The effect of cholinergic enhancement during filling cystometry: can edrophonium chloride be used as a provocative test for overactive bladder?

Overactive bladder, a highly prevalent disorder, is suspected of having a low detection rate due to the lack of sensitive diagnostic tools. Recent studies imply the involvement of the cholinergic system in the pathophysiological mechanism underlying overactive bladder. We determined whether in vivo enhancement of cholinergic activity with edrophonium chloride, a potent cholinesterase inhibitor, would serve as a provocative maneuver to increase the sensitivity of filling cystometry.

A total of 27 patients underwent a multichannel video urodynamic evaluation, followed by filling cystometry with the intravenous administration of 10 mg. edrophonium chloride. The response to edrophonium was defined as a significant change in sensation and decreased bladder capacity, the induction or amplification of involuntary detrusor contractions, or significantly decreased detrusor compliance. Findings were compared in responders and nonresponders.

We identified 11 responders and 16 nonresponders. A response was noted in 78% of the patients with the symptomatology of overactive bladder but in none with no specific complaints suggesting bladder overactivity. In 7 of the 12 responders (64%) baseline cystometry was interpreted as normal. In 6 of the 11 responders (54%) uninhibited urinary leakage was observed in response to edrophonium. There were no serious adverse reactions to the drug.

This preliminary study implies that edrophonium may serve as a novel, practical and safe drug for provocative cystometry. By significantly increasing cystometry sensitivity the drug would facilitate the identification of the subset of patients with overactive bladder who are currently classified with sensory urgency.