Intravesical resiniferatoxin for the treatment of hypersensitive disorder:A randomized placebo controlled study

Purpose: Present therapeutic approaches to control hypersensitive disorder of the lower urinary tract and bladder pain are clinically and scientifical ly unsatisfactory. We performed a randomized placebo controlled study with followup after 1 and 3 months using intravesical resiniferatoxin to treat h ypersensitive disorder and bladder pain. Materials and Methods: We prospectively randomized 18 patients into 2 group s to receive a single dose of 10 nM. resiniferatoxin intravesically (group 1) or a placebo saline solution only (group 2). All patients had at least a 6-month history of frequency, nocturia, urgency and symptoms of pelvic pai n as well as no urinary tract infection within the last 3 months, functiona l disorders of the lower urinary tract, or other vesical or urethral pathol ogy. Pretreatment voiding pattern and pain score were recorded. Patients we re evaluated after 30 days (primary end point) and 3 months (secondary end point). Results: The 2 groups were adequately homogeneous in regard to patient age, sex ratio, disease duration, voiding pattern and pain score. At the primar y end point mean frequency plus or minus standard error of mean was decreas ed from 12.444 +/- 0.70 voids to 7.111 +/- 0.67 and nocturia from 3.777 +/- 0.27 to 1.666 +/- 0.16 (p <0.01). We observed a lesser significant improve ment in mean frequency in group 1 at the secondary end point to 10.444 +/- 0.94 voids (p <0.05). No significant modification was noted in patients ass igned to placebo. Mean pain score significantly decreased in group 1 at the primary end point from 5.555 +/- 0.29 to 2.666 +/- 0.23 (p <0.01) but not at the secondary end point (4.777 +/- 0.66, p >0.05). No statistically sign ificant improvement in mean pain score was observed in placebo group 2. Dur ing resiniferatoxin infusion 4 group 1 patients noticed a light warm or bur ning sensation at the suprapubic and/or urethral level. Conclusions: Intravesical resiniferatoxin may significantly improve the voi ding pattern and pain score in patients with hypersensitive disorder and bl adder pain. Because resiniferatoxin did not cause a significant warm or bur ning sensation at the suprapubic and/or urethral level, it may be considere d a new strategy for treating hypersensitive disorder and bladder pain. How ever, further studies are necessary to confirm our results and define the r esiniferatoxin mechanism of action, dose and necessary treatment schedule.