Researchers are warning doctors to carefully review medical histories of patients experiencing vision loss and other eye problems, after finding that maculopathy associated with the bladder pain drug Elmiron is easily misdiagnosed.
Their paper, which was published in the American Journal of Opthalmology Case Reports earlier this year, involves a 41-year-old woman who began developing vision problems, including darkening vision, progressive difficulty reading, and a loss of night vision, while taking Elmiron to treat interstitial cystitis.
She was initially diagnosed with Stargardt disease, an inherited form of retinal deterioration that usually appears during childhood and is similar to the pigmentary maculopathy reportedly experienced by some Elmiron patients. However, after a genetic test came back negative, a subsequent review of the patient’s pharmacy records revealed her Elmiron use. Realizing she fit the toxicity profile, the woman’s doctors diagnosed maculopathy related to the long-term use of Elmiron.
“This case highlights the importance of careful review of past medical histories and medication profiles of all patients, particularly those with retinal and imaging findings suggestive of a dystrophic process,” the authors wrote. “Failure to diagnose a medication toxicity in a timely fashion may lead to preventable irreversible vision loss. Furthermore, inappropriate diagnosis of a retinal dystrophy may lead to unwarranted genetic counseling and ill-informed life and family planning.”
The U.S. Food & Drug Administration (FDA) approved Elmiron (pentosan polysulfate sodium) in 1996, and it remains the only agency-approved drug indicated to relieve bladder pain associated with interstitial cystitis. Since then, however, the FDA’s Adverse Event Reporting System (FAERS) has received at least 100 reports of eye disorders related to the use of Elmiron, including 8 cases considered serious and 22 that mentioned various forms of maculopathy.
Those reports prompted the FDA to add Elmiron on its so-called “Watch List” earlier this year. It’s important to note, however, that the listing does not indicate the agency has actually concluded Elmiron causes vision problems, only that a potential risk has been identified.
The FDA will take action — changes to labeling, restricting the drug’s use, or (very rarely) removing it from the market – if its evaluation ultimately confirms an Elmiron safety issue.