Pentosan polysulfate sodium is used for the symptomatic relief of bladder pain or discomfort associated with interstitial cystitis; the drug has been designated an orphan drug by FDA for this use.
In a randomized, blinded, placebo-controlled study in 151 patients (approximately 96% women; mean age of 44 years) with chronic interstitial cystitis, greater than 50% improvement in bladder pain was reported by a greater proportion of patients receiving pentosan polysulfate sodium (100 mg 3 times daily for 3 months) compared with those receiving placebo (38 versus 18%).
Pentosan polysulfate sodium also has been evaluated in a prospectively designed retrospective analysis of data for 2499 patients (approximately 89% women, mean age of 47 years, 23% of patients older than 60 years of age) with chronic interstitial cystitis who received pentosan polysulfate sodium (300 mg daily) in an open-label unblinded manner. Unblinded evaluations were performed every 3 months and included the patient's rating of the overall change in pain (based on a 6-point scale assessing the patient's recollection of the difference between current and baseline pain) and the change from baseline in pain/discomfort score (based on a 3-point scale). Baseline pain/discomfort scores indicated the presence of severe or unbearable, moderate, or mild or no pain in 60, 33, or 7%, respectively, of patients in the original treatment group. By 3 months, 52% of patients had withdrawn from the study or were ineligible for evaluation; 48, 36, or 24% of patients in the original treatment group received pentosan polysulfate sodium for 3 months, 6 months, or 1 year, respectively. At 3 months, 29% of patients in the original treatment group had pain/discomfort scores that were improved by 1 or 2 categories. At 6 months, pain/discomfort scores were improved by 1 or 2 categories in an additional 5% of patients in the original treatment group; after 6 months, the proportion of patients in the original treatment group reporting first onset of pain relief was less than 1.5%. The median patient rating of overall change in pain corresponded to slight improvement at 3 months and moderate improvement at 6 months.
Patients enrolled in both of these studies met National Institutes of Health criteria for interstitial cystitis based on cystoscopic, cytologic, and biopsy findings.