Alpha-1 Blockers

α1 receptors blockers are used primarily to treat hypertension and BPH (benign prostatic hypertrophy).  The effects are caused by relaxation of venous and arterial blood vessels (α1 blockade).  α1 receptors are also found in the prostate and bladder (α1A). Tamsulosin has selectivity for the α1A receptors and less impact on vascular alpha receptors (α1B) resulting in fewer side effects.

Class Drugs

• Prazosin

• Terazosin

• Doxazosin

• Tamsulosin

• Alfuzosin

Class Mechanism of Action

• Competitively blocks alpha-1 receptors

Class Application

Symptomatic BPH (some as "off-label" indication)

Hypertension (except tamsulosin and alfuzosin)

Class Adverse Effects

• Syncope (1st dose causes exaggerated orthostatic response)

• Dizziness

• Lack of energy

• Orthostatic hypotension

• Hypotension is exaggerated when combined with nitrates or phosphodiesterase inhibitors 

• Retrograde ejaculation

Drug Table

Drug Name	Application	Comments	Image
Prazosin	Hypertension	PTSD and Nightmares - "off-label" use	"Praying" and "Sin"
Terazosin	Benign Prostatic Hypertrophy; Hypertension		"Tear in Paper " and "Sin"
Doxazosin	Benign Prostatic Hypertrophy; Hypertension		"Doxin dog"
Tamsulosin	Benign Prostatic Hypertrophy; Ureteral Stones; Bladder Outlet Obstruction		"Tammy" and "Sin"
Alfuzosin	Benign Prostatic Hypertrophy		"Elf" and "Sin"