The effects of capsaicin on the neurogenic hyperreflexic detrusor. A double blind placebo controlled study in patients with spinal cord disease. Preliminary results.

Purpose: Several recent open studies have provided encouraging results as to the efficacy of intravesical installations of capsaicin for neurogenic hyperreflectivity. The present trial was performed to verify these results under controlled conditions. Intravesical installation of capsaicin represents a new therapeutic hope for the treatment of the neurogenic hyperrelfexic bladder.

Method: This randomized, double-blind study compared the results of the intravesical installation of 30 mg capsaicin in 100 ml of 30% alcohol (experimental group) with those of installing 100 ml 30% alcohol alone (control group). On day 0 and day 30, urodynamic and biopsic examinations were performed in all subjects of each group.

Patients: All the subjects included in the study had a functionally disabling form of neurogenic hyperreflexic bladder resistant to the usual therapies. Cystoscopy and retrograde cystography were performed to exclude any patient who presented with a tumor-like lesion or had vesicoureteral reflux.

Results: Twelve paraplegic of tetraplegic subjects, seven women and five men whose average age was 46, were included. Eight had multiple sclerosis, and four had sustained a traumatic spinal cord injury. The patients were randomly separated into two groups of six. Initially, there was no clinical or urodynamic differences in these groups. Installation immediately triggered side effects and during the first 7 days (suprapubic burning sensation, sensory urgency, hot flushes, autonomic hyperreflexia, hematuria) in five of the six subjects in both groups. Bladder biopsy revealed no significant deterioration. On day 30, there was improvement in all of the experimental-group of patients with significant regression of leakage (P = 0.002) and of sensory urgency (P = 0.01). Only one control subject had amelioration. Urodynamic examination showed a rise in bladder capacity from 172.5 to 312.3 ml in the experimental group, significantly greater (P = 0.03) than the rise from 129 to 175.3 ml observed in the control group.

Conclusion: This trial fully confirms the efficacy of intravesical installations of capsaicin, an efficacy obtained at the cost of nonnegligible side effects. An intermediate-term follow-up of this treatment will be necessary before considering more widespread use of this agent.