2023 Aug 18. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–.
ABSTRACT
Chloroquine (CQ) is used to prevent and treat malaria and amebiasis, while hydroxychloroquine (HCQ), a less toxic metabolite of chloroquine, is used to treat rheumatic diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA) and Sjogren's syndrome. While generally considered safe, several adverse effects of HCQ and CQ have been reported, gastrointestinal discomfort being the most common. Allergic reactions rarely occur. Even rarer adverse effects include cardiomyopathy, cardiac conduction defects, neuromyotoxicity, cytopenias, and skin hyperpigmentation. Of all adverse effects of HCQ and CQ, ocular adverse effects are clinically most relevant, and will be the focus of this article.
Both medications can cause corneal deposits, posterior subcapsular lens opacity, ciliary body dysfunction, and most important, irregularity in the macular pigmentation in the early phase, a ring of macular pigment dropout in the advanced stage, and peripheral bone spicule formation, vascular attenuation, and optic disc pallor in the end-stage. Ocular symptoms of retinopathy include blurred and partial loss of central vision, side vision, and in the later stage, night vision. Symptoms of corneal deposits include haloes and glare. Clinical research has resulted in precise screening protocols and safe dosing guidelines to prevent ocular toxicity and detect retinal damage at an early stage.