What is the appropriate hydroxychloroquine dosing regimen for a post‑menopausal woman with frontal fibrosing alopecia who has normal renal and hepatic function, no retinal disease, no G6PD deficiency, and is not pregnant or nursing?

Hydroxychloroquine Dosing for Frontal Fibrosing Alopecia

For a postmenopausal woman with frontal fibrosing alopecia and no contraindications, hydroxychloroquine should be dosed at 200 mg twice daily (400 mg/day total), not exceeding 5 mg/kg of actual body weight per day to minimize retinal toxicity risk. 1, 2

Specific Dosing Calculation

• Calculate the maximum safe dose using actual body weight: Multiply patient's weight in kg by 5 mg/kg to determine the ceiling dose 1
• Standard dosing is 200 mg twice daily (400 mg/day) for most dermatologic and rheumatologic conditions, which falls within safe limits for patients weighing ≥80 kg 2
• For patients <80 kg: Consider 200 mg daily or 200 mg alternating with 400 mg on alternate days to stay below the 5 mg/kg threshold 1
• Do NOT use ideal body weight for calculations—this leads to overdosing in thin patients and underdosing in others 1, 3

Evidence for Efficacy in FFA

The strongest evidence supporting hydroxychloroquine use in FFA comes from a retrospective study of 36 patients showing:

• Statistically significant reduction in signs and symptoms at both 6 and 12 months using the Lichen Planopilaris Activity Index (P < 0.05) 4
• Maximal benefits occur within the first 6 months of treatment, with no significant additional improvement between 6-12 months 4
• Hydroxychloroquine ranks among the three treatments with highest level of evidence for FFA (alongside 5-α-reductase inhibitors and intralesional steroids) 5

However, the natural history of FFA is unpredictable—some patients stabilize spontaneously while others progress despite treatment, making it difficult to definitively attribute stabilization to medication 6, 7, 8

Critical Safety Monitoring Requirements

Before Starting Treatment:

• Check G6PD levels in men of African, Asian, or Middle Eastern origin (though risk appears low in women) 1
• Baseline ophthalmologic examination is mandatory before initiating therapy 1, 2
• Baseline ECG to assess for QT prolongation risk 2

During Treatment:

• Annual ophthalmologic screening beginning after 5 years for low-risk patients (no renal disease, dose ≤5 mg/kg/day) 1
• Earlier screening (after 1 year) if risk factors present: eGFR <60 ml/min per 1.73 m², dose >5 mg/kg/day, or concomitant tamoxifen use 1
• Retinopathy risk increases dramatically with duration: <1% risk in first 5 years, <2% up to 10 years, but ~20% after 20 years even at recommended doses 1

Dose Adjustment for Renal Impairment:

• Reduce dose by 25% if eGFR <30 ml/min per 1.73 m² since hydroxychloroquine is cleared renally 1, 3

Common Pitfalls to Avoid

• Do not confuse salt and base formulations: Hydroxychloroquine sulfate 200 mg tablets contain 155 mg base 9
• Do not split tablets to achieve intermediate doses—variable dosing averages out over weeks as blood levels stabilize 1
• Do not expect hair regrowth—the goal is disease stabilization due to the scarring nature of FFA 5, 8
• Monitor for perifollicular erythema as it directly correlates with progressive disease and indicates treatment failure 7

Expected Treatment Timeline

• Assess response at 6 months—this is when maximal benefits should be evident 4
• If no improvement by 6 months, consider switching to alternative immunosuppressants (methotrexate, mycophenolate mofetil) or adding 5-α-reductase inhibitors 5, 7
• After stabilization, drug withdrawal could be attempted with frequent monitoring, though disease may reactivate 7