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    Patent Pending

    Hydroxychloroquine (Plaquenil) Dosing Calculator

    Calculates maximum daily dose of hydroxychloroquine to reduce risk of retinopathy.

    IMPORTANT

    INSTRUCTIONS

    This calculator is for double-checking hydroxychloroquine dosing, and should NOT be used as the primary means for ordering.

    When to Use
    Pearls/Pitfalls
    Why Use

    Use in an outpatient setting for adult patients taking hydroxychloroquine (Plaquenil).

    • The current American Academy of Ophthalmology (AAO) guidelines, published in 2016, recommend a maximum daily hydroxychloroquine dose of ≤5.0 mg/kg of real weight. These guidelines were established to minimize the likelihood of permanent vision loss related to hydroxychloroquine retinopathy. 
    • The 2016 revision was prompted by a study by Melles and Marmor in 2014 which suggested that hydroxychloroquine retinopathy is more common than previously thought. They demonstrated that a daily consumption of 5.0 mg/kg real body weight or less is associated with a low risk for up to 10 years. However, there is significant variability in individuals that develop hydroxychloroquine retinopathy.
    • This study was performed only in adult patients.
    • The American College of Rheumatology updated their guidelines in August 2016 to acknowledge the American Academy of Ophthalmology’s position, but does not specify a preferred dosing regimen.
    • Doses must be adjusted for renal insufficiency.
    • Patients with underlying retinal or macular disease may be at a higher risk for toxicity.
    • Patients who are undergoing tamoxifen therapy for breast cancer have a higher risk for toxicity.
    • An appropriate dose is required to minimize the risk of hydroxychloroquine related retinopathy and to permit long-term use in most patients. 
    • The overall risk of developing hydroxychloroquine retinopathy in patients on long-term therapy is 7.5% with the risk increasing with higher doses and long-term use.
    • Calculation of appropriate dose of hydroxychloroquine can minimize the risk of hydroxychloroquine retinopathy since vision loss is irreversible and there is no therapy to treat the resulting retinopathy.
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    Creator Insights
    Dr. Ronald B. Melles

    About the Creator

    Ronald B. Melles, MD, is an ophthalmologist and researcher at Kaiser Permanente Redwood City Medical Center in Redwood City, California. Dr. Melles has published extensively on hydroxychloroquine retinopathy.

    To view Dr. Ronald B. Melles's publications, visit PubMed

    Are you Dr. Ronald B. Melles? Send us a message to review your photo and bio, and find out how to submit Creator Insights!
    MDCalc loves calculator creators – researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. These are real scientific discoveries about the nature of the human body, which can be invaluable to physicians taking care of patients.
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    Dr. Ronald B. Melles
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