Sympathetic (Adrenergic) Blocking Agents Flashcards
Phentolamine (Alpha Blocker): What does it do and is it reversible
Blocks alpha-1 and alpha-2
Reversible
Sympathetic Antagonists Alpha Receptor Blockers : Agents
Phentolamine Phenoxybenzamine Prazosin Tamsulosin Yohimbine
Phenoxybenzamine: Duration, what it blocks, is it reversible
Irreversible
Both alpha receptors
Lasts an extremely long time
Prazosin: Reversibility, what it blocks, what does it dilate
Reversible
Alpha-1 blocker
veno and arterial dilation
Tamsulosin: Use
Blocks Alpha-1A receptors and is useful in treating benign prostatic hypertrophy
Yohimbine: What does it block, what is it used for, what is the effect
Sexual stimulant
Increase in sympathetic outflow
Alpha-2 block
- Increase in NE
Alpha Receptor Blockers: Cardiovascular action: Nonselective blockers
Blockade of vascular alpha-1 receptor of both arterial and venous pressures
Can produce reflex tachycardia
Block of presynaptic alpha-2 receptors
Block of presynaptic alpha-2 receptors: Results
NE release from adrenergic resulting in more cardiac stimulation
Non-selective alpha blockers: Use
Prevent ischemic necrosis after accidental local infiltration of potent alpha agonists
Reverse NE (lower BP)
Diagnosis and treatment of pheochromocytoma
Peripheral vascular diseases (Raynaud’s disease)
Prazosin: Alpha-1 antagonists: Effects
Relaxation of both arterial and venous smooth muscle
- Decrease in BP
- Based from decreased sympathetic outflow
Less tachycardia due to no alpha-2 block
Alpha blockers: adverse effects
Postural hypotension
- venous pooling
- reflex tachycardia
- Nasal congestion
- Miosis
- Nausea, vomiting, GIT pain
- Priapism
Beta blocker: Non-selective antagonists: Agents
Propranolol
- Non-selective
Metoprolol
- Beta-1 antagonist
Beta-1 blockers: Effects
Decrease BP Decrease HR Decrease CO and contractility Decreased renin release bronchoconstriction Decrease IOP
Beta-2 blocker: Effects
Interfere with perfusion during exercise
Effects more primarily on Vasculature
Bronchoconstriction
Decrease IOP
Beta blockers: Uses
Arrhythmias Angina Thyrotoxicosis: Decrease thyroid stimulation of the heart thus decreasing HR Hypertension Glaucoma CHF - Decrease of remodeling
