BERKELEY, CA (UroToday.com) - Ever since Bruce Stewart popularized the use of intravesical dimethylsulfoxide (DMSO) for the treatment of PBS/IC 40 years ago, it has been a valuable tool for healthcare providers treating this frustrating condition. Lately, it seems, fewer and fewer urologists are using DMSO. Whether this is because of fear of side effects, perceived lack of efficacy or inconvenience is not clear.

Rossberger and colleagues from Goteborg, Sweden retrospectively studied 28 patients, 13 with ulcerative and 15 with nonulcerative IC who were treated with a 6 week course of intravesical solution of 50% DMSO. Some went on to monthly maintenance. Four to 28 could not complete the initial course of therapy because of symptom flare. Of the remaining 24 patients, 9 were classified as successful, having varying degrees of improvement and requiring no other treatments for their condition. Both ulcerative and nonulcerative patients showed responses. Almost half of patients had urethral irritation or pain after the first instillation, but these side effects were transitory. In clinical studies with DMSO, changes in the ocular refractive index or the development of lens opacity in humans have not been encountered. Despite this, eye examinations during extended treatment with DMSO are encouraged by some physicians because of experimental animal data.

In total, the number of instillations ranged between 6 and 32 during a period of 6 weeks to 33 months, with a residual treatment effect persisting up to 72 months. While one-third of patients in this study responded to DMSO if looked out from an intent-to-treat perspective, the results are somewhat better in many published series.

The diverse pharmacologic properties of DMSO render it valuable for the treatment of various diseases. DMSO has been reported to have a beneficial effect in the topical treatment of herpes zoster, improves primary amyloidosis of the bladder, gives protection against intestinal mucosal injury, and, based on experimental studies in rats; it is also believed to prevent the development of liver cirrhosis induced by thioacetamide. It reversible crosses membranes without damaging them and is therefore used as a solvent in biological studies and as a vehicle for drug therapy.

The author conclude that intravesical DMSO, given either as a single treatment course or as a maintenance regimen, appears to be a feasible treatment option for both subtypes of IC. It is associated with a reasonably low degree of discomfort, which is acceptable considering the potential benefit of the treatment.

Scandinavian Journal of Urology and Nephrology, 2005; 39:73-77