnitus
  • visual disturbances


  • cardiomyopathy
  • ECG changes (T-wave abnormalities, QRS prolongation)
  • hypotension


  • abdominal cramps
  • anorexia
  • diarrhea
  • hepatitis
  • ↑ liver enzymes
  • nausea
  • vomiting


  • stevens-johnson syndrome (life-threatening)
  • toxic epidermal necrolysis (life-threatening)
  • alopecia
  • dermatoses
  • photosensitivity
  • pigmentary changes
  • pruritus
  • skin eruptions
  • urticaria


  • agranulocytosis (life-threatening)
  • aplastic anemia (life-threatening)
  • leukopenia (life-threatening)
  • thrombocytopenia


  • neuromyopathy
  • peripheral neuritis
  • weakness


Drug-Drug interaction

Antacids may ↓ absorption (separate administration of these agents by at least 4 hr).Blood levels may be ↑ by cimetidine,fluconazole,ketoconazole,clarithromycin,erythromycin,fluoxetine,nefazodone,paroxetine,protease inhibitors,quinidine,ritonavir, and verapamil (concurrent use with cimetidine, should be avoided).May ↓ absorption of ampicillin (separate administration of these agents by at least 2 hr).May ↑ blood levels of cyclosporine,fluoxetine,lidocaine,mirtazapine,nefazodone,paroxetine,risperidone,ritonavir,thioridazine,tricyclic antidepressants, and venlafaxine.Blood levels may be ↓ by carbamazepine,nevirapine,phenobarbital,phenytoin, and rifampin.May ↑ the risk of hepatotoxicity when administered with other hepatotoxic agents.Urinary acidifiers may ↑ renal excretion and ↓ effectiveness.Concurrent use with mefloquine may ↑ risk of seizures.Foods that acidify urine (see ) may ↑ excretion and ↓ effectiveness.


Doses below expressed as chloroquine base: 1 mg of chloroquine base = 1.67 mg chloroquine phosphate or 1.25 mg chloroquine hydrochlorideSuppression/Prophylaxis of Malaria
Oral (Adults) 300 mg once weekly, starting 2 wk prior to entering endemic areas and for 8 wk afterward. If suppressive therapy is not initiated prior to entering endemic area, initial dose should be 300 mg followed by another 300 mg dose 6 hr later, followed by the usual dosage regimen.
Oral (Children) 5 mg/kg once weekly, starting 2 wk prior to entering endemic areas and for 8 wk afterward (not to exceed 300 mg/day).If suppressive therapy is not initiated prior to entering endemic area, initial dose should be 5 mg/kg followed by another 5 mg/kg dose 6 hr later, followed by the usual dosage regimen.
Treatment of Acute Attack of Malaria
Oral (Adults) 600 mg initially, then 300 mg at 6–8 hr, 24 hr, and 48 hr after initial dose.
Oral (Children) 10 mg/kg initially (not to exceed 600 mg), then 5 mg/kg at 6 hr, 24 hr, and 48 hr after initial dose (not to exceed 300 mg/day).
Extraintestinal Amebiasis
Oral (Adults) 600 mg daily for 2 days, then 300 mg daily for at least 2–3 wk (in combination with other antiprotozoals).
Oral (Children) 10 mg/kg (not to exceed 300 mg/day for 2–3 wk.
Rheumatoid Arthritis/Systemic Lupus Erythematosus
Oral (Adults) 150 mg once daily; reduce dosage following maximal response.


Chloroquine Phosphate

Tablets: 250 mg (150-mg base), 500 mg (300-mg base)

Nursing implications

Nursing assessment

  • Determine baseline for future reference that includes current symptoms of disease prior to administration.
    • Assess deep tendon reflexes periodically to determine muscle weakness. If weakness occurs, discontinue therapy.
    • Discontinue therapy immediately if hearing impairment develops.
    • Perform ophthalmologic exam initially and periodically during therapy; discontinue therapy immediately if visual disturbances develop.
    • Observe for development of rash. Discontinue chloroquine at the first sign of skin reactions. Serious adverse reactions such as Stevens-Johnson syndrome or toxic epidermal necrolysis preclude further use.
  • Malaria: Assess patient for improvement in signs and symptoms of condition daily throughout therapy.
  • Rheumatoid Arthritis/Systemic Lupus Erythematosus: Assess degree of joint pain and limitation of motion monthly.
  • Lab Test Considerations: Monitor CBC periodically throughout therapy. May cause decreased WBC and platelet counts.
    • Monitor liver function tests periodically during therapy.

Potential Nursing Diagnoses

Risk for infection (Indications)
Chronic pain (Indications)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)


  • For malaria suppression/prophylaxis, chloroquine therapy should be started 2 wk prior to potential exposures and continued for 8 wk after leaving the area.
  • Oral: Administer with meals to minimize GI distress.

Patient/Family Teaching

  • Instruct patient to take medication exactly as directed and continue full course of therapy, even if feeling better. Missed doses should be taken as soon as remembered, except with regimens requiring doses more than once a day, for which missed doses should be taken within 1 hr or omitted. Do not double doses.
  • Review methods of minimizing exposure to mosquitoes with patients receiving chloroquine prophylactically (use insect repellent, wear long-sleeved shirt and long trousers, use screen or netting).
  • Advise patients to avoid use of alcohol while taking chloroquine.
  • Caution patient to keep chloroquine out of the reach of children; fatalities have occurred with ingestion of 3 or 4 tablets.
  • Explain need for periodic ophthalmic exams for patients on prolonged high-dose therapy. Advise patient that the risk of ocular damage may be decreased by the use of dark glasses in bright light. Protective clothing and sunscreen should also be used to reduce risk of dermatoses.
  • Advise patient to notify health care professional promptly if sore throat, fever, unusual bleeding or bruising, blurred vision, difficulty reading, visual changes, ringing in the ears, difficulty hearing, mental changes, or muscle weakness occurs or if diarrhea, anorexia, nausea, stomach pain, vomiting, or rash becomes pronounced or bothersome. Most adverse reactions are dose related.
  • Advise female patient to notify health care professional of pregnancy is planned or suspected, or if breastfeeding.
  • Rheumatoid Arthritis/Systemic Lupus Erythematosus: Instruct patient to contact health care professional if no improvement is noticed within a few days. Treatment may require up to 6 mo for full benefit.

Evaluation/Desired Outcomes

  • Prevention of or improvement in signs and symptoms of malaria.
  • Regression of extraintestinal amebic disease.
  • Decrease in the symptoms and progression of rheumatoid arthritis and systemic lupus erythematosus.
Drug Guide, © 2015 Farlex and Partners


A trademark for the drug chloroquine phosphate.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Chloroquine phosphate, see there.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Drugs prescribed for lupus include nonsteroidal anti-inflammatory agents, such as aspirin or ibuprofen; acetaminophen; antimalarials such as hydroxychloroquine (Plaquenil) and chloroquine (Aralen), corticosteroids such as prednisone or medrol; immune suppressants such as azathioprine (Imuran), methotrexate (Rheumatrex).
If the disease remains uncontrolled, consider replacing the hydroxychloroquine with chloroquine (Aralen) at a dosage of 3.5 mg/kg of ideal body weight per day, continuing the quinacrine.
(Plaquenil [R]) Retinal damage is Chloroquine Aralen [R]) Hydroxycholoroquine rare when the and chloroquine patient is Quinacrine may cause a monitored closely.