hydroxychloroquine sulfate (Plaquenil)
Classes: Antimalarials; Immunosuppressants; DMARDs, Other; Antimalarials, Aminoquinoline
Dosing and uses of Plaquenil (hydroxychloroquine sulfate)
Adult dosage forms and strengths
tablet
- 200mg
Malaria
Plasmodium malariae, P ovale, P vivax, or susceptible strains of P falciparum
Acute treatment
- 800 mg (620 mg base) PO, then 400 mg (310 mg base) PO 6-8 hours later, then 400 mg (310 mg base) PO at 24 and 48 hours
Prophylaxis
- 400 mg (310 mg base) PO weekly, starting 2 weeks before exposure and continued for 4 weeks after departure from area
- With prolonged therapy, obtain CBCs periodically
Rheumatoid Arthritis
400-600 mg (310-465 mg base) PO daily for 4-12 weeks; maintenance: 200-400 mg (155-310 mg base) PO daily
With prolonged therapy, obtain CBCs periodically
Systemic Lupus Erythematosus
400 mg (310 mg base) PO once or twice daily; maintenance: 200-400 mg (155-310 mg base) PO daily
With prolonged therapy, obtain CBCs periodically
Porphyria Cutanea Tarda (Off-label)
100-200 mg (77.5-155 mg base) PO 2-3 times/wk
Administration
Take with food or milk
Pediatric dosage forms and strengths
tablet
- 200mg
Malaria
Plasmodium malariae, P ovale, P vivax, or susceptible strains of P falciparum
Acute treatment
- 13 mg/kg base PO, then 6.5 mg/kg base PO 6 hr later, then 6.5 mg/kg base PO at 24 and 48 hours; not to exceed 400 mg/day base
Prophylaxis
- 6.5 mg/kg base (not to exceed 400 mg [310 mg base]) PO weekly, starting 2 weeks before exposure and continued for 4 weeks after departure from area
- With prolonged therapy, obtain CBCs periodically
Porphyria Cutanea Tarda (Off-label)
Dosing schedules not well established in children
A case report describes 3 mg/kg PO twice weekly over 14 months reported as safe and effective in a child aged 4 yr
Administration
Take with food or milk
Plaquenil (hydroxychloroquine sulfate) adverse (side) effects
Frequency not defined
Nausea, vomiting
Headache
Dizziness
Irritability
Muscle weakness
Aplastic anemia
Leukopenia
Thrombocytopenia
Corneal changes or deposits (visual disturbances, blurred vision, photophobia; reversible on discontinuance)
Retinal damage with long-term use
Bleaching of hair
Alopecia
Pruritus
Skin and musculoskeletal pigmentation changes
Weight loss, anorexia
Cardiomyopathy (rare)
Warnings
Black box warnings
Should be prescribed by experienced physician familiar with complete contents of package insert
Contraindications
Hypersensitivity to 4-aminoquinoline derivatives
Retinal or visual field changes due to 4-aminoquinoline compounds
Long-term therapy in children
Cautions
Discontinue in 6 months if improvement is inadequate
Exacerbates psoriasis and porphyria; use with caution
Retinal damage and loss of visual acuity may occur with long-term use; perform periodic ophthalmologic examinations
Hepatic disease or alcoholism
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with hemolysis and renal impairment; use with caution
Patients are prone to dermatitis outbreaks
Cardiomyopathy (rare) is reported with long-term use
Hematologic reactions (including aplastic anemia) and agranulocytosis may occur
Myopathy and neuromyopathy and muscle weakness are associated with aminoquinolone derivatives; assess muscle strength periodically
May exacerbate heart failure
Pregnancy and lactation
Pregnancy category: C
Lactation: Drug is concentrated in breast milk (American Academy of Pediatrics committee states that it is compatible with nursing)
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Plaquenil (hydroxychloroquine sulfate)
Mechanism of action
Unknown; may impair complement-dependent antigen-antibody reactions; inhibits locomotion of neutrophils and chemotaxis of eosinophils
Increases pH and interferes with lysosomal degradation of hemoglobin, which in turn interferes with digestive vacuole function
Absorption
Bioavailability: Rapid and complete absorption
Onset: May take 4-6 months to show response; peak response takes several months (rheumatic disease)
Duration: Unknown
Peak plasma time: 1-3 hr
Distribution
Protein bound: 55%
Metabolism
Metabolites: Desethylhydroxychloroquine, desethylchloroquine
Elimination
Half-life: 32-50 days
Excretion: Urine (60%)