Study Finds Dose Response Link Between Elmiron and Vision Problems

Providing strong evidence of a cause-effect relationship, the findings of a new study suggest the side effects of Elmiron are more likely to cause vision loss problems among users taking higher doses of the bladder drug.

Elmiron (pentosan polysulfate sodium or PPS) is the only oral medication approved for treatment of interstitial cystitis, more commonly known as “painful bladder syndrome.” It has been on the market since 1996, and is regularly used for years by individuals suffering from bladder or pelvis pain, since there is no known cure for the underlying condition. However, it has recently been discovered this may cause users to suffer severe retina damage and permanent vision problems, including difficulty adapting in dark light, spots or floaters in the vision and complete blindness.

Since the drug makers failed to disclose this risk until a warning label update was issued a few months ago, a growing number of users are now pursuing Elmiron lawsuits, alleging that long-term use of the medication left them with these permanent retinal damage.

The findings of a new study published online this month by the medical journal Retina may provide important evidence that will be used in these lawsuits regarding the causal connection between Elmiron and vision problems.

Researchers from Emory University reported on a 27-item online survey of individuals with interstitial cystitis, which was conducted in November 2018. Researchers sought information on demographics, exposure history, visual function and prior macular diagnoses.

According to the findings, those with the highest rates of Elmiron exposure were more than twice as likely to report symptoms of vision problems like difficulty reading small print, or had a diagnosis of macular degeneration or pigmentary maculopathy.

“In this large sample of individuals with interstitial cystitis, those in the highest PPS exposure category were more likely to have difficulties reading small print and to report a prior diagnosis of macular disease,” the researchers concluded. “Further study of objective measures of visual function in [Elmiron] users is warranted.”

Such findings are indicative of what researchers refer to as a “dose-response relationship”. This suggests the bigger (or longer) the exposure to a drug or substance, the more likely, and often more intense, the side effects. This is usually viewed as strong proof of a cause-and-effect relationship; meaning it is likely the substance or medication is causing the condition, instead of being a coincidence in the numbers.

There are currently about 100 product liability claims pending in the Elmiron litigation. However, as lawyers continue to review and file claims in the coming months and years, it is expected that nearly 1,000 claims may ultimately be filed by former users now left with permanent vision problems.