From the Guidelines
Hydroxychloroquine (HCQ) should be used with caution and under strict guidelines for various medical conditions, prioritizing its benefits against potential risks such as retinal toxicity, especially in long-term use or higher doses, as emphasized by recent studies 1.
Guidelines for Use
The use of HCQ is recommended for autoimmune conditions like rheumatoid arthritis and systemic lupus erythematosus (SLE), with typical dosages ranging from 200-400 mg daily, depending on disease severity and patient response 1. For malaria prevention, the recommended dosage is 400 mg once weekly, starting 1-2 weeks before travel to endemic areas and continuing for 4 weeks after leaving these areas 1.
Monitoring and Safety
Patients on HCQ, especially those on long-term therapy or higher doses, should be monitored for retinal toxicity with baseline and periodic eye exams 1. The medication requires dose adjustment in patients with renal impairment and should be used cautiously in those with heart conditions due to potential QT interval prolongation.
Efficacy and Side Effects
HCQ works by interfering with lysosomal activity and autophagy in immune cells, reducing inflammation in autoimmune conditions, and disrupting parasite metabolism in malaria 1. Common side effects include gastrointestinal disturbances, skin rashes, and headaches, which are usually mild and transient.
Recent Findings and Recommendations
Recent studies have highlighted the importance of balancing the benefits and risks of HCQ, particularly concerning retinal toxicity 1. The European Respiratory Society living guideline update found no mortality benefit of hydroxychloroquine in hospitalized patients with COVID-19 and recommended against its use for this indication 1. Therefore, the use of HCQ should strictly follow established guidelines for approved indications, with careful consideration of potential risks and benefits, as supported by the most recent and highest quality evidence 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION One tablet of 200 mg of hydroxychloroquine sulfate is equivalent to 155 mg base. Malaria Prophylaxis Adults 400 mg (310 mg base) once weekly on the same day of each week starting 2 weeks prior to exposure, and continued for 4 weeks after leaving the endemic area. Lupus Erythematosus The recommended adult dosage is 200 to 400 mg (155 to 310 mg base) daily, administered as a single daily dose or in two divided doses. Rheumatoid Arthritis Initial Adult Dosage 400 mg to 600 mg (310 to 465 mg base) daily, administered as a single daily dose or in two divided doses.
The guidelines for using hydroxychloroquine (HCQ) for various medical conditions are as follows:
- Malaria Prophylaxis: 400 mg (310 mg base) once weekly, starting 2 weeks prior to exposure and continued for 4 weeks after leaving the endemic area 2.
- Lupus Erythematosus: 200 to 400 mg (155 to 310 mg base) daily, administered as a single daily dose or in two divided doses 2.
- Rheumatoid Arthritis:
- Initial dosage: 400 mg to 600 mg (310 to 465 mg base) daily, administered as a single daily dose or in two divided doses.
- Maintenance dosage: 200 mg to 400 mg (155 to 310 mg base) daily, administered as a single daily dose or in two divided doses, after a good response is obtained 2.
From the Research
Guidelines for Using Hydroxychloroquine
The guidelines for using hydroxychloroquine (HCQ) for various medical conditions are as follows:
- HCQ is used as an immunomodulatory and anti-inflammatory agent for the management of autoimmune and rheumatic diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) 3.
- The use of HCQ in patients with SLE and RA requires regular monitoring for potential retinal toxicity, which can be irreversible 4, 5.
- Factors associated with early HCQ-induced retinal toxicity in patients with SLE include lupus anticoagulant positivity and hypercholesterolaemia 5.
- HCQ can also cause hyperpigmentation of the skin and bull's-eye maculopathy in rheumatic patients 6.
- There is no significant association between chronic HCQ use and the incidence of COVID-19, and disease complications are similar in HCQ users and nonusers 7.
Medical Conditions Treated with Hydroxychloroquine
HCQ is used to treat the following medical conditions:
- Systemic lupus erythematosus (SLE) 4, 3, 5, 7
- Rheumatoid arthritis (RA) 4, 3, 6, 7
- COVID-19 (although its efficacy and safety are still uncertain) 3, 7
Potential Side Effects of Hydroxychloroquine
The potential side effects of HCQ include: