Study Finds Blood Levels of Plaquenil may be Important Indicator of Eye Disease Risk
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. The lead author of the study is Lupus Foundation of America 2018 Evelyn V. Hess Award winner, Michelle Petri, M.D., M.P.H. of Johns Hopkins University.
While previous research has also demonstrated that treatment with Plaquenil is associated with development of retinopathy over time, this is the first study to look at how blood levels of the medication may be used to assess a person’s risk of the disease. Monitoring blood values of Plaquenil is already an important intervention to help track and improve a patient’s medication adherence, and these findings suggest a blood test may also help to reduce overdosage, or flag patients at high risk. Learn about protecting your eyesight when taking Plaquenil.