Antimalarial / 4-aminoquinoline Pregnancy: Should not be used during pregnancy unless potential benefit outweighs risk. Short-term malaria prophylaxis may be given if travel to a malarious area is unavoidable. High-dose long-term use throughout pregnancy can cause foetal abnormalities (visual loss, ototoxicity, cochlear-vestibular dysfunction). Excreted in breast milk in amounts too small to harm or to protect the infant (separate infant chemoprophylaxis required); breast-feeding not recommended when long-term high doses used for rheumatoid disease.

Chloroquine

Brand names: Avloclor, Nivaquine

Chloroquine is a 4-aminoquinoline used for the treatment and prevention of malaria caused by susceptible Plasmodium species and for certain rheumatological and dermatological conditions.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Treatment of malaria (P. falciparum, P. malariae, P. vivax, P. ovale): a single dose of 4 tablets, followed by 2 tablets 6 hours later, then 2 tablets a day for two days

Route: Oral (take after food)

Frequency: Initial 4 tablets, then 2 tablets at 6 h, then 2 tablets daily for 2 days

Avloclor tablets. Dose above is acute malaria treatment (adults). Prophylaxis/suppression of malaria: 2 tablets once a week on the same day, starting 1 week before exposure and continuing until 4 weeks after leaving the malarious area. P. vivax/P. ovale: follow with a course of primaquine if radical cure required. Amoebic hepatitis: 4 tablets daily for 2 days, then 1 tablet twice daily for 2-3 weeks. Lupus erythematosus: 1 tablet twice daily for 1-2 weeks, then maintenance 1 tablet daily. Rheumatoid arthritis: usually 1 tablet daily. Caution in renal or hepatic disease. No special dosage for elderly but monitor to determine optimum dose. QTc prolongation risk — do not exceed the recommended dose. (US chloroquine phosphate label expresses all doses as chloroquine base and differs from this UK tablet-count regimen — verify vs UK SPC.)

Paediatric dose

Dose: 10 mg/kg

Route: Oral (after food)

Frequency: Single dose of 10 mg base/kg, followed by 5 mg base/kg 6 hours later, then 5 mg base/kg a day for two days (malaria treatment)

Max: Must not exceed the adult dose regardless of weight

Malaria treatment (children), dose expressed as chloroquine base. Age-band tablet equivalents per SPC: 1-4 yr = 1 tablet initial / 1/2 tablet second dose / 1/2 tablet on each subsequent day; 5-8 yr = 2 / 1 / 1; 9-14 yr = 3 / 1.5 / 1.5. Malaria prophylaxis (children): 5 mg chloroquine base/kg once a week (1-4 yr = 1/2 tablet, 5-8 yr = 1 tablet, 9-14 yr = 1.5 tablets); start 1 week before exposure, continue 4 weeks after leaving malarious area. Children over 14 may be treated as adults. Verify paediatric dosing against a children's formulary.

Dose adjustments

Renal

Caution necessary in patients with renal disease (no specific dose reduction stated in SPC).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Known hypersensitivity to chloroquine or any other ingredient of the formulation
Concomitant use with amiodarone

Side effects

Gastrointestinal: nausea, vomiting, diarrhoea, abdominal pain
Eye disorders: retinal degeneration, macular colour-vision defects, corneal opacity/pigmented deposits, blurred vision (long-term/high dose)
Cardiac: cardiomyopathy (rare), AV block, QT prolongation
Hypoglycaemia (including severe/loss of consciousness)
Skin: macular/urticarial/purpuric eruptions, erythema multiforme, DRESS, Stevens-Johnson syndrome, toxic epidermal necrolysis, photosensitivity

Interactions

Amiodarone (contraindicated)
QT-interval prolonging agents — increased risk of ventricular arrhythmias
Macrolide antibiotics — potential increased risk of cardiovascular events/mortality
Proguanil (DRESS syndrome reported with chloroquine alone or combined)

Clinical monograph

How it works

In malaria it is concentrated in the parasite's digestive vacuole where it interferes with haem detoxification, leading to accumulation of toxic haem and parasite death.

Prescribing in practice

Overdose is dangerous and can be rapidly fatal owing to cardiotoxicity, so quantities supplied and storage away from children must be considered carefully.
Widespread resistance limits its use for malaria in many regions, so choice must follow current malaria prophylaxis and treatment guidance.
Caution is needed in epilepsy, in psoriasis and where there is pre-existing eye disease; it is contraindicated where retinopathy is established.

Monitoring

With long-term use, baseline and periodic ophthalmological assessment is recommended because of the risk of irreversible retinal toxicity.

Counselling the patient

If taken for malaria prevention, also use mosquito-bite avoidance measures.
Report any visual disturbance promptly, and keep the medicine well out of reach of children.

Evidence & guidelines

Use follows UK malaria prevention guidelines and MHRA advice; regional resistance data determine its suitability for malaria.

Reference: UK malaria guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways