This eye toxicity limits long-term use of the drugs. The risk of toxicity is low for individuals without complicating conditions during the first 5 years of treatment using less than 6.5 mg/kg/day of hydroxychloroquine or 3 mg/kg/day of chloroquine, and/or cumulative doses of less than 1000 gram and 460 gram (total dose), respectively. Hydroxychloroquine sulfate side effects rheumatoid arthritis G6pd plaquenil Plaquenil dosing by weight Screening frequency can be performed on a five-year basis unless there are heightened risk factors, in which case visual fields should be performed every year. Other useful screening tests are multifocal electroretinogram mfERG and fundus autofluorescence FAF. Marmor MF, Hu J. Effect of disease stage on progression of hydroxychloroquine. Major risk factors for hydroxychloroquine-induced retinopathy include a cumulative dose of more than 1000 g, 3 a daily dose of more than 6.5 mg/kg, 3 duration of treatment longer than five years, 9 development of age-related changes to the eye, 10 pre-existing retinopathy, 7 kidney or liver disease, 4 and concurrent use of tamoxifen. 4 Risk factors for retinopathy normal daily doses range 75-300mg toxicity has been reported with doses of 1200 to 2400 mg/day for 1 to 2 years. Mechanism - Inhibition of retinal enzymes and phototoxicity have been suggested as possible causes of the retinal degeneration. The earliest signs of toxicity include bilateral paracentral visual field changes (best detected with a red test object) and a subtle granular depigmentation of the paracentral RPE. Some physicians suggest that lean body weight is more accurate when calculating daily dosage. Hydroxychloroquine retinopathy risk factors The risk of toxic retinopathy in patients on long-term., Hydroxychloroquine-induced retinopathy in a 57-year-old woman Plaquenil baseline testingHydroxychloroquine cardiotoxicityMedicine reactions between plaquenil and xolairPlaquenil for ra side effectsSigma chemical chloroquine phosphate A large study population permitted detailed analysis of risk factors with sub-group analysis such as risk of retinopathy in different ranges of doses by weight. The overall prevalence of HCQ retinopathy was 7.5%, but this increased to around 20% after 20 years of use for those taking 4.0–5.0 mg/kg ABW/day. Hydroxychloroquine retinopathy Eye. Drug induced maculopathy - EyeWiki. Hydroxychloroquine-induced retinopathy in a 57-year-old.. Our results show that the prevalence of hydroxychloroquine retinopathy is much higher than previously recognized and depends on risk factors such as daily dose, duration of use, and kidney disease. The results also suggest the need to revise the way that dosage is calculated to minimize risk. It is recognized, however, that retinal toxicity is occasionally seen in apparently low-risk individuals, inviting the possibility that there may be genetic or other as yet unrecognized risk factors or alternative causes of retinopathy, as these can be hard to distinguish clinically, especially in early stages. Background/Purpose Hydroxychloroquine HCQ is widely used in the treatment of systemic lupus erythematosus SLE, rheumatoid arthritis RA, and other rheumatic diseases. While generally well-tolerated and regarded as one of the safest treatment options for these conditions, the major long-term risk is vision-threatening retinopathy. The risk of retinopathy has been shown to vary by amount.