The Effect of Terazosin on Bladder Function in the Spinal Cord Injured Patient

Abstract

We prospectively studied the effect of terazosin on bladder compliance in 12 spinal cord injured patients. All study patients had demonstrated previously poor compliance despite clean intermittent catheterization and maximum anticholinergic therapy. Patients were started on 5 mg. terazosin nightly for 4 weeks. They were evaluated with a history, physical examination, symptom score, and synchronous cystoscopy and cystometry before, during and after terazosin therapy. Detrusor compliance improved in all patients during the treatment phase. The change in bladder pressure and the safe bladder volume were statistically and clinically significant. Patients also reported fewer episodes of incontinence and dysreflexia. The improvement in compliance and continence suggests that in the spinal cord injured patient terazosin may have an effect on alpha receptors in the detrusor muscle or central effects and that improved compliance is not due to decreased outlet resistance.

Evidence for the presence of α1 adrenoceptor subtypes in the human ureter

“…However, a role of a 1 ARs present in the spinal cord and in£uencing ureteral physiology [Michelotti et al, 2000] cannot be excluded and it remains to be established. In line with this, administration of a 1 AR drugs produces several e¡ects in animals and humans due to the interaction with a 1 ARs localized in the spinal cord; in particular, e¡ects on LUT seem to be mediated by a 1 ARs present in the intermediate cell column at the sacral level [Swierzewski et al, 1994;Chapple, 1996;Ishizuka et al, 1997], that expresses mRNA encoding each a 1 AR subtype, with the rank of potency a 1D AR > a 1A AR ¼ a 1B AR [Sta¡ord Smith et al, 1999].…”

COMBINED USE OF Α-Adrenergic AND MUSCARINIC ANTAGONISTS FOR THE TREATMENT OF VOIDING DYSFUNCTION

“…23 In 12 spinal cord injured patients the α 1A /α 1D selective antagonist terazosin improved bladder compliance and continence, suggesting that terazosin may have an effect on α receptors in the detrusor muscle or spinal cord and improved bladder compliance is not due to decreased outlet resistance. 24 α Receptors may also modulate voiding function at the level of the spinal cord or peripheral ganglia. There appear to be different effects of adrenergic stimulation on the afferent and efferent pathways in micturition.…”

α₁-Adrenoceptors and Bladder Function

“…If such actions are relevant also for the effects of α 1 -AR antagonists in humans, extravesical, possibly spinal, α 1 -ARs may be relevant targets for drugs meant for treatment of LUTS. Swierzewski et al [48]found in patients with spinal cord injury that terazosin treatment increased detrusor compliance and decreased the number of episodes of incontinence and dysreflexia. Even if an effect on α 1 -ARs in the detrusor cannot be excluded, these results may be interpreted to indicate an action on the CNS.…”