New research finds that measuring blood levels of the medication hydroxychloroquine (Plaquenil) in people with lupus may be an effective way to predict risk of retinopathy, a disease which results in impaired or complete loss of vision.

The study assessed 537 people with lupus and measured the levels of the drug present in their blood. Based on the test results, the subjects were divided into three groups: low, medium, and high Plaquenil levels. The rate of retinopathy among those with the lowest average levels was just 1.2%, but disease rate jumped to nearly 8% among the group with the highest average blood values.

The researchers observed that higher blood levels of the drug were found in people with a high body mass index (height-to-weight ratio), as well as those over 60 years old and in people who were on the medication for longer periods of time. Those on the medication for 16 to 20 years exhibited the highest rates of the eye disease, occurring in 11.5% of the people. However, incidence dropped slightly after 20 years of use.

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Guidelines have been issued on Hydroxychloroquine monitoring. It remains a very safe drug, but when used for very long periods regular monitoring is a requirement. Please click here for further information.