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ANTIPARASITIC PRODUCTS, INSECTICIDES AND REPELLENTS › ANTIPROTOZOALS › ANTIMALARIALS › Aminoquinolines
hydroxychloroquine
P01BA02
Forms & Strengths
- Tablet: 200 mg (equivalent to 155 mg base)
Adult Dosing
- Rheumatoid arthritis: 200 mg to 400 mg daily given as a single dose or in divided doses
- Systemic lupus erythematosus: 200 mg to 400 mg daily given as a single dose or in divided doses
- Malaria suppression: 400 mg once weekly on the exact same day each week
- Malaria acute attack: 800 mg initial dose, followed by 400 mg at 6 hours, 24 hours, and 48 hours
Pediatric Dosing
- Malaria suppression (children): 6.5 mg/kg base weekly, not to exceed the adult weekly dose of 400 mg base
- Malaria acute attack (children): 13 mg/kg base initially (max 800 mg base), then 6.5 mg/kg at 6, 24, and 48 hours
- Rheumatoid arthritis and lupus (pediatric): Safety and efficacy not established in controlled pediatric studies
Indications
- Treatment of rheumatoid arthritis
- Treatment of systemic lupus erythematosus
- Prophylaxis and treatment of acute attacks of malaria due to sensitive strains of Plasmodium
- Treatment of chronic discoid lupus erythematosus
Mechanism of Action
- Concentrates in acidic intracellular vesicles, raising lysosomal pH and inhibiting autoantigen presentation
- Suppresses lymphocyte proliferation and decreases production of proinflammatory cytokines such as IL-1 and IL-6
- Interferes with toll-like receptor (TLR) signaling pathways implicated in autoimmune pathogenesis
- Suppresses nucleic acid replication and interferes with parasite hemoglobin digestion in malaria
Contraindications
- Known hypersensitivity to 4-aminoquinoline compounds
- Pre-existing maculopathy or retinal field changes of any etiology
- Long-term use in children without careful risk-benefit evaluation
Adverse Reactions
- Irreversible retinal toxicity, maculopathy, and visual field defects with chronic high-dose use
- QT prolongation and life-threatening ventricular arrhythmias
- Nausea, vomiting, diarrhea, and abdominal pain
- Skin hyperpigmentation, pruritus, alopecia, and exacerbation of psoriasis
- Myopathy, neuromyopathy, and skeletal muscle weakness
- Severe hypoglycemia
Drug Interactions
- Co-administration with QT-prolonging drugs (e.g., amiodarone, azithromycin, antipsychotics) increases arrhythmia risk
- May increase plasma concentrations of digoxin, requiring therapeutic drug monitoring
- Antacids and kaolin can decrease gastrointestinal absorption of hydroxychloroquine
- May lower the seizure threshold, antagonizing the effect of anticonvulsants
- Concurrent use with insulin or oral antidiabetic agents may enhance hypoglycemic effects
Curated Content: Needs Vetting Before Put to Clinical Use