Alpha Blockers

Last updated 23.02.13

 

Index

 

Definitions

-  Anatgonists of alpha adrenergic receptors

-  Selective: Alpha 1 or Alpha 2

-  Nonselective

 

Features

-  Alpha 1 antagonism: vasodilation +

-  Alpha 1a antagonism

-   Smooth muscle relaxation: prostate, urethra, bladder neck..

-   Decreased prostatic hypertrophy

 

Indications

-  HTN: 3rd line agents

-  Raynauds Disease

-  BPH

-  Improvement in IPSS by up to 40%

-  No reduction in long term risk of urinary retention

-  Urolithiaisis

 

Side Effects

-  Postural hypotension (esp Prazosin)

-  Dizziness, fatigue

-  Headaches, nasal congestion

-  Pheochromocytoma (Phenoxybenzamine): Sx preparation

 

Drugs

-  Selective

-  Alpha 1: vasodilation

-   Doxazosin (Long acting)

-   Prazosin (Minipress) (Short acting)

-   Terazosin (Hytrin) (Long Acting)

-   Alpha 1a

-   Tamsulosin (Flomaxtra) (Long Acting)

-  Alpha 2: not used clinically

-  Non-selective

-  Alpha & Beta Blockers: Cervedilol & Labetolol

-  Phenoxybenzamine (irreversible antagonist)