Clinical and urodynamic effects of intravesical capsaicin treatment in patients with chronic traumatic spinal detrusor hyperreflexia.

Abstract

We administered capsaicin, a neurotoxic substance causing a reversible suppression of C fiber afferent neuronal activity, in an attempt to decrease bladder hyperreflexia. Capsaicin solution (2 mM.) dissolved in 30% alcohol was instilled into the bladders of 10 men with traumatic chronic spinal lesions and left in place for 30 minutes. Effects on bladder function, including response to cold stimulation, were recorded during treatment, immediately after instillation and at followup. Bladder function improved in all but 1 patient, which was expressed as an increase in cystometric capacity and/or a decrease in maximal detrusor pressure. The effects lasted for 2 to 7 months. Immediately after capsaicin administration the ice water test was negative in half of the patients. The positive effects on bladder function of capsaicin treatment can be explained by the blocking of C fiber afferents. The optimum dose and treatment interval are presently not established. The ice water test might possibly be used as an instrument to monitor the ideal dosage.