Chloroquine and Hydroxychloroquine Toxicity

Abstract

Chloroquine and hydroxychloroquine have been used for decades as antimalarials and also as immunomodulating therapies for rheumatic diseases such as systemic lupus erythematosus and rheumatoid arthritis. They also have antiviral properties and are currently used empirically for the treatment of coronavirus disease 2019 (COVID-19). Retinal toxicity is a potential complication of these medications. Current ophthalmic screening and dosing recommendations aim to decrease the risk of developing retinopathy or prevent its progression. Baseline fundus examination is not currently recommended before initiating chloroquine or hydroxychloroquine for COVID-19 due to presumed very low risk of retinal toxicity. However, doses of the drugs used for the treatment of COVID-19 exceed the recommended doses, and patients often have additional risk factors. Research in the future is warranted to confirm the risk and incidence of toxicity with this novel use.