Hydroxychloroquine (Plaquenil) Dosing Calculator

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.