hydroxychloroquine sulfate (Plaquenil)

Dosing and uses of Plaquenil (hydroxychloroquine sulfate)

• Adult
• Pediatric

 

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%)