Chloroquine
ARALEN
What it isAntimalarial raising lysosomal pH; malaria and amoebic liver abscess.
Why this oneCheap and effective where resistance has not emerged.
What limits itRetinopathy with cumulative dose, QT prolongation, and a very narrow margin — pediatric ingestion of a few tablets can be fatal.
FDA-approved for
- malaria (~1949)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Malaria prophylaxis (chloroquine-sensitive) | Adult | 500 mg (300 mg base) once weekly | 500 mg weekly, same day each week | |
| Malaria prophylaxis | Peds | 5 mg base/kg once weekly (never exceed adult dose) | 5 mg base/kg weekly | |
| Uncomplicated malaria (treatment) | Adult | 1 g (600 mg base), then 500 mg at 6-8 h, then 500 mg QD x2 days | total 2.5 g (1.5 g base) over 3 days | |
| Uncomplicated malaria (treatment) | Peds | 10 mg base/kg, then 5 mg base/kg at 6, 24, 36 h | total 25 mg base/kg |
Renal No specific adjustment given; substantially renally excreted — toxicity risk greater in renal impairment (monitor renal function); subnormal GFR increases retinopathy risk
Hepatic No specific adjustment given; concentrates in liver — use with caution in hepatic disease, alcoholism, or with hepatotoxic drugs
Prophylaxis dosed on the same day each week; treatment doses spaced at 6, 24, and 36 h
Instructions
- Prophylaxis: begin 2 weeks before exposure, continue 8 weeks after leaving endemic area
- P. vivax/P. ovale: add an 8-aminoquinoline for radical cure
- Pediatric dose never to exceed adult dose
Contraindications
- Retinal or visual field changes of any etiology (for indications other than acute malaria)
Cautions
- Not effective against chloroquine-/hydroxychloroquine-resistant Plasmodium strains — verify regional susceptibility (CDC) before prophylaxis.
- Fatal/life-threatening cardiotoxicity: cardiomyopathy, QT prolongation, torsades de pointes, ventricular arrhythmias — caution with cardiac disease, ventricular arrhythmia history, uncorrected hypokalemia/hypomagnesemia, bradycardia <50 bpm, or QT-prolonging drugs.
- Irreversible retinal damage — baseline ophthalmologic exam within first year, then per risk; higher risk with >2.3 mg/kg/day (phosphate), >5 years use, subnormal GFR, tamoxifen, macular disease.
- Severe, potentially life-threatening hypoglycemia (with or without antidiabetic drugs).
- Skeletal muscle myopathy/neuropathy — assess strength and deep tendon reflexes periodically on long-term therapy.
- Hemolysis in G6PD deficiency; periodic CBC on prolonged therapy.
- May precipitate severe psoriasis attack or exacerbate porphyria.
- Extrapyramidal disorders; may increase convulsion risk in epilepsy.
- Renal toxicity (proteinuria, phospholipidosis); accidental ingestion by children can be fatal in small doses.
- Caution with preexisting auditory damage — discontinue immediately if hearing defects occur.
Adverse reactions
- Retinopathy/maculopathy (may be irreversible)
- Visual disturbances
- Deafness/tinnitus
- Myopathy/neuromyopathy
- Hepatitis
- GI upset (nausea, vomiting, diarrhea, cramps)
- SJS/TEN/DRESS
- Pancytopenia/agranulocytosis
- Hemolytic anemia in G6PD deficiency
Pregnancy Human observational data at recommended antimalarial doses show no increase in birth defects or spontaneous abortion; animal embryo-fetal toxicity at ~3–16× MRHD — review individual benefit-risk before prescribing in pregnancy.
Lactation Excreted in breast milk (infant receives up to ~0.7% of maternal dose) — decide whether to discontinue nursing or drug; breastfed infant still requires separate malaria chemoprophylaxis.
NO BOXED WARNINGS
Principal riskRetinopathy; a few tablets can be fatal to a child
Cost, est. cash$10–$300/month
Generic entry1982
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityA small overdose can cause rapid hypotension, ventricular dysrhythmia, seizures and death.
Mechanism of action: Chloroquine ballicule
