This is an unprecedented time. It is the dedication of healthcare workers that will lead us through this crisis. Thank you for everything you do.

      Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    Save your unit preferences in settings!

    Hydroxychloroquine (Plaquenil) Dosing Calculator

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



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

    When to Use
    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.
    Confirmed positive
    Confirmed negative


    Please fill out required fields.

    Next Steps
    Creator Insights


    • Doses should be adjusted in conjunction with the prescribing physician to minimize the risk of vision loss and to ensure that the medical risks of medication adjustment are managed.
    • Recommended screening consists of automated visual fields (appropriate to race) and spectral-domain optical coherence tomography (SD-OCT).
    • Other objective testing to be performed as needed or, if available, a multifocal electroretinogram or fundus autofluorescence.
    • Ophthalmoscopy is not a recommended screening tool because photoreceptor damage can be detected by the above techniques before being clinically visible.

    Critical Actions

    If a patient is on a dose that exceeds 5 mg/kg/day of real body weight, the prescribing physician should be contacted to ensure that the dose can be adjusted and medical risks are managed.

    Content Contributors
    About the Creator
    Dr. Ronald B. Melles
    Are you Dr. Ronald B. Melles?
    Content Contributors