Mitomycin C and epirubicin: functional bladder damage in rats after repeat intravesical instillations

PURPOSE: We studied functional damage in the bladder after intravesical administration of mitomycin C or epirubicin in rats. MATERIALS AND METHODS: A total of 40 rats were divided into 4 groups. Rats in 3 groups received intravesical instillations of mitomycin C, epirubicin or saline. Rats in group 4 received no intravesical instillations and served as normal controls. The doses of drugs administered were based on those used for therapeutic purposes. Changes in vesical capacity and bladder wall compliance were determined. Compliance was defined as the change in vesical volume induced by a given change in pressure. RESULTS: Weekly instillations of 1 mg/ml mitomycin C caused a statistically significant decrease in vesical volume and compliance, which persisted 3 weeks after the cessation of therapy. Epirubicin also induced changes in vesical volume and compliance but only that in bladder compliance achieved statistical significance. These changes were not seen in NaCl treated animals or in normal controls. CONCLUSIONS: Repeat intravesical instillations of mitomycin C have a prolonged effect on bladder function that is not seen after saline solution or epirubicin instillation