Treatment of interstitial cystitis with a quercetin supplement.

PURPOSE

Interstitial cystitis (IC) is a disorder of unknown etiology with few effective therapies. Oral bioflavonoid therapy utilizing quercetin recently proved to be clinically effective in men with chronic pelvic pain syndrome, a disorder with similarities to IC. We therefore tested in an open-label trial a quercetin-based supplement in patients with clinically proven IC.

MATERIALS AND METHODS

Twenty-two patients (5 men and 17 women; average age 53.1 years) with classically documented IC received one capsule of Cysta-Q complex (equivalent to 500 mg of quercetin) twice a day for 4 weeks. Symptoms were assessed before and after therapy by the IC problem and symptom indices as well as by global assessment of pain (range 0-10).

RESULTS

Two patients did not complete the study. In the remaining 20 patients, improvement was seen in all three parameters tested. After 4 weeks of treatment, the mean (+/- SEM) problem index improved from 11.3 +/- 0.6 to 5.1 +/- 0.7 (p = .000001), the mean symptom index improved from 11.9 +/- 0.9 to 4.5 +/- 0.5 (p = .000001), and the mean global assessment score improved from 8.2 +/- 0.4 to 3.5 +/- 0.4 (p = .000001). None of the patients experienced any negative side effects, and all but one patient had at least some improvement in every outcome measure.

CONCLUSION

Oral therapy with the quercetin supplement Cysta-Q was well tolerated and provided significant symptomatic improvement in patients with IC. Larger, randomized, placebo-controlled trials appear warranted based on these preliminary open-label results.