- The primary determinants of risk of retinopathy with use of Chloroquine (CQ) and Hydroxychloroquine (HCQ) :
- Dose (≤5.0 mg/kg/day)
- Weight (real patient weight)
- Duration of treatment1
- There is a risk of retinal toxicity after long-term use. At the AAO*’s recommended dose of ≤5.0 mg/kg/day(real weight), patients have less than 1% risk in the first 5 years of therapy and less than 2% up to 10 years. The risk increases to 20% after 20 years. Risks are much greater with higher doses.2
- The proposed doses to treat COVID-19 are actually 4-5 greater but used very briefly. Based on Marmor et al.’s recent article, extreme doses of CQ/HCQ do accelerate retinal damage, but more probable after many months rather than days.1
- If these drugs are suggest to be used for >1 year, annual screening should be considered.1
- Retinopathy is not of serious concern regarding CQ/HCQ usage during the pandemic, but as new treatment protocols emerge, risk of retinopathy should still be carefully studied.1
This data mainly comes from the analysis of the article by “COVID-19 and Chloroquine/Hydroxychloroquine: Is There Ophthalmological Concern?” by Marmor et al, that analyzes the risk of retinal toxicity in light of its usage during the pandemic.
Sources:
- Marmor, M. F. (2020). COVID-19 and Chloroquine/Hydroxychloroquine: Is There Ophthalmological Concern? American Journal of Ophthalmology. doi: 10.1016/j.ajo.2020.03.029
- Marmor, M. F., Kellner, U., Lai, T. Y., Melles, R. B., & Mieler, W. F. (2016). Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy (2016 Revision).Ophthalmology, 123(6), 1386–1394. doi: 10.1016/j.ophtha.2016.01.058
*AAO = American Academy of Ophthalmology