Highly Accelerated Onset of Hydroxychloroquine Macular Retinopathy

Hydroxychloroquine (HCQ, Plaquenil) is often prescribed in lieu of other sulfate antimalarials to treat rheumatologic diseases because of its pharmacologic efficacy and few reported side effects. However, a known potential side effect of HCQ is retinal toxicity.

A 61-year-old black female presented for screening of ophthalmic disease 2 months after initiation of HCQ for the treatment of polyarthralgia with a positive rheumatoid factor. At the time of the examination, she had taken a cumulative total of 19.8 g of HCQ and was found to have bilateral bull's-eye retinopathy. The patient had no known risk factors for HCQ toxicity. HCQ was discontinued, and the patient was prescribed ibuprofen for her polyarthralgia symptoms. The ophthalmic effects of HCQ toxicity were permanent.

Known major risk factors for HCQ retinal toxicity include drug loads >300 mg/day (5 mg/kg/day), use for >5 years, a cumulative dose >1,000 g, underlying retinal disease or retinopathy, tamoxifen use, and renal disease. Despite not having any of these risk factors and having a reduced drug load during the treatment period, our patient developed the signs and symptoms of HCQ toxicity. This case suggests underlying mechanisms for HCQ toxicity other than those previously reported and a need for additional screening tests to prevent HCQ toxicity.