Antimuscarinic effects on current perception threshold: a prospective placebo control study.
OBJECTIVE
To evaluate the effect of Tolterodine on urethral and bladder afferent nerves in women with detrusor overactivity (DO) in comparison to placebo, by studying the changes in the current perception threshold (CPT).


METHODS
Women with overactive bladder symptoms and idiopathic DO were recruited and randomized in a double-blind manner between placebo and tolterodine extended release. All women underwent CPT testing of the bladder and urethra using a Neurometer constant current stimulator. CPT values were determined at three frequencies, including 2,000 Hz (corresponding to Aβ-fibers), 250 Hz (corresponding to Aδ-fibers), and 5 Hz (corresponding to C fibers) before and 7 days on treatment. CPT values before and on treatment were compared using a Wilcoxon Signed Rank test.


RESULTS
Twenty women (mean age 46 years) were studied. There was no statistical difference between the two groups in terms of age, ethnicity, severity of symptoms and pre-treatment CPT values. Only in the tolterodine group there was a significantly increased CPT value at 5 and 250 Hz upon both urethral and bladder stimulation after 1 week of treatment. When compared with placebo, women taking tolterodine had significantly increased Bladder CPT values at 5 Hz (P-value <0.05). The electrical stimulation with 5 Hz was described as urgency.


CONCLUSIONS
This is a randomized placebo control study evaluating the effect of antimuscarinics on sensory nerve function in women with DO. Our results support the animal studies that antimuscarinics have an effect on sensory function.
Department of Urogynaecology, St. Mary's Hospital, Imperial College, London, United Kingdom. vijayamathi@aol.com
Gopalan
G
Vijaya
G Alessandro
GA
Digesu
Alexandros
A
Derpapas
Caroline
C
Hendricken
Ruwan
R
Fernando
Vik
V
Khullar
D000328:Adult; D000368:Aged; D001559:Benzhydryl Compounds / Q000494:pharmacology / Q000627:therapeutic use*; D003408:Cresols / Q000494:pharmacology / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010465:Perception / Q000187:drug effects / Q000502:physiology*; D010665:Phenylpropanolamine / Q000494:pharmacology / Q000627:therapeutic use*; D011446:Prospective Studies; D000068737:Tolterodine Tartrate; D016896:Treatment Outcome; D014521:Urethra / Q000294:innervation; D001743:Urinary Bladder / Q000294:innervation; D053201:Urinary Bladder, Overactive / Q000188:drug therapy* / Q000503:physiopathology*
D001559:Benzhydryl Compounds; D003408:Cresols; D003692:Delayed-Action Preparations; D018727:Muscarinic Antagonists; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate