What is the comparison between Plaquenil (Hydroxychloroquine) and Hydrochloride?

From the Guidelines

Plaquenil (hydroxychloroquine) is conditionally recommended over other conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) for the treatment of rheumatoid arthritis, particularly for DMARD-naive patients with low disease activity, due to its better tolerability and more favorable risk profile 1.

Key Points

• The typical adult dosage of hydroxychloroquine ranges from 200-400 mg daily, often given as a single daily dose or divided into two doses.
• For rheumatoid arthritis, treatment usually begins with 400-600 mg daily for 4-12 weeks, then reduced to a maintenance dose of 200-400 mg daily.
• For lupus, similar dosing is used.
• For malaria prevention, 400 mg is taken once weekly, starting 1-2 weeks before travel to endemic areas and continuing for 4 weeks after leaving.
• Side effects may include gastrointestinal disturbances, skin rashes, and rarely, retinal toxicity with long-term use.
• Regular eye examinations are recommended for patients on long-term therapy, typically every 6-12 months, to monitor for retinal toxicity 1.

Considerations

• The medication works by interfering with lysosomal activity and autophagy, reducing inflammation in autoimmune conditions and disrupting parasite growth in malaria.
• Hydroxychloroquine should be taken with food to reduce stomach upset, and patients should report any visual changes immediately to their healthcare provider.
• The risk of retinal toxicity is highly dependent on the daily dose by weight, and lower risk is achieved with doses ≤ 5 mg/kg real weight 1.
• Patients of Asian heritage typically show early damage in a more peripheral pattern and have a lower risk of toxicity.

From the Research

Plaquenil (Hydroxychloroquine) Overview

• Plaquenil, also known as hydroxychloroquine, is an antimalarial drug being tested as a potential treatment for COVID-19 2.
• It may serve as a potential prophylactic agent, especially in those at high risk, such as healthcare workers, household contacts of infected patients, and the immunocompromised 2.

Dosage and Administration

• To maintain weekly troughs above the half maximal effective concentration (EC50) in more than 50% of subjects at steady-state in a pre-exposure prophylaxis setting, an 800 mg loading dose followed by 400 mg twice or three times weekly is required 2.
• In an exposure-driven, post-exposure prophylaxis setting, an 800 mg loading dose followed in 6 hours by 600 mg, then 600 mg daily for 4 more days achieved daily troughs above EC50 in more than 50% of subjects 2.

Safety Profile

• Hydroxychloroquine has been associated with a heterogeneous range of cutaneous and extracutaneous adverse events, including maculopapular and erythematous rash, gastrointestinal symptoms, and headache 3.
• More severe conditions include acute generalized exanthematous pustulosis, drug rash with eosinophilia and systemic symptoms, Stevens-Johnson syndrome/toxic epidermal necrolysis, cardiotoxicity, and retinopathy 3.
• Gastrointestinal side effects were common but mild with the use of hydroxychloroquine, while serious side effects were rare 4.
• The most common side effects were upset stomach or nausea, followed by diarrhea, vomiting, or abdominal pain 4.

Efficacy in COVID-19 Treatment

• Neither hydroxychloroquine nor hydroxychloroquine with azithromycin shortened the clinical course of outpatients with COVID-19, and hydroxychloroquine, but not hydroxychloroquine with azithromycin, had only a modest effect on SARS-CoV-2 viral shedding 5.
• Hydroxychloroquine and hydroxychloroquine with azithromycin are not effective therapies for outpatient treatment of SARS-CoV-2 infection 5.

Dermatologic Adverse Effects

• Hydroxychloroquine is associated with myriad adverse dermatologic effects, most of which are poorly characterized by the literature, with unknown frequencies and risk factors 6.
• The most common dermatologic reactions were drug eruption or rash, cutaneous hyperpigmentation, pruritus, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome or toxic epidermal necrolysis, hair loss, and stomatitis 6.