Hydroxychloroquine Usage and Dosage Guidelines
Hydroxychloroquine should be dosed at less than 5.0 mg/kg of actual body weight daily for most conditions to minimize the risk of retinal toxicity, with specific dosing protocols varying by indication. 1, 2, 3
Dosage Guidelines by Indication
Rheumatoid Arthritis
- Initial dose: 400-600 mg (310-465 mg base) daily, as a single dose or divided into two doses 3
- Maintenance dose: 200-400 mg (155-310 mg base) daily, as a single dose or divided into two doses 3
- Maximum dose: Do not exceed 600 mg or 5.0 mg/kg actual body weight per day, whichever is lower 1, 2, 3
Systemic Lupus Erythematosus
- Recommended dose: 200-400 mg (155-310 mg base) daily, as a single dose or divided into two doses 3
- Maximum dose: 400 mg daily 3
Malaria Prophylaxis
- Adults: 400 mg (310 mg base) once weekly on the same day, starting 2 weeks before exposure and continuing for 4 weeks after leaving endemic area 3
- Weight-based dosing: 6.5 mg/kg (5 mg/kg base), not exceeding 400 mg (310 mg base) once weekly 3
Treatment of Uncomplicated Malaria
- Adults: 800 mg (620 mg base) followed by 400 mg (310 mg base) at 6 hours, 24 hours, and 48 hours after initial dose 3
- Weight-based dosing: 13 mg/kg (10 mg/kg base), not exceeding 800 mg (620 mg base), followed by 6.5 mg/kg (5 mg/kg base), not exceeding 400 mg (310 mg base) at 6,24, and 48 hours 3
- For P. vivax and P. malariae infections, concomitant therapy with an 8-aminoquinoline compound is necessary 3
Chloroquine Dosing
- Chloroquine is more toxic than hydroxychloroquine 1
- Equivalent of 5.0 mg/kg hydroxychloroquine would be approximately 2.3 mg/kg chloroquine 1
Monitoring and Safety
Baseline Evaluation
- Complete blood count, liver function tests, renal function tests, G6PD levels, and ECG 2
- Ocular examination within first year of treatment 2
Ongoing Monitoring
- Annual laboratory monitoring (CBC, liver function tests) 2
- Ophthalmologic screening:
- Baseline exam within first year
- Annual screening after 5 years of treatment for low-risk patients
- More frequent monitoring for high-risk patients 2
High-Risk Factors for Retinopathy
- Daily dosage >5.0 mg/kg actual body weight
- Treatment duration >5 years
- Renal disease (reduce dose by 25% if eGFR <30 ml/min/1.73m²)
- Concomitant tamoxifen use
- Pre-existing macular disease 1, 2
Special Populations
Renal Impairment
- Hydroxychloroquine is cleared by the kidneys
- Renal disease increases circulating drug levels and toxicity risk
- Dose reduction recommended in patients with renal insufficiency 1, 2
Pediatric Patients
- Annual retinal screening from start of treatment (rather than waiting 5 years) 2
- Weight-based dosing as for adults
Contraindications
- Hypersensitivity to 4-aminoquinoline compounds
- Pre-existing retinopathy or visual field changes
- Long-term therapy in children (relative contraindication) 2
Precautions
- Use with caution in patients with:
- G6PD deficiency (risk of hemolytic anemia)
- Hepatic disease
- Alcoholism
- Patients taking hepatotoxic drugs 2
- Can cause QT prolongation, especially when combined with other QT-prolonging medications 2
COVID-19 Use
- Not recommended for COVID-19 treatment or prophylaxis based on high-certainty evidence showing no mortality benefit and increased risk of adverse effects 2
Common Pitfalls to Avoid
- Overdosing: Using ideal body weight rather than actual body weight for dose calculations can lead to overdosage in thin individuals 1
- Inadequate monitoring: Failure to conduct baseline and regular ophthalmologic examinations 2
- Ignoring renal function: Not adjusting dose in patients with renal impairment 1, 2
- Prolonged use without monitoring: Risk increases significantly after 5 years of use, even at recommended doses 1
- Overlooking drug interactions: Particularly with QT-prolonging medications 2
By following these evidence-based guidelines for hydroxychloroquine dosing and monitoring, clinicians can maximize therapeutic benefits while minimizing the risk of serious adverse effects, particularly retinal toxicity.