I thank Elder et al1 for their contributions in the area of early detection of visual field deficits in patients taking hydroxychloroquine. They noted that “3 of the 4 patients were taking less than 6.5 mg/kg per day.” However, the maximum dosage recommendations of 6.5 mg/kg per day were based on lean body mass, and it appears from the article that lean body mass calculations were not determined for these patients. It would be interesting to know whether these patients truly developed toxic effects within recommended dosing guidelines.
Pautler SE. Hydroxychloroquine Dosages Should Be Calculated Using Lean Body Mass. Arch Ophthalmol. 2007;125(9):1303-1304. doi:10.1001/archopht.125.9.1303-c