This study will investigate if citalopram, a selective serotonin reuptake inhibitor, is reducing the opening pressure of the urethra and possibly causing or worsening stress urinary incontinence. Theoretically, citalopram can affect the tone of urethra through actions on serotonergic receptors in Onuf´s nucleus that innervates the striated muscle in urethra. Treatment with selective serotonin reuptake inhibitors is common and has been associated with urinary incontinence. Stress urinary incontinence is frequent and the most common cause of urinary incontinence. Reboxetine, a norepinephrine reuptake inhibitor, is known to increase urethral opening pressure through actions on adrenoceptors in Onuf´s nucleus and will act as an active control. Should the tone of urethra decrease significantly after ingestion of citalopram, this study would contribute to a deeper understanding of stress urinary incontinence and give rise to a debate of pharmacologic treatment of stress urinary incontinence diagnosed in patients treated with citalopram (this debate may also include use of selective serotonin reuptake inhibitor).~Furthermore, this study is performed to explore the effects of reboxetine and citalopram on the opening pressure of the anal canal. Onuf´s nucleus, like the striated urethral sphincter, innervates the striated skeletal muscle of the external sphincter in the anal canal. The prevalence of fecal incontinence (FI) increases with age and is estimated to affect 15% of people aged over 50 years. Pharmacologic treatment of fecal incontinence is very sparse and new treatments it is very desirable. If reboxetine or citalopram increases the anal opening pressure these pharmacologic agents might leads to new ways of treating FI, making this study the first to explore this area.~The design is a single center, randomized, double-blind, placebo controlled, three period cross over phase I study. Twenty-four healthy, female subjects are recruited and investigated during three independent trial days where one of the pharmacologic agents is given each trial day (citalopram, reboxetine or placebo) in concordance with the sequence (order of the pharmacologic agents given). Subjects will be drafted randomly and evenly among the three sequences possible. During all trial days pressures of the urethra and the anal canal of every subject will be measured by urethral pressure reflectometry and anal acoustic reflectometry at the time of maximum plasma concentration of citalopram and reboxetine. A clinically meaningful difference in urethral pressure after administration of citalopram is assessed to be 10 cmH2O compared to placebo (reboxetine acts as an active control) while a clinically meaningful difference in anal pressure after administration of citalopram or reboxetine is assessed to be 15 cmH2O compared to placebo.
This study will investigate if citalopram, a selective serotonin reuptake inhibitor, is reducing the opening pressure of the urethra and possibly causing or worsening stress urinary incontinence. Reboxetine, a norepinephrine reuptake inhibitor, is known to increase urethral opening pressure through actions on adrenoceptors in Onuf´s nucleus and will act as an active control.~Furthermore, this study is performed to explore the effects of reboxetine and citalopram on the opening pressure of the anal canal.