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Flashcards in Adrenergic Blockers Deck (36)
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1. irreversible alpha blocker; insurmountable blockade, forms covalent bond with receptors
2. non-selective alpha 1 & 2
3. only therapeutic drug that has noncompetitive antagonism
4. graphically will level off (flatten on y axis) rather than move to right on x axis


Reversible alpha blockers

1. Phentolamine (nonselective alpha 1 & alpha 2)
2. Prazosin (alpha 1 selective)
3. Terazosin (alpha 1 selective)
4. Doxazosin (alpha 1 selective)
5. Tamsulosin (alpha 1 selective)
6. Yohimbine (alpha 2 selective)


alpha 1 selective blockers

1. Prazosin
2. Terazosin
3. Doxazosin
4. Tamsulosin (specific alpha 1A antagonist)

These are all REVERSIBLE blockers


alpha 2 selective blockers


this is a REVERSIBLE blocker


Irreversible alpha blocker

phenoxybenzamine; nonselective


CVS effects of alpha blockers

1. decrease PVR & BP

Convert a pressor response of Epi to a depressor response. Called Epinephrine Reversal

Cause orthostatic hypotension & reflex tachycardia, esp with nonselective blockers due to increase release of NE (due to alpha2 blockade)


adverse effects of alpha blockers

Cause orthostatic hypotension & reflex tachycardia, esp with nonselective blockers due to increase release of NE (due to alpha2 blockade)


Effects of alpha blockers on urinary bladder

1. alpha 1 receptors are expressed in base of bladder & prostate & blockade-->decrease resistance to flow or urine--> used to tx urinary symptoms in men with BPH

alpha 1A subtype may be the most important subtype in mediating prostate smooth muscle contraction; Tamsulosin=specific alpha 1A antagonist


specific alpha 1A antagonist


has greater potency than other alpha 1 blockers bc alpha 1A subtype may be the most important subtype in mediating prostate smooth muscle contraction


alpha blockers used to treat pheochromocytoma

phenoxybenzamine & phentolamine


Drugs used to treat hypertension

prazosin (selective alpha1 blocker)


patient presents with decreased heart rate, sweating, malignant hypertension

Dx: pheochromocytoma

increased epi bc tumor-->


alpha blocker used to treat HTN due to clonidine withdrawal, cheese reaction



alpha blocker used to treat peripheral vascular disease & Raynauds

Prazosin (selective alpha1 blocker)


What's causing urinary difficulty in BPH?

in BPH activation of alpha1A receptors in bladder trigone, prostate & prostatic urethra increases smooth muscle tone

blockade of these receptors relaxes the structures--> increases urinary flow rate & allows more complete emptying of bladder.

DO NOT REVESE THE HYPERPLASIA, only provide symptomatic relief!!


Toxicity of alpha blockers

1. orthostatic hypertension
2. reflex tachycardia w nonselective blockers (due to increased NE by alpha2 blockade
**tachycardia is less common with alpha1 selective blockers


1. drugs with partial agonist activity or "intrinsic sympathomimetic activity
2. what is this?

1. pindolol & acebutolol
2. advantage of treating patients with asthma bc the drugs are less likely to cause bronchospasm


1. drugs with local anesthetic activity or 'membrane stabilizing activity
2. what is this?

1. propranolol
2. the result of blockade of Na channels & can be demonstrated experimentally; no clinical effect


longterm use of an agonist has what effect on receptors

down regulation of receptors


longterm use of an antagonist has what effect on receptors

up regulation of receptors


why don't you abruptly stop beta blockers

rebound hypertension


B1 blockers safe for asthmatics

1. Betaxolol
2. Esmolol
3. Atenolol
4. Metoprolol

"a BEAM of beta blockers"


Why is Timolol the preferred beta blocker to treat glaucoma?

when used topically in the eye some beta blockers decrease protective reflexes & increase the risk of corneal ulceration. this is ABSENT in Timolol


beta blocker used to treat pheochromocytoma



side effects of beta blockers

1. bradycardia
2. bronchospasm*
3. chronic use assoc w increased lipid levels (LDL & TG)
4. may mask premonitory symptoms of hypoglycemia (tachycardia, tremor, anxiety)
5. CNS effects: mild sedation, vivid dreams, rarely depression


Why should beta blockers be used cautiously in patients with CHF?

because beta blockers depress myocardial contractility & excitability


premonitory symptoms of hypoglycemia

tachycardia, tremor, anxiety

can be masked by beta blockers


Beta blockers used to treat heart failure

1. metoprolol
2. bisoprolol
3. carvedilol


beta blockers used to treat cardiac arrhythmias & MOA

Sotalol works by increasing the AV nodal refractory period

has anti arrhythmic effects involving ion channel blockade in addition to its beta blocking action


how do beta blockers treat hypertension

1. decreasing CO
2. decrease renin secretion