From the Guidelines
Hydroxychloroquine should be prescribed at a dose of 5 mg/kg/d, with a maximum daily dose of 400 mg, to minimize the risk of retinopathy and other adverse effects, as supported by recent guidelines and studies 1. The recommended dose of hydroxychloroquine is based on actual body weight, with a typical dose range of 200-400 mg daily for adults.
- For long-term therapy, such as for rheumatoid arthritis or systemic lupus erythematosus, the maintenance dose is usually 200-400 mg daily.
- The maximum recommended daily dose is 5 mg/kg of actual body weight.
- In patients with eGFR <30 ml/min per 1.73 m², the dose of hydroxychloroquine should be reduced by 25% 1. It's essential to take hydroxychloroquine with food or milk to reduce stomach irritation.
- Regular monitoring is crucial during long-term therapy, including baseline and periodic eye examinations (every 6-12 months), as the medication can cause retinal toxicity, particularly with higher doses, longer duration of use, or in patients with kidney disease 1.
- Blood tests to monitor complete blood counts and liver function may also be recommended. The medication typically takes 4-12 weeks to show full therapeutic effect for autoimmune conditions, so patience is necessary when starting treatment.
- Recent data suggested that a blood hydroxychloroquine level above 0.6 mg/l may be associated with a lower risk of LN flare 1.
- The frequency of administration is usually once daily, but it can be divided into twice daily in some cases.
- It's also important to consider the potential benefits and harms of hydroxychloroquine use, including the risk of hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency, and to measure G6PD levels before starting treatment, especially in men of African, Asian, or Middle Eastern origin 1.
From the FDA Drug Label
2.2 Dosage for Malaria in Adult and Pediatric Patients ... Prophylaxis ... The recommended prophylaxis dosage is: Adult patients: 400 mg once a week Pediatric patients ≥ 31 kg: 6.5 mg/kg actual body weight (up to 400 mg) once a week
Treatment of Uncomplicated Malaria ... The dosages for the treatment of uncomplicated malaria are: Adult patients: Administer 800 mg initially; subsequently administer 400 mg at 6 hours, 24 hours, and 48 hours after the initial dose (total dosage = 2,000 mg) Pediatric patients ≥ 31 kg: Administer 13 mg/kg (up to 800 mg) initially; subsequently administer 6.5 mg/kg (up to 400 mg) at 6 hours, 24 hours, and 48 hours after the initial dose (total dosage = 31 mg/kg - up to 2,000 mg).
2.3 Dosage for Rheumatoid Arthritis in Adults The recommended dosage is: Initial dosage: 400 mg to 600 mg daily as a single daily dose or two divided doses. Chronic dosage: 200 mg once daily to 400 mg daily, as a single dose or two divided doses.
2.4 Dosage for Systemic Lupus Erythematosus in Adults The recommended dosage is 200 mg given once daily, or 400 mg given once daily or in two divided doses.
2.5 Dosage for Chronic Discoid Lupus Erythematosus in Adults The recommended dosage is 200 mg given once daily, or 400 mg given once daily or in two divided doses.
The dose and frequency of hydroxychloroquine vary depending on the condition being treated:
- Malaria prophylaxis: 400 mg once a week for adults, and 6.5 mg/kg actual body weight (up to 400 mg) once a week for pediatric patients ≥ 31 kg.
- Treatment of uncomplicated malaria:
- Adult patients: 800 mg initially, followed by 400 mg at 6 hours, 24 hours, and 48 hours after the initial dose.
- Pediatric patients ≥ 31 kg: 13 mg/kg (up to 800 mg) initially, followed by 6.5 mg/kg (up to 400 mg) at 6 hours, 24 hours, and 48 hours after the initial dose.
- Rheumatoid arthritis:
- Initial dosage: 400 mg to 600 mg daily as a single daily dose or two divided doses.
- Chronic dosage: 200 mg once daily to 400 mg daily, as a single dose or two divided doses.
- Systemic lupus erythematosus: 200 mg given once daily, or 400 mg given once daily or in two divided doses.
- Chronic discoid lupus erythematosus: 200 mg given once daily, or 400 mg given once daily or in two divided doses 2.
From the Research
Dose and Frequency of Hydroxychloroquine
- The optimal dose and frequency of hydroxychloroquine are still being researched, with different studies suggesting various dosages and treatment durations 3.
- A daily dose of 200-400 mg of hydroxychloroquine for a treatment duration of 5-8 weeks may moderately reduce the risk of COVID-19 with a relatively low risk of adverse events 3.
- The dose-response relationships of hydroxychloroquine are not well understood, and the minimum dose needed for clinical efficacy and the doses that are toxic are not clearly defined 4.
- Hydroxychloroquine has a half-life of around 50 days and interferes with lysosomal activity and autophagy, interacts with membrane stability, and alters signalling pathways and transcriptional activity 4.
Treatment Duration and Efficacy
- A treatment duration of 5-8 weeks with a daily dose of 200-400 mg of hydroxychloroquine may be the most effective intervention for reducing the risk of COVID-19 3.
- The efficacy and safety of hydroxychloroquine at different doses and courses for COVID-19 prevention have been evaluated in several studies, with mixed results 3.
- Hydroxychloroquine has been used to treat several diseases, including rheumatic autoimmune disorders, such as systemic lupus erythematosus, primary Sjögren's syndrome, and rheumatoid arthritis 5.
Safety and Adverse Effects
- Hydroxychloroquine has a relatively low risk of adverse events when used at a daily dose of 200-400 mg for a treatment duration of 5-8 weeks 3.
- The chemical properties of hydroxychloroquine, including its half-life and volume of distribution, may contribute to its clinical efficacy and adverse effects 4.
- The lack of definitions of the minimum dose needed for clinical efficacy and the doses that are toxic pose challenges to clinical practice 4.