Antimuscarinic effects on current perception threshold: a prospective placebo control study

Area of Science:

• Urology
• Neuroscience
• Pharmacology

Background:

• Detrusor overactivity (DO) is a common condition causing urinary urgency and frequency.
• Current treatments primarily focus on reducing bladder contractions, with less attention to sensory nerve involvement.
• Understanding the role of afferent nerves in DO is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the effect of tolterodine on urethral and bladder afferent nerve sensitivity in women with DO.
• To compare the impact of tolterodine versus placebo on nerve function using current perception threshold (CPT) testing.
• To determine if antimuscarinic agents modulate sensory nerve activity in the lower urinary tract.

Main Methods:

• A randomized, double-blind, placebo-controlled study involving women with idiopathic DO.
• Current Perception Threshold (CPT) testing at 2,000 Hz (Aβ-fibers), 250 Hz (Aδ-fibers), and 5 Hz (C fibers) of the bladder and urethra.
• CPT measurements were taken before and 7 days after treatment initiation with tolterodine extended release or placebo.

Main Results:

• Twenty women were analyzed; groups were comparable in demographics and baseline CPT.
• Tolterodine significantly increased CPT at 5 Hz and 250 Hz for both urethral and bladder stimulation after one week.
• Compared to placebo, tolterodine significantly elevated bladder CPT at 5 Hz, a stimulus associated with urgency.

Conclusions:

• This study provides clinical evidence that antimuscarinic agents, specifically tolterodine, can modulate sensory nerve function in women with DO.
• The findings support previous animal research suggesting antimuscarinics possess neuroactive properties beyond smooth muscle relaxation.
• Targeting afferent nerve pathways may represent a novel therapeutic strategy for managing overactive bladder symptoms.