Last reviewed 2026-04-20 · How we verify

Aralen (CHLOROQUINE)

Aralen works by accumulating in the acidic compartments of the malaria parasite, disrupting its metabolism and ultimately leading to its death.

Aralen (Chloroquine) is a small molecule antimalarial medication originally developed by Sanofi-Aventis US and currently owned by the same company. It targets the Sigma non-opioid intracellular receptor 1 and has been FDA-approved since 1949 for various malaria-related conditions. Aralen is off-patent and has no active Orange Book patents, allowing for generic manufacturing. It has a long half-life of 570 hours and high bioavailability of 80%. As an off-patent medication, it is available from generic manufacturers.

At a glance

Mechanism of action

Mechanism of Action: Chloroquine, 4-aminoquinoline, is an anti-protozoal agent. The precise mechanism by which chloroquine exhibits activity is not known. Chloroquine, may exert its effect against Plasmodium species by concentrating in the acid vesicles of the parasite and by inhibiting polymerization of heme. It can also inhibit certain enzymes by its interaction with DNA. Activity in Vitro and in Clinical Infections: Chloroquine is active against the erythrocytic forms of susceptible strains of Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax. Chloroquine is not active against the gametocytes and the exoerythrocytic forms including the hypnozoite stage (P. vivax and P. ovale) of the Plasmodium parasites. In vitro studies with Chloroquine demonstrated that it is active against the trophozoites of Entamoeba histolytica. Drug Resistance: Resistance of Plasmodium parasites to chloroquine is widespread (see INDICATIONS AND USAGE, Limitations of Use in Mal

Approved indications

• Discoid lupus erythematosus
• Falciparum malaria
• Malaria Prevention
• Ovale malaria
• Plasmodium Falciparum Malaria Prevention
• Plasmodium Malariae Malaria Prevention
• Plasmodium Ovale Malaria Prevention
• Quartan malaria
• Rheumatoid arthritis
• Systemic lupus erythematosus
• Vivax malaria

Common side effects

• Hepatitis
• Pancytopenia
• Aplastic anemia
• Reversible agranulocytosis
• Thrombocytopenia
• Neutropenia
• Hemolytic anemia
• Cardiomyopathy
• Cardiac arrhythmias
• Conduction disorders
• QT interval prolongation
• Torsade de pointes

Drug interactions

• High Risk QT Prolonging Agents
• azithromycin
• ciclosporin
• cimetidine
• clarithromycin
• erythromycin
• praziquantel

Key clinical trials

• Akt Inhibitor MK2206 and Hydroxychloroquine in Treating Patients With Advanced Solid Tumors, Melanoma, Prostate or Kidney Cancer (PHASE1)
• Safety and Effect on Pain and Function According to RAPID-3 of IHL-675A in Patients With Rheumatoid Arthritis (PHASE2)
• Serological Testing and Treatment for Plasmodium Vivax Malaria: a Trial in Ethiopia and Madagascar (PHASE3)
• The Efficacy and Safety of Anti-inflammation Treatment (Hirudoid Introduction Followed by Yellow Light Therapy) Combined With Tofacitinib and Doxycycline in Chinese Adult Patients With Mild to Moderate Erythematous Telangiectatic Rosacea (NA)
• Hydroxychloroquin (HCQ) in chILD of Genetic Defect (NA)
• Hydroxychloroquine in Children's Interstitial Lung Diseases With Genetic Causes (EARLY_PHASE1)
• AIPH-TB: AI-Optimised Pyrazinamide-Hydroxychloroquine vs Standard RIPE for Drug-Sensitive Pulmonary Tuberculosis - A Phase II RCT (PHASE2)
• Testing Dabrafenib and Trametinib With or Without Hydroxychloroquine in Stage IIIC or IV BRAF V600E/K Melanoma (PHASE2)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.