Interstitial cystitis drug can affect the macula in the eye, threaten sight

DEAR DR. ROACH » Could you discuss Elmiron side effects and the pending lawsuit? I have been on this for years for interstitial cystitis and am worried about staying on it even though it is the only relief I found.

— C.H.

ANSWER » “Interstitial cystitis” is a term used for chronic bladder pain when no other cause has been identified. It is not well understood. It appears some protective layers of the bladder are damaged, allowing irritants in the urine to attack deeper layers, causing pain. There may be an autoimmune component to the disease. There does seem to be a family predisposition.

Before considering medication therapy, it’s important to identify individual triggers to symptoms, whether through diet, body position or exercise. Some people do better with more fluid, some with less. Pelvic floor physical therapy can bring great relief to many with IC.

If medication is indicated, amitriptyline is usually the first tried, and is effective for many. It is not effective for all, and pentosan polysulfate (Elmiron) is then often tried. It may take three to six months to see maximum benefit. It appears to work by repairing the damaged protective layers of the bladder. Side effects of nausea and diarrhea happen 10% to 20% of the time. Hair loss may occur and is reversible with stopping the medication. Liver function abnormalities are possible but uncommon.

In 2018, a paper identified damage to the macula (the center of the retina) in people who had been taking the medication for an average of 15 years. A further study in 2019 confirmed people taking pentosan polysulfate may develop pigment in the retina, which threatens sight.

A lawsuit claims that the drug manufacturer withheld knowledge about this potential side effect.

People with IC with vision symptoms should have a visual examination by an ophthalmologist. The risk of retina damage is highest in people who have taken the most Elmiron — 42% of people taking the highest amount of Elmiron for many years had evidence of this toxicity.

There is evidence the damage may continue even after the drug is stopped. People may choose to continue the medication despite this toxicity. Knowing the risks is essential to make an informed decision.

Contact Dr. Roach at ToYourGoodHealth@med. cornell.edu.