Urodynamic changes during therapeutic intravesical instillations of capsaicin

To describe the technique for and urodynamic changes during therapeutic instillations of intravesical capsaicin in patients with detrusor hyper-reflexia.

Ninety intravesical instillations of capsaicin were performed as a therapeutic procedure in 30 patients; 21 patients had various causes of non-traumatic spinal cord disease, five patients were very severely neurologically impaired and were bed-bound with an indwelling catheter, and four were neurologically normal. Simultaneous cystometry was performed in 25 patients during the instillation of capsaicin; 100 mL of 1 or 2 mmol/L capsaicin in 30% ethanol/saline was instilled into the bladder for 30 min and two patients received 30% ethanol/saline only. The last 56 capsaicin treatments were preceded by the instillation of 40 mL of 2% lignocaine for 20 min. Detrusor hyper-reflexia was decreased and urinary continence improved for 3-6 months after a single instillation; the instillation was then repeated. Two patients who received only ethanol/saline showed no clinical or urodynamic improvement.

The treatment was not abandoned in any patient due to discomfort and there were no short- or medium-term complications. All patients with spinal cord disease and phasic detrusor hyper-reflexia had similar, frequent and repetitive detrusor contractions during the instillation of capsaicin. These acute reactive contractions did not occur in the neurologically normal patients. Similarly, the instillation of intravesical lignocaine only caused no phasic detrusor contractions. Intravesical lignocaine instillation before capsaicin markedly reduced and sometimes abolished the detrusor overactivity and lessened the discomfort for the patients. The instillation of lignocaine before capsaicin did not alter the benefit from each instillation of intravesical capsaicin.

A method has been developed for administering capsaicin intravesically which diminishes discomfort for the patient and in the short- and medium-term is free of complications. The study also provides functional evidence of the role of capsaicin-sensitive afferents in phasic detrusor hyper-reflexia due to spinal cord disease.