The effects of tolterodine on bladder-filling sensations and perception thresholds to intravesical electrical stimulation: method and initial results

To study the effects of the antimuscarinic agent tolterodine on the perception thresholds to intravesical electrical stimulation (IES) and the effects of the drug on subjective bladder sensation during normal filling cystometry in healthy female volunteers. In seven healthy women IES was applied at 2.5 Hz (pulse width 10 ms, protocol 1), 2.5 Hz (pulse width 0.2 ms, protocol 2), and 250 Hz (pulse width 0.2 ms, protocol 3). Sensory perception thresholds were obtained using electric currents in 0.5 mA steps. Afterwards the bladder was filled and the first bladder-filling sensation, first desire to void, strong desire to void and urge to void were recorded. The bladder was then emptied, the volume measured and subjects were checked for residual urine by ultrasonography. The subjects then received 4 mg of tolterodine and the entire protocol was repeated 2 h afterward. The perception thresholds for IES and bladder sensation levels obtained at baseline were compared statistically with the corresponding values after tolterodine. Tolterodine significantly increased perception thresholds to IES for all three protocols (P = 0.027, 0.018 and 0.018, respectively). The drug had no effect on the filling levels for the corresponding bladder sensation. Oral tolterodine significantly increased the perception threshold to IES in healthy women; there was no effect on subjective bladder sensations during cystometry.