Drug repurposing involves identifying new therapeutic uses for existing drugs. Examples include:
Aspirin—Originally created as a pain killer, it was later found to be effective in preventing heart attacks and strokes.
Thalidomide—Developed to treat morning sickness, it was later used as a treatment for multiple myeloma.
Metformin—Initially an anti-diabetic drug, it was reworked as a treatment for cancer and Alzheimer’s disease
Drug repurposing is also being explored for vision diseases. Research at the University of Virginia and at the National Eye Institute at the National Institutes of Health has demonstrated how two drugs, one originally made to treat HIV and another developed for high blood pressure, can be used for vision diseases.
Starting with the University of Virginia, researchers at the lab of Jayakrishna Ambati, MD, founding director of UVA Health’s Center for Advanced Vision Science, found that the HIV drug, lamivudine, can improve vision in patients with diabetic macular edema (DME). This drug can do so more effectively and at a lower cost than most available treatments. In addition, it is taken orally, which allows patients an alternative to monthly eye injections.
Ambati and his collaborators at Brazil’s Universidade Federal de São Paulo studied 24 adults with DME in a small randomized clinical trial. Participants were randomly assigned to either receive lamivudine or a placebo. Four weeks after receiving the drug or placebo, they also began receiving injections of bevacizumab into their eyes.
Those who received lamivudine experienced vision improvements before their first eye injection. Their ability to read letters on an eye chart improved by 9.8 letters or 2 lines on the eye chart at four weeks. In comparison, those who received the placebo saw their ability to read the eye chart decrease by 1.8 letters during that same time period. A month after the bevacizumab injections were administered, those who took lamivudine had improved by 16.9 letters or more than 3 lines on an eye chart. As for the placebo group, when they received bevacizumab, they improved by just 5.3 letters.
Scientists believe that lamivudine is effective against DME because it blocks the activity of inflammasomes. Inflammasomes normally act as sensors of infection, but they have been associated in the development of DME. This study suggests that lamivudine can work alone or in conjunction with bevacizumab injections. Of course, more research is needed to confirm if this is the case. Still, using lamivudine without bevacizumab could help many people who have limited access to specialist or can’t afford the bevacizumab injections.
Future trials with a larger number of patients will be needed to determine how to best utilize lamivudine. Still, the results from this study are encouraging.
Another repurposed drug, reserpine, has been shown in laboratory studies to protect retinal neurons needed for vision. Work done at the National Eye Institute suggests that this drug, which was approved for high blood pressure, might be effective in treating retinitis pigmentosa.
Researchers in the lab of Anand Swaroop, Ph.D., senior investigator at the National Eye Institute tested reserpine in a rat model of a form of retinitis pigmentosa that is caused by a mutation in the visual pigment gene rhodopsin. Compared to untreated rats, reserpine preserved the function of rod photoreceptors, which convert light entering the eye into electrical signals that are sent to the brain.
Interestingly, reserpine protected rod photoreceptors better in female rats than male rats. Scientists aren’t sure why this occurs, and further research is needed to learn about the different levels of protection observed between female and male rats.
Swaroop’s lab is working on more potent reserpine-related drugs to treat late-onset or slowly developing inherited retinal disease or to stall vision loss in aggressive varieties of retinitis pigmentosa, until other treatments are created. While reserpine is no longer used for treating high blood pressure due to its side effects, the dosage needed to treat retinal degeneration is low, and the medicine can be delivered directly in the eye. Reserpine is a small molecule treatment, which makes it easier to administer to targeted tissues in the eye.
While not every drug can be repurposed to treat vision diseases, those that can offer alternatives to patients who have DME, retinitis pigmentosa or other vision diseases. Research once again demonstrates that diseases don’t have the final say, options are available to improve outcomes.
Sources:
https://pmc.ncbi.nlm.nih.gov/articles/PMC12048090/
https://newsroom.uvahealth.com/2025/05/27/drug-improves-sight-for-diabetic-macular-edema-patients/