α1-adrenergic blocking agents safe and effective in the treatment of BPH.
Act by relaxing prostate smooth muscle
Terazosin (Hytrin), doxazosin (Cardura), and tamsulosin (Flomax) alfuzosin (Uroxatral).
Most common side effects include headache, dizziness, asthenia, and drowsiness.
May be associated with retrograde ejaculation.
Terazosin and doxazosin have higher likelihood of orthostasis hypotension than other alpha-1 adrenergic blocking agents.
Alpha-1 adrenergic antagonists additional adverse effects include nasal congestion, edema, palpitations erectile dysfunction and fatigue.
Initially developed as antihypertensive agents.
They work by blocking sympathetic adrenergic-receptor-mediated contraction of the prosthetic smooth muscle cells and bladder neck.
Approved agents include alfuzosin, doxazosin, tamsulosin, terzosin, and silodosin.
Alpha blockers are divided on the basis of their degree of selectivity for the alpha-1-receptor subtype.
Terzosin, doxazosin , and alfuzosin are nonselective, blocking alpha-1 receptor subtypes equally.
The wide distribution of alpha-1 receptors in vascular and CNS tissues explains common side effects of alpha-1 receptor blockers which are hypotension, fatigue, and dizziness.
Tamsulosin and silodosin block alpha1b adrenergic receptors and are selective for alpha1 subtype.
In combination with phosphophodiesterase type 5 inhibitors can cause profound hypotension.