What is the appropriate dosage and usage of Hydroxychloroquine (HCQ) 200 mg?

Hydroxychloroquine 200 mg: Dosing and Usage Guidelines

For rheumatic diseases, hydroxychloroquine should be dosed at ≤5 mg/kg actual body weight per day, which typically translates to 200-400 mg daily for most adults, with the 200 mg tablet taken once or twice daily depending on the indication. 1, 2

Standard Dosing by Indication

Systemic Lupus Erythematosus (SLE)

• 200 mg once daily OR 400 mg once daily (or in two divided doses) 2
• The ≤5 mg/kg actual body weight limit is critical—exceeding this increases retinopathy risk from <2% to ~10% after 10 years 1
• All SLE patients should receive hydroxychloroquine due to proven benefits in reducing flares, organ damage, infections, thrombosis, and improving survival 3, 4

Rheumatoid Arthritis

• Initial: 400-600 mg daily as single or divided doses 2
• Maintenance: 200 mg once daily to 400 mg daily 2
• Therapeutic effect is cumulative and may require weeks to months 2

Chronic Discoid Lupus Erythematosus

• 200 mg once daily OR 400 mg once daily (or in two divided doses) 2

Chronic Q Fever

• 200 mg three times daily (600 mg/day total) in combination with doxycycline 100 mg twice daily 1
• Treatment duration: 18-24 months depending on valve involvement 1
• Monthly plasma level monitoring required (target 0.8-1.2 μg/mL) 1, 5

Critical Dosing Adjustments

Renal Impairment

• Reduce dose by 25% when eGFR <30 mL/min/1.73 m² 5, 3
• Reduced renal function is the single greatest modifiable risk factor for retinopathy because the drug is renally excreted 1
• Patients with eGFR <60 mL/min/1.73 m² require earlier ophthalmologic screening (after 1 year instead of 5 years) 3

Body Weight Considerations

• Always calculate dose using actual body weight, not ideal body weight 1, 3
• Retinopathy risk remains consistent across BMI 15-35 kg/m² when actual body weight is used for dosing 1
• A common pitfall is using ideal body weight, which can lead to underdosing in heavier patients or overdosing in lighter patients 3

Administration

• Take with food or milk to minimize gastrointestinal side effects 2
• Do not crush or divide tablets 2
• Common GI side effects (nausea, vomiting, diarrhea, abdominal pain) generally do not require discontinuation 5, 2

Mandatory Monitoring Protocol

Ophthalmologic Screening

• Baseline examination within first few months of therapy 5, 3
• Annual screening beginning after 5 years for low-risk patients 1, 5, 3
• Annual screening beginning after 1 year for high-risk patients 5, 3

High-risk criteria requiring earlier screening include:

• Daily dose >5 mg/kg actual body weight 1, 3
• eGFR <60 mL/min/1.73 m² 3
• Concomitant tamoxifen use 1, 3
• Pre-existing retinal or macular disease 3

Special Population Considerations

• East Asian patients require screening beyond central macula because retinopathy often appears along pericentral vascular arcades rather than the classic parafoveal "bull's-eye" pattern 1, 3
• Check G6PD levels in men of African, Asian, or Middle Eastern origin before starting therapy due to hemolysis risk 5, 3

Cardiac Monitoring

• Baseline ECG recommended due to potential QT prolongation risk 5
• However, large population studies show hydroxychloroquine does not increase cardiac arrhythmia risk in rheumatic diseases, even at doses ≥400 mg daily 6

Absolute Contraindications

• Hypersensitivity to 4-aminoquinoline compounds 2
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency 1, 5
• Pre-existing retinal or visual field deficits 1, 5

Relative Contraindications and Cautions

• Psoriasis: Hydroxychloroquine can exacerbate psoriasis and should be avoided 5, 2
• Porphyria: Avoid use; hepatotoxicity reported in porphyria cutanea tarda 2

Common Pitfalls to Avoid

1. Underdosing: Doses of 2-3 mg/kg/day may not achieve adequate blood levels and are associated with higher flare rates in lupus nephritis 3

2. Premature discontinuation: The goal is to safely maintain hydroxychloroquine as long as possible, not to discontinue it casually for borderline ophthalmologic findings 1, 3

3. Inadequate monitoring in East Asian patients: Standard central macular screening may miss early pericentral toxicity in this population 3

4. Failing to adjust for renal impairment: This is the most important modifiable risk factor and must not be overlooked 1

5. Using ideal body weight instead of actual body weight: This leads to incorrect dosing and either increased toxicity risk or therapeutic failure 1, 3

Malaria Dosing (For Completeness)

While not the primary use of the 200 mg tablet in most clinical contexts:

• Prophylaxis: 400 mg once weekly (adults), starting 2 weeks before travel, continuing during exposure, and for 4 weeks after leaving endemic area 2
• Treatment of uncomplicated malaria: 800 mg initially, then 400 mg at 6,24, and 48 hours (total 2000 mg) 2
• Hydroxychloroquine is NOT recommended for chloroquine-resistant malaria strains 2, 7

COVID-19 Note

Current evidence does not support routine use of hydroxychloroquine for COVID-19 treatment 5. The 2020 guidelines suggesting various COVID-19 dosing regimens 1 have been superseded by subsequent evidence showing lack of efficacy.