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Annual eye examinations are recommended for people who take Elmiron for a long period of time. Getty Images
  • Researchers say the bladder medication Elmiron may be damaging the retina of people who take the drug over a long period of time.
  • Elmiron is the only drug approved by the Food and Drug Administration to treat interstitial cystitis.
  • Experts say people taking Elmiron should have eye exams every year.

A widely used drug for a bladder condition has possibly been damaging people’s eyes for decades without anyone’s knowledge.

Reports first surfaced last year that Elmiron, which is prescribed for interstitial cystitis, can be toxic to the retina.

This past weekend, researchers presented more evidence of Elmiron’s effects at the annual meeting of the American Academy of Ophthalmology in San Francisco. The study hasn’t been published yet in a peer-reviewed journal.

“This is certainly a mix of good and bad news for patients,” Alam Hallan, the director of pharmacy at Guelph General Hospital in Ontario, Canada, told Healthline. “New patients will be monitored more rigorously so this damage can be prevented, but for the ones who have already suffered the side effects, this is going to be a difficult situation.”

Researchers reported that during the past year, three Kaiser ophthalmologists in Northern California reviewed medical records and found about a quarter of people with significant exposure to Elmiron showed noticeable eye damage.

They also found that the toxicity of the medication could masquerade as other known retinal conditions, such as pattern dystrophy or age-related macular degeneration.

“While we understand our body better with each medical discovery, there are still a lot of detail and complexities that are outside our current understanding,” Hallan said. “Those seem to be the case here as well. When we introduce a drug in our body, in many cases it builds up in other areas other than the one we want to target.”

“In this particular case, this medication, while improving the IC system, was also being built in other cells of our body,” Hallan explained. “Since each cell is slightly different in our organs, the retinal cells have some chemicals that are not present in other cells of our bodies. It is this chemical that has been thought to interact with the Elmiron, resulting in the death of these cells.”

Research estimates between 3 million and 8 million women in the United States and between 1 million and 4 million men may have interstitial cystitis.

Elmiron is the only drug approved by the Food and Drug Administration to treat interstitial cystitis. Hundreds of thousands of people have been treated with Elmiron.

In 2018, Dr. Nieraj Jain of Atlanta’s Emory Eye Center reported six people who took Elmiron for about 15 years developed unusual changes in their macula, the retina’s central area that delivers clear and crisp central vision. Nothing else in their histories explained the abnormalities.

That prompted the Kaiser doctors to examine their organization’s entire database of 4.3 million patients. They found 140 who had taken about 5,000 Elmiron pills each over 15 years.

Of those, 91 came in for new examinations. Of them, 22 showed clear signs of drug toxicity. That rate rose with the amount of Elmiron taken, from 11 percent for those taking 500 to 1,000 grams to 42 percent for those taking 1,500 grams or more.

Dr. Ming Wang, the founder of Wang Vision 3D Cataract and LASIK Center in Nashville, Tennessee, told Healthline it’s not unusual to see a side effect go undetected for so long.

He says a typical drug trial can last 2 to 5 years, depending on prior results from initial testing done in laboratories, on animals, and with small groups of people.

Drugs can’t be tested for too long before going to market to give patients an opportunity to access new treatments, and to give manufacturers a chance to start generating profit.

“It is possible that this medication caused minor changes to the retina over a long term that could not be observed in the defined time of the study,” said Wang, who has treated country music legends such as Dolly Parton, Kenny Chesney, and Charlie Daniels.

“Also, the retina may not be monitored during a trial like this, if there wasn’t prior known toxicity to the retina from previous investigations,” Wang said. “The report that showed the link between Elmiron and retina issues indicated that patients affected had been on this drug for 12 to 20 years before diagnosis of a retinal problem.”

This situation isn’t without precedent, says Dr. Alena Reznik, an ophthalmologist and glaucoma specialist at the Southern California Eye Institute at CHA Hollywood Presbyterian Medical Center.

“One example of systemic therapy which may cause significant ocular side effects is Plaquenil, a medication frequently used to treat rheumatologic conditions such as rheumatoid arthritis and lupus,” Reznik told Healthline. “Vision loss is rare and cumulative dose-dependent but may be severe and irreversible. We screen any patient who takes Plaquenil at least twice a year with eye exams and ocular testing.”

Doctors behind the latest research are suggesting that people who take Elmiron get their vision checked at least once a year.

If identified early, damage can be mitigated by stopping medication.

Late-stage toxicity can mimic late-stage dry (atrophic) age-related macular degeneration and result in permanent vision loss.

“While this may cause a lot of concern for many patients, it is important to know that the risk is still relatively small,” Hallan said.

“Regular eye examinations need to be done, especially in patients who have already developed some eye issues. Having a history of a particular type of eye disease makes one more vulnerable to these issues. Get those reviewed before starting this medication, as it’s unclear if these side effects can be reversed,” he said.