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Research Letter
February 2018

Solving the Hydroxychloroquine Dosing Dilemma With a Smartphone App

Author Affiliations
  • 1Rhode Island Eye Institute, Providence
  • 2Section of Ophthalmology, Providence Veterans Affairs Medical Center, Providence, Rhode Island
  • 3Charlotte, Eye, Ear, Nose, and Throat Associates, Charlotte, North Carolina
  • 4Department of Medicine, Newton-Wellesley Hospital, Newton, Massachusetts
  • 5Retina Service, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
JAMA Ophthalmol. 2018;136(2):218-219. doi:10.1001/jamaophthalmol.2017.6076

Hydroxychloroquine retinopathy (HCR) is a potentially blinding disease. Once HCR is detected, there is no treatment and the disease often continues to progress, even when the medication is stopped. Hence, primary prevention by appropriate dosing of hydroxychloroquine offers the best chance of minimizing the risk of HCR.

This strategy remains challenging in practice as up to 56% of patients receive hydroxychloroquine at doses that place them at higher risk for HCR.1 A key reason is disagreement in how to calculate dosages of hydroxychloroquine.2,3 There are 2 methods: one uses ideal body weight (IBW); the other uses actual body weight (ABW). The IBW method assumes that hydroxychloroquine is stored mostly in lean tissue.2 The daily dose must be normalized by lean body mass. This makes the calculation more complicated than the ABW method, which assumes that the drug is distributed evenly in muscle, skin, and fat.3 We describe a free smartphone app—DoseChecker—that can rapidly calculate the optimal weekly dose of hydroxychloroquine using elements of both methods.