Oral cimetidine gives effective symptom relief in painful bladder disease:a prospective, randomized, double-blind placebo-controlled trial

Objective To evaluate the efficacy of oral cimetidine as a treatment for pa inful bladder disease (PBD, variously described as a 'symptom complex' of s uprapubic pain, frequency, dysuria and nocturia in the absence of overt uri ne infection) by assessing symptom relief and histological changes in the b ladder wall tissue components, compared with placebo. Patients and methods The study comprised 36 patients with PBD enrolled into a double-blind clinical study with two treatment arms, i.e. oral cimetidin e or placebo, for a 3-month trial. Patients were asked to complete a sympto m questionnaire (maximum score 35), and underwent cystoscopy and bladder bi opsy before treatment allocation. On completing treatment the patients were re-evaluated by the questionnaire and biopsy. The symptom scores and bladd er mucosal histology were compared before and after treatment, and the resu lts analysed statistically to assess the efficacy of cimetidine. Results Of the 36 patients recruited, 34 (94%) completed the study. Those r eceiving cimetidine had a significant improvement in symptoms, with median symptom scores decreasing from 19 to 11 (P < 0.001). Suprapubic pain and no cturia decreased markedly (P = 0.009 and 0.006, respectively). However, his tologically the bladder mucosa showed no qualitative change in the glycosam inoglycan layer or basement membrane, or in muscle collagen deposition, in either group. The T cell infiltrate was marginally decreased in the cimetid ine group (median 203 before and 193 after) and increased in the placebo gr oup (median 243 and 250, P > 0.3 and > 0.2, respectively). Angiogenesis rem ained relatively unchanged. The incidence of mast cells and B cells was spo radic in both groups. Conclusions Oral cimetidine is very effective in relieving symptoms in pati ents with PBD but there is no apparent histological change in the bladder m ucosa after treatment; the mechanism of symptom relief remains to be elucid ated.