Neurourology

Desensitization of Bladder Sensory Fibers by Intravesical Resiniferatoxin, a Capsaicin Analog: Long-Term Results for the Treatment of Detrusor Hyperreflexia
Carlos Silva^a, Maria-Edite Rio^b, Francisco Cruz<sup>a, c

a</sup>Departments of Urology and
^bNeurology, Hospital S. João and
^cInstitute of Histology and Embryology of the Faculty of Medicine and IBMC of the University of Porto, Porto, Portugal

Address of Corresponding Author

Eur Urol 2000;38:444-452 (DOI: 10.1159/000020322)

  Key Words

• Resiniferatoxin
• Capsaicin
• Bladder
• Detrusor hyperreflexia
• Desensitization

  Abstract

Objectives: To assess the pungency and the desensitizing effects of intravesical resiniferatoxin, an ultrapotent capsaicin analog, in patients with detrusor hyperreflexia.

Methods: Fourteen patients with detrusor hyperreflexia were instilled during 30 min, without any form of local anesthesia, with 100 ml (or the bladder capacity if lower than that volume) of 50 or 100 nM resiniferatoxin solutions in 10% alcohol in saline. Patients were evaluated by voiding chart and urodynamic tests (volume to first contraction, maximal cystometric capacity, maximal detrusor pressure, icewater test) at 14, 30, 60, and 90 days and every 3 months thereafter

Results: Resiniferatoxin instillation did not evoke pain or temporary worsening of urinary symptoms. Treatment improved or abolished incontinence in 9 out of 12 incontinent patients. Mean urinary frequency decreased from 14.2±6.4 to 10.3±3.2 at 3 months (p = 0.01). At this time point, mean maximal cystometric capacity increased from 182.3±119.8 to 330.0±201.6 ml (p = 0.01) and the ice water test, positive in 13 cases, became negative in 8 of them. Maximal detrusor pressure was not modified by the treatment. The effect was long-lasting, reaching 12 months in 7 cases.

Conclusions: The absence of irritative symptoms during bladder instillation of resiniferatoxin and the rapid onset of desensitization make this vanilloid superior to capsaicin for the treatment of detrusor hyperreflexia.

  Author Contacts

Prof. Francisco Cruz
Department of Urology, Hospital de S. João
P-4200 Porto (Portugal)
Tel. +351 2 5091468, Fax +351 2 5505728

  Article Information

Accepted after revision: October 19, 1999
Number of Print Pages : 9
Number of Figures : 5, Number of Tables : 1, Number of References : 28