Effectiveness of intravesical ozone in interstitial cystitis

Background

Interstitial cystitis, also known as bladder pain syndrome, is a chronic condition marked by pelvic pain, pressure, and persistent urinary urgency and frequency. Many people living with it do not respond well to standard treatments such as oral medications, bladder instillations, or physiotherapy, leaving a gap for alternative approaches. Ozone has known antimicrobial and anti-inflammatory properties in laboratory settings, which led a group of Brazilian researchers to test whether ozone gas delivered directly into the bladder (intravesical ozone) could help patients who had already tried conventional therapy without success.

Study design

Researchers ran a prospective, single-arm, preliminary clinical study involving 16 women with a mean age of 52.9 years, all previously diagnosed with interstitial cystitis or bladder pain syndrome and unresponsive to conventional treatment. Each participant received six applications of intravesical ozone at a concentration of 41 micrograms per millilitre. Symptom severity was tracked using the O'Leary-Sant Interstitial Cystitis Symptom Index and Problem Index (ICSI/ICPI), a validated questionnaire that grades urinary symptoms and their impact on daily life, with follow-up extending to 180 days after treatment.

Findings

Symptom scores fell substantially over the follow-up period. The Symptom Index dropped by 97.5% and the Problem Index by 92.3% at the 180-day mark compared with baseline. The recurrence rate was low, at just 6.25%, and notably no participant in the study was classed as a non-responder - meaning every patient showed some degree of improvement.

What the authors concluded

The authors concluded that intravesical ozone was an effective option for people with treatment-resistant interstitial cystitis and bladder pain syndrome, describing the effect as progressive and safe, at least over the short term studied. They suggested it may offer a useful alternative for patients who have exhausted conventional therapy without relief.

Limitations of this study

This was a small, single-arm study with only 16 participants and no control or placebo comparison group, so the improvements cannot be fully separated from natural symptom fluctuation or a placebo response. It was conducted at a single centre, and follow-up was limited to 180 days, meaning longer-term safety and durability of the effect remain unconfirmed. As the authors themselves describe it as preliminary, larger randomised controlled trials are needed before firm conclusions can be drawn about the effectiveness of intravesical ozone for this condition.