Electromotive administration of intravesical bethanechol and the clinical impact on acontractile detrusor management: introduction of a new test.

Purpose: It is often difficult to determine the functional status of the detrusor muscle in patients with detrusor areflexia. We performed a clinical study to establish a test defining residual detrusor capacity in such patients.

Materials And Methods: In phase 1, 5 controls with detrusor areflexia were tested with an intravesical instillation of 20 mg. bethanechol in 150 cc of sodium chloride 0.3% with and without 20 mA. of pulsed current applied via an electrode catheter through the saline. Cystometry simultaneously recorded intravesical pressure changes. In phase 2, 45 patients with detrusor areflexia were tested with electromotive administration of intravesical bethanechol. In phase 3, 25 mg. bethanechol given orally once daily were prescribed for 15 patients and voiding control was assessed after 6 weeks of therapy.

Results: Neither bethanechol without current nor current through saline only led to increased intravesical pressure. However, we noted a mean pressure increase of 34 cm. water during the electromotive administration of bethanechol in 24 of 26 patients with areflexia and neurological disease compared to only 3 cm. water in 3 of 11 with a history of chronic bladder dilatation. Oral bethanechol restored spontaneous voiding in 9 of 11 patients who had had a positive response to the electromotive administration of bethanechol, whereas all 4 without a pressure increase during the electromotive administration of bethanechol did not void spontaneously.

Conclusions: Electromotive administration of intravesical bethanechol identifies patients with an atonic bladder and adequate residual detrusor muscle function who are candidates for restorative measures, such as oral bethanechol and intravesical electrostimulation. Those who do not respond to the electromotive administration of bethanechol do not benefit from oral bethanechol and are candidates for catheterization.