Hydroxychloroquine dosing and toxicity: A real-world experience in Saudi Arabia of 63 patients

To assess the ocular toxicity in patients on high doses of hydroxychloroquine (HCQ) per weight, as per the latest American Academy of Ophthalmology (AAO) screening guidelines for HCQ toxicity.

This is a multi-center study looking at consecutive patients attending the ophthalmology clinics at a tertiary hospital and a private clinic in Saudi Arabia. A data collection sheet was used to collect patient's information regarding the dose per body weight, duration of HCQ use and any risk factors associated with the use of the medication as per the latest AAO guidelines for HCQ screening. Ancillary testing including fundus photography, automated visual field (10-2) and spectral domain ocular coherence tomography were done. Further testing with fundus auto-fluorescence and multifocal ERG were done when needed. The presence or absence of toxicity was recorded.

A total of 63 patients were included in the study, 58 females and 5 males. The average patient age was 45 years (range 18-72). The mean dosage of HCQ was 3.9 mg/kg. Fourteen (22%) patients were on doses higher than 5 mg/kg. The duration of treatment ranged from 1-30 years (average 8.3). Thirty six (57%) patients were on the drug for more than 5 years. We found only one (1.58%) patient with HCQ toxic retinopathy over a mean of 8 years treatment period.

A significant number of our patients were found to be on doses of >5 mg/kg of HCQ, which may put them at a higher risk for retinal toxicity. Low dose HCQ such as 100 mg tablets should be made available to help physicians in adjusting the dose as per the latest reported guidelines by the AAO.