American Academy of Ophthalmology updateRevised Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy
Section snippets
Chloroquine and Hydroxychloroquine Toxicity
The mechanism of CQ and HCQ toxicity is not well understood. These drugs have acute effects on the metabolism of retinal cells, including the photoreceptors, but it is not clear whether these short-term metabolic effects are the cause of the slow and chronic damage that characterizes the clinical state of toxicity. Both agents bind to melanin in the retinal pigment epithelium (RPE), and this binding may serve to concentrate the agents and contribute to, or prolong, their toxic effects. However,
Risk of Toxicity
Although no one disputes the potential seriousness of retinal toxicity from these drugs, the rationale (cost-effectiveness) for prospective screening depends on the prevalence of toxicity and the ability to prevent adverse clinical effects (Table 1). The risk of toxicity from CQ and HCQ is low, even after many years of use, but there were little prevalence data in older literature. The largest series of rheumatologic patients showed only 1 case of clear toxicity among 1207 users.9 A smaller
Cumulative Dose
Most reported cases of toxicity have occurred in patients using the drug for more than 7 years or with a cumulative dose that exceeds 1000 g HCQ (or 460 g CQ) (Table 1). The number of reported cases of likely toxicity begins to increase sharply after approximately 5 years of use.10 A cumulative dose of 1000 g HCQ is reached in 7 years with a typical daily dose of 400 mg, and a cumulative dose of 460 g CQ is reached in 5 years with a typical daily dose of 250 mg.
Daily Dose
Older literature (and the
Ophthalmologic Examination
A thorough ophthalmologic examination is important for documentation of visual status and ocular findings. Visual acuity should be measured with best correction in place. The corneal epithelium should be examined to detect verticillata. A dilated fundus examination should be performed and the macula assessed for drusen or pigmentary changes that might be confused with toxicity, with attention to the earliest signs of bull's-eye maculopathy. Pigmentation or atrophy in the periphery and the
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Identification of new risk factors for hydroxychloroquine and chloroquine retinopathy in systemic lupus erythematosus patients
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2023, Chemico-Biological InteractionsScreening for toxic retinopathy due to antimalarial drugs in Tunisia
2023, Journal Francais d'OphtalmologieRedox aspects of cytotoxicity and anti-neuroinflammatory profile of chloroquine and hydroxychloroquine in serum-starved BV-2 microglia
2022, Toxicology and Applied PharmacologyCitation Excerpt :Both clinical reports and experimental data have shown the higher toxicity of chloroquine than hydroxychloroquine (Rodriguez-Caruncho and Bielsa Marsol, 2014; Yang et al., 2020; Ruiz-Irastorza et al., 2010; Jover et al., 2012). This can be manifested as an increased risk of ocular toxicity (Easterbrook, 1999; Marmor et al., 2016) and a higher incidence of gastrointestinal adverse effects (Kalia and Dutz, 2007) in the patients treated with CQ compared to HCQ. In addition, a recent report showed that compared to CQ, HCQ exerted less cytotoxicity in six cell types except for Hep3B and Vero cells monitored by IncuCyte S3 (Yang et al., 2020).
Manuscript no. 2010-451.
Financial Disclosure(s): The author(s) have made the following disclosure(s) for the years 2009 and 2010: Michael Marmor, consultant/advisor, CoMentis, Inc., Eli Lilly and Co., Merck & Co., Inc., Basilea Pharmaceutica, Bayer Corp USA, Johnson & Johnson. Ulrich Kellner, none. Timothy Y. Y. Lai, consultant/advisor, grant support, Novartis Pharmaceuticals; Jonathan S. Lyons, none. William F. Mieler, consultant/advisor, Alcon Laboratories, Allergan, Inc., Genentech, Inc.
Correspondence: Flora Lum, MD, American Academy of Ophthalmology, Department of Quality of Care and Knowledge Base Development, 655 Beach Street, San Francisco, CA 94109-1336. E-mail: [email protected].