DIMETHYL-SULFOXIDE DOES NOT TRIGGER URINE HISTAMINE-RELEASE IN INTERSTITIAL CYSTITIS

Objectives. Dimethyl sulfoxide (DMSO), an agent that provides symptoma tic relief in patients with interstitial cystitis (IC) works via an un known mechanism. We investigated whether DMSO acts as a chemical stimu lant of mast cell degranulation. Methods. A radioimmunoassay (RIA) spe cific for histamine was used to test this hypothesis. Twelve women wit h strictly diagnosed IC were treated with intravesical instillations o f DMSO. Treatments were repeated at varying intervals, and each patien t received three to six treatments. Urine histamine levels were measur ed before and after each intravesical instillation of DMSO. Dilutional effects of DMSO were corrected for by conversion of urine histamine c oncentration to urine histamine:creatinine ratio. Results. The RIA was unaffected by the addition of DMSO to urine. No consistent change in the urine histamine:creatinine ratio following DMSO instillation was f ound. Trend analysis revealed no trend in the histamine:creatinine rat io with time. Conclusions. The relief of symptoms reported in 50% to 7 7% of patients treated with intravesical DMSO is not related to detect able mast cell release of histamine. Other mechanisms of action must b e investigated to explain the beneficial effect of this agent.