Elmiron® is the sole US FDA-approved pharmacotherapy available for the treatment interstitial cystitis – a condition that causes chronic bladder and pelvic pain. However, new research, presented at the 123rd Annual Meeting of the American Academy of Ophthalmology (12—15 October 2019, CA, USA), demonstrates that significant exposure to Elmiron may be associated with severe retinal damage, which can contribute to vision loss.
An estimated 1 million individuals have interstitial cystitis in the USA. For decades, Elmiron has been the treatment of choice for bladder pain associated with the condition; hundreds of thousands of individuals have thus likely been exposed to the drug.
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In 2018, six patients at the Emory Eye Center (GA, USA) were reported to have developed unusual alterations to their macula – a central part of the retina. The patients had nothing in their medical histories or test results to suggest why they would have developed these retinal abnormalities, however, all had been taking Elmiron for over 15 years.
In light of this, three Kaiser Permanente (CA, USA) ophthalmologists analyzed the company’s extensive database concerning 4.3 million patients to further evaluate the association between Elmiron exposure and retinal damage.
Researchers identified 140 patients eligible for study inclusion: all had taken a mean 5000 Elmiron tablets over the course of 15 years. 91 patients consented to study participation and further examination.
Of the 91 study participants, 22 displayed clear signs of drug-induced retinal abnormalities, as determined by retinal imaging.
Patients' severity of retinal damage increased in tandem with drug dose: 11% of patients who took 500—1000mg of Elmiron displayed definite retinal abnormalities compared with 42% of patients who took more than 1500mg of Elmiron.
Robin Vora, contributing study author and ophthalmologist at Kaise Permanente, commented: “It’s unfortunate. You have a patient with a chronic condition like interstitial cystitis, for which there is no cure and no effective treatment. They get put on these medications because it’s thought to have few side effects and few risks, and no one thinks about it again. And year after year, the number of pills they’re taking goes up and up.”
Vora recommends that, because it is not clear exactly how much of the drug may be toxic, patients who are taking Elmiron should receive annual retinal screening as, if caught early, vision damage can be mitigated.
Interstitial cystitis is poorly understood condition that causes intense pelvic and bladder pain as well as urinating difficulties - the condition is also sometimes referred to as 'painful bladder syndrome' or 'bladder pain syndrome'.
Elmiron is thought to work by forming a protective bladder layer/barrier that prevents irritants in urine aggravating the bladder walls. Elmiron is also a week blood thinning agent.
The retina is the light-sensing layer of the eye. It is a laminated layer of rod and cones cells that transduce light into electrical signals, which are relayed through the optic nerve into the brain.