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Total dose of hydroxychloroquine plays role in ocular toxicity
WAIKOLOA, Hawaii — Hydroxychloroquine is used extensively by rheumatologists and dermatologists and yields little systemic concerns, but ophthalmologists are well aware of the bull’s eye type changes, William F. Mieler, MD, said at Retina 2019.
More commonly, though, with prolonged exposure to the drug, fundus examination shows profound pigmentary changes, atrophy and pallor.
“So it goes far beyond the bull’s eye type change,” Mieler said. “You can see worsening months and years after the medication has been discontinued. So recognize that if you see changes from hydroxychloroquine, it’s imperative to stop the medication because this can worsen as time goes by.”
There is no one test to screen for hydroxychloroquine toxicity, but rather a multimodal imaging approach is used to detect abnormalities before vision loss is irreversible, he said.
Most reports of toxicity have occurred in patients using the drug for more than 7 years or more than a 460 g total dose, he said. Dose-dependent duration of exposure play into the rate of potential progression to toxicity.
At a daily dose of 400 mg, the 460 g total dose is generally reached in 5 years.
“I’ve seen patients who have been on medication for less than a year and a half on high-dose [hydroxychloroquine] who become toxic more quickly,” Mieler said.
The dose, now recommended to be less than 5 mg/kg, is based on true body weight rather than ideal body weight, Mieler said. – by Patricia Nale, ELS
Reference: Mieler WF. Systemic therapeutic medications and retinal toxicity. Presented at: Retina 2019; Jan. 20-25, 2019; Waikoloa, Hawaii.
Disclosure: Mieler reports no relevant financial disclosures.