Aralen (Chloroquine)

Aralen (Chloroquine): Patient-Friendly Australian Medicine Guide

Basic Product Information

Mechanism of Action

For patients: Aralen (Chloroquine) works by entering red blood cells infected with malaria parasites, where it stops the parasites from growing and multiplying. It does this by raising the pH inside certain cell compartments, which interferes with the parasite’s normal functions.

For health professionals: Chloroquine is a 4-aminoquinoline compound. It acts by suppressing asexual erythrocytic forms of malaria parasites and interfering with heme polymerisation, leading to accumulation of toxic heme and parasite death. It also increases endosomal pH, disrupting cellular processes within the parasite.

Pharmacokinetics

• Absorption: Rapidly and almost completely absorbed after oral administration.
• Metabolism: Liver (hepatic) metabolism primarily by CYP2C8 and CYP3A4 enzymes.
• Elimination: Mainly excreted via the kidneys (urine), with some biliary excretion.
• Onset, Peak, and Duration: Detectable in blood within 30–60 mins; peak plasma concentration in 1–3 hours; terminal elimination half-life is 1–2 months due to tissue binding.

This long half-life allows for once weekly dosing for malaria prophylaxis.

Use in Everyday Life and Best Practices

• Always take Aralen as prescribed by your doctor. Do not alter your dose or frequency without consulting your General Practitioner (GP) or pharmacist.
• Malaria prevention: Typically, chloroquine is started 1 week before entering a malaria-risk area, continued weekly during your stay, and for 4 weeks after leaving.
• For malaria treatment or other uses (such as certain autoimmune diseases), follow the dose and schedule outlined for your specific condition.
• If you miss a dose and it is within 12 hours, take it as soon as possible. If more than 12 hours have passed, skip and return to your regular schedule. Do not double doses.
• Store at room temperature, away from direct sunlight and heat (typical for English homes).

Dosing: Morning vs Evening

• Morning dosing: May make it easier to remember (with breakfast), ensures alertness to monitor side effects. Some patients experience fewer sleep disturbances if taken in the morning.
• Evening dosing: Convenient for those with busy days, but may risk forgetting if daily routine varies.
• Tip: Take at the same time each week (for prophylaxis) or each day to build a routine. Smartphone reminders or pillboxes are helpful.

Taken With Food or on an Empty Stomach

• Taking Chloroquine with food or a glass of milk can reduce stomach upset, which is a common side effect.
• In Australia, a typical meal (with cereals, toast, or porridge for breakfast, and sandwiches or pasta for lunch) is suitable to buffer the stomach.
• If you experience nausea, always take with or after a meal.
• No major interaction with most common English/Australian foods. Grapefruit should be avoided as it may affect medicine metabolism.

Interactions Warnings

Indications

*Chloroquine is much less commonly used in autoimmune conditions in Australia; hydroxychloroquine (Plaquenil) is preferred for safety and regulatory reasons.

Dosing According to Clinical Indications

Please note your doctor will tailor the dose for your needs and health status.

Safety Profile & Side Effects

Common Side Effects (mild)

• Stomach upset, nausea, vomiting
• Diarrhoea
• Headache, dizziness
• Itching
• Blurred vision (short-term, reversible in most cases)
• Loss of appetite, weight loss

Serious/Rare Side Effects

• Retinopathy (can cause irreversible vision loss with long-term use or high doses)
• Cardiac arrhythmia (irregular heartbeat — higher risk with other medicines prolonging QT)
• Severe skin reactions (rash, peeling)
• Seizures (rare)
• Bone marrow suppression (very rare)
• Muscle weakness, hearing loss (rare)

See a doctor immediately if you notice: heart palpitations, severe rash, severe vision changes, unexplained weakness, mental/mood changes.

Guidelines for Proper Use

1. Take your full course, even if you feel well, especially for malaria prevention.
2. Use a calendar or app to track weekly doses.
3. Have regular eye tests every 6–12 months if on long-term treatment. Keep records and share them with your optometrist/ophthalmologist.
4. Do not share your medicine with others or self-prescribe.
5. Discuss with your pharmacist any other medicines or supplements you take, including over-the-counter products and vitamins.
6. Women who are pregnant or breastfeeding: Consult your GP or obstetrician — chloroquine may be used but only if medically necessary.
7. Dispose of unused medicine safely with your local pharmacy’s return service.

Alternative Treatment Options

• Hydroxychloroquine (Plaquenil): Preferred for long-term use in rheumatoid arthritis/lupus; similar action but lower risk of eye toxicity.
• Mefloquine, Doxycycline, Atovaquone/Proguanil (Malarone): Alternatives for malaria prophylaxis or treatment where chloroquine resistance is common (e.g., much of Africa, Asia, Papua New Guinea).
• Artemisinin-based therapies: Used for malaria treatment (not prevention), especially for P. falciparum and resistant strains.
• Comparative overview:
  • Chloroquine: Well-tolerated, cheap, but not effective in resistant areas.
  • Hydroxychloroquine: Safer for eyes/liver with long-term use, does not treat malaria.
  • Mefloquine/Doxycycline: For resistant regions, but may cause psychiatric or gastrointestinal side effects.

Medicare Australia may reimburse some antimalarial drugs; check PBS for current status.

Legal, Registration, and Reimbursement Status in Australia

• Regulatory Authority: Therapeutic Goods Administration (TGA)
• Legal status: Schedule 4 (Prescription only)
• Reimbursement: Some formulations are available under the Pharmaceutical Benefits Scheme (PBS) for specific indications
• Controlled substance: Not a controlled drug, but may be subject to increased oversight in remote and Indigenous communities to prevent misuse
• Supply may be limited in some remote regions of Australia

Latest Research and Clinical Guidance (2022–2025)

• Recent clinical reviews (Australian Prescriber, MJA, 2024) confirm that chloroquine remains effective for malaria prevention in regions without resistance.
• It is not recommended for COVID-19 prevention or treatment (Australian guidelines, 2022-onward).
• Hydroxychloroquine is preferred for rheumatoid arthritis and lupus due to a better safety profile (TGA and RACGP guidance).
• PBS does not currently extend reimbursement for chloroquine in COVID-19 or other non-malarial indications.
• For paediatrics: Dosing must be individually calculated; overdose in children can be rapidly fatal — always keep out of reach and supervise medication use closely.

References: Australian Therapeutic Guidelines (TG), TGA safety bulletins, RACGP care pathways, Australian Medicines Handbook (last update: December 2024).

Availability and Delivery

Prices and availability may vary; prescriptions are needed for ordering. Delivery times depend on local supply and courier services. Rural and remote areas may see additional delays.

Frequently Asked Questions (FAQ)

1. Can I buy Aralen (Chloroquine) over the counter in Australia?
   No, it is a prescription-only medicine. You need a valid prescription from your doctor to buy it at any Australian pharmacy.
2. Does Aralen (Chloroquine) cause permanent eye damage?
   Long-term use at high doses can cause permanent eye damage (retinopathy), but this is very rare at routine doses for malaria. If you need prolonged use, your doctor will schedule regular eye checks to ensure safety.
3. Can I take Chloroquine if I'm pregnant or breastfeeding?
   In some cases, Chloroquine can be used in pregnancy and breastfeeding when the benefits outweigh any potential risks. Discuss with your GP, especially if you require malaria prevention.
4. What should I do if I forget a dose?
   Take it as soon as you remember if it is within 12 hours. If more than 12 hours have passed, skip the dose and continue with your next scheduled dose. Do not double up to make up for a missed dose.
5. Does it interact with vaccinations or travel medicines?
   Chloroquine is generally safe with most vaccines, but always inform your immunisation clinic or GP you are taking it, especially for live vaccines.