From the Guidelines
Hydroxychloroquine (Plaquenil) should be prescribed according to specific guidelines that vary by condition, with careful consideration of its potential benefits and risks, including retinal toxicity and cardiac arrhythmias, as reported in recent studies 1. For rheumatoid arthritis and systemic lupus erythematosus (SLE), the typical adult dosage is 200-400 mg daily, with a maximum recommended dose of 5 mg/kg of actual body weight per day, as suggested by the kdigo 2024 clinical practice guideline for the management of lupus nephritis 1. Some key points to consider when prescribing hydroxychloroquine include:
- For malaria prophylaxis, adults should take 400 mg once weekly, starting 1-2 weeks before travel and continuing for 4 weeks after leaving the endemic area, as indicated in the study on how to manage adult patients with malaria in the non-endemic setting 1.
- Treatment of acute malaria requires 800 mg initially, followed by 400 mg at 6,24, and 48 hours, as recommended in the same study 1.
- All patients should undergo baseline ophthalmologic examination before starting treatment and regular eye exams during therapy (typically annually after 5 years of use or earlier with risk factors) to monitor for retinal toxicity, as emphasized in the american college of rheumatology, american academy of dermatology, rheumatologic dermatology society, and american academy of ophthalmology 2020 joint statement on hydroxychloroquine use with respect to retinal toxicity 1.
- Complete blood counts and liver function tests should be performed periodically to monitor for potential adverse effects, as suggested in the study on idiopathic inflammatory myopathies: current trends in pathogenesis, clinical features, and up-to-date treatment recommendations 1.
- Hydroxychloroquine works by interfering with lysosomal activity and autophagy, reducing inflammation in autoimmune conditions, and disrupting parasite metabolism in malaria, as reported in the study on the role of adjunctive treatment strategies in covid-19 and a review of international and national clinical guidelines 1.
- The medication should be taken with food to reduce gastrointestinal side effects, and patients should be monitored for rare but serious adverse effects including cardiac arrhythmias, particularly when combined with other QT-prolonging medications, as warned in the study on cancer, immune suppression and coronavirus disease-19 (covid-19): need to manage drug safety (french society for oncology pharmacy [sfpo] guidelines) 1.
From the FDA Drug Label
Hydroxychloroquine sulfate tablets are an antimalarial and antirheumatic indicated for the: Treatment of uncomplicated malaria due to Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax in adult and pediatric patients. Prophylaxis of malaria in geographic areas where chloroquine resistance is not reported in adult and pediatric patients. Treatment of rheumatoid arthritis in adults. Treatment of systemic lupus erythematosus in adults. Treatment of chronic discoid lupus erythematosus in adults.
The guidelines for using Hydroxychloroquine (Plaquenil) in treating various medical conditions are as follows:
- Malaria:
- Prophylaxis: 400 mg once a week for adults, 6.5 mg/kg up to 400 mg once a week for pediatric patients ≥ 31 kg.
- Treatment of uncomplicated malaria: see full prescribing information for complete dosing information.
- Rheumatoid Arthritis:
- Initial dosage: 400 mg to 600 mg daily.
- Chronic dosage: 200 mg once daily or 400 mg once daily (or in two divided doses).
- Systemic Lupus Erythematosus: 200 mg once daily or 400 mg once daily (or in two divided doses).
- Chronic Discoid Lupus Erythematosus: 200 mg once daily or 400 mg once daily (or in two divided doses) 2.
From the Research
Guidelines for Using Hydroxychloroquine
The guidelines for using hydroxychloroquine (HCQ) in treating various medical conditions are as follows:
- HCQ is an antimalarial drug that has been used to treat and prevent malaria, as well as to treat rheumatic diseases such as systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, and primary Sjögren's syndrome 3.
- The mechanism of action of HCQ has not been fully elucidated, but it is thought to affect various cellular and molecular pathways through different mechanisms 3, 4.
- HCQ has been shown to be a disease-improving agent for the treatment of rheumatic diseases, and is generally considered safe, although adverse reactions have been reported 3, 5.
- The use of HCQ in the treatment of COVID-19 is still uncertain, and there is insufficient evidence about its efficacy and safety in this context 6, 7.
- HCQ has been used as an immunomodulatory and anti-inflammatory agent for the management of autoimmune and rheumatic diseases, and its efficacy is linked to inhibiting lysosomal antigen processing, MHC-II antigen presentation, and TLR functions 7.
Dosage and Administration
The dosage and administration of HCQ vary depending on the medical condition being treated:
- For malaria prophylaxis, an 800 mg loading dose followed by 400 mg twice or 3 times weekly is required 6.
- For COVID-19 prophylaxis, an 800 mg loading dose followed by 600 mg daily for 4 more days has been suggested 6.
- For rheumatic diseases, the dosage of HCQ is typically set on a body weight basis, with regular retinal examinations to minimize the risk of ocular adverse reactions 5.
Safety and Efficacy
The safety and efficacy of HCQ have been evaluated in various studies:
- HCQ is generally well-tolerated, although severe life-threatening adverse effects including cardiomyopathy and conduction defects have been reported 7.
- The use of HCQ in pregnancy does not appear to risk harm to the baby, and may be beneficial to the mother with SLE and her child by controlling the SLE disease activity 5.
- HCQ has been shown to improve glycaemia and reduce the risks of type II diabetes mellitus, and may also reduce atherosclerosis and risks of cardiovascular disease in rheumatic patients 5.