Capsaicin-induced recovery of voiding in patients with idiopathic non-neurological chronic urinary retention

The therapy of idiopathic non-obstructive non-neurological chronic urinary retention remains unsatisfactory notwithstanding that recently the selective S3 root neural stimulation has been demonstrated to be a promising treatment modality in a selected group of patients. On the basis of our previous experiences we decided to test the hypothesis to use low dosage of intravesical capsaicin to obtain the recovery of voiding in patients with chronic idiopathic non-neurological urinary retention. Nine patients, who presented with a chronic urinary retention for a period longer than 1 year, underwent, during filling cystometrogram, intravesical instillation of 30 ml or a saline solution containing 10^-5M capsaicin (Sigma), at a volume 300 ml, as a provocative test to produce a contractile response. After this test they received 50 ml of a saline solution containing 10^-5M of capsaicin twice weekly for a month. Voiding pattern and urine residue were evaluated at the end of the study, and an urodynamic assessment was performed after 60 days. Intravesical capsaicin, used as a provocative test, produced a reflex contractile activity of the smooth muscle of the bladder at 300 ml of filling and a reduction of bladder capacity in five patients. At 60-day follow-up six patients reported an improvement of their urinary symptoms. Three patients, who previously partially emptied their bladder and two, who used the clean intermittent catheterization, voided spontaneously. Urine residue was significantly reduced from 237.5 ml±54.39 to 61.66±46.22 (p