The effect of duloxetine on urethral sphincter morphology

This was a pilot study to identify whether a course of duloxetine had any effect on urethral sphincter morphology.

Fifteen women with urodynamic stress incontinence were treated with duloxetine. The pretreatment condition of the bladder was assessed with the Patient Global Impression of Severity scale. A transperineal ultrasound scan was performed before therapy and again after 4-8 weeks of treatment. The urethral length and the width of the hypoechogenic core (longitudinal smooth muscle, vascular plexus and urothelium) were assessed.

Baseline incontinence symptoms were moderate or severe in 87% of women and an improvement following treatment was reported in 80% of women. Poor views were obtained of the striated muscle. There was a statistically significant increase in the mean width of the hypoechogenic core of the urethra from 5.0 mm to 6.3 mm (P < 0.01). There was no statistically significant change in the length of the urethra (mean 29.4 mm before and 28.0 mm after treatment).

Duloxetine appears to result in an alteration of the smooth muscle component of the urethral sphincter.