Plaquenil Dosing Calculator

Plaquenil (Hydroxychloroquine) is commonly prescribed for the treatment of autoimmune diseases such as lupus and rheumatoid arthritis, and also for malaria prevention and treatment. Correct dosing is essential to ensure therapeutic efficacy while minimizing the risk of toxicity.

Key Considerations for Plaquenil Dosing

• Indication:
  • Rheumatoid Arthritis
  • Lupus (Systemic Lupus Erythematosus)
  • Malaria Treatment and Prophylaxis
• Patient Factors:
  • Age: Dosing may vary for pediatric and adult patients.
  • Body Weight: Dosing is commonly weight-based, particularly in adults.
  • Renal or Hepatic Impairment: Adjustments may be needed for patients with kidney or liver dysfunction.

Dosing Guidelines

1. Adult Dosing:

• Rheumatoid Arthritis:
  • Initial: 400–600 mg daily (divided into 2 doses) for 4–12 weeks.
  • Maintenance: 200–400 mg daily.
• Lupus (SLE):
  • Initial: 400–600 mg daily for 4–12 weeks.
  • Maintenance: 200–400 mg daily.
• Malaria Treatment:
  • Initial: 800 mg (as two 400 mg doses, 6 hours apart).
  • Follow-up: 400 mg after 24, 48, and 72 hours.
• Malaria Prophylaxis:
  • 400 mg once weekly, starting 1–2 weeks before travel and continuing for 4 weeks after exposure.

2. Pediatric Dosing:

• Rheumatoid Arthritis or Lupus:
  • 5 mg/kg/day (typically divided into 2 doses).
• Malaria Treatment:
  • 10 mg/kg/day for the first 2 days, then 5 mg/kg/day for 2–3 more days (based on clinical guidance).
• Malaria Prophylaxis:
  • 5 mg/kg once weekly.

Dosing Calculator Algorithm

1. Input Fields:

• Patient's weight (kg or lbs)
• Indication (e.g., RA, Lupus, Malaria Treatment, Malaria Prophylaxis)
• Patient’s age (for pediatric dosing)
• Renal function (if applicable)

2. Calculation Logic: Based on inputs, the calculator suggests appropriate dosing:

• Example: 70 kg adult with lupus → 400 mg daily.
• Example: 10-year-old child weighing 30 kg → 150 mg daily for autoimmune conditions.

3. Dose Rounding: Round to the nearest available tablet strength (typically 200 mg or 400 mg). If a dose falls between two options, round up for therapeutic effectiveness (unless contraindicated).

Warnings & Alerts

• Toxicity Risks: Includes retinal toxicity, cardiac arrhythmias, and gastrointestinal symptoms. Monitor closely during long-term use.
• Drug Interactions: Check for interactions, especially with medications affecting liver, kidney, or heart function.

Monitoring

• Eye Exams: Regular ophthalmologic exams are recommended for patients on long-term Plaquenil therapy to detect early signs of retinal damage.
• Renal & Hepatic Function: Monitor kidney and liver function periodically, especially in patients with pre-existing conditions.