Related Experiment Video
Updated: Aug 13, 2026

Photoselective Vaporesection of the Prostate via an End-firing Lithium Triborate Crystal Laser
Published on: May 9, 2018
Acute urinary retention secondary to benign prostatic hyperplasia. Effect of alpha-adrenergic blockade
Abstract:
The alpha-adrenergic blocker phenoxybenzamine has been shown to be useful in the treatment of prostatism. To assess the place of phenoxybenzamine in the management of acute retention, 43 patients presenting with acute urinary retention secondary to benign prostatic hyperplasia were catheterized suprapubically. They were then randomized to receive either oral phenoxybenzamine (10 mg b.i.d.; n = 21), or placebo tablets (n = 22). Forty-eight hours later, the bladder of each patient was filled through the catheter with 300 ml sterile saline, the catheter was clamped, and the patient encouraged to void. Only 2 of 21 (10%) patients receiving phenoxybenzamine and 3 of 22 (14%) receiving placebo were able to void satisfactorily (p = NS). In this study phenoxybenzamine had no place in the management of acute retention of urine secondary to benign prostatic hyperplasia.
Related Concept Videos
Adrenergic Receptors: ɑ Subtype
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
Adrenergic Agonists: Direct-Acting Agents
These agents can be classified...
Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers
Antihypertensive Drugs: Action of β1 Blockers

