Adrenergic Antagonist: Adrenergic receptor blockers Flashcards
agents that produce their major actions inhibiting α and β receptors.
Adrenergic antagonists
Adrenergic antagonists block the effects of both exogenously administered as well as endogenously released__________
catecholamines
Adrenergic antagonists bind receptors and compete with ________
May affect release of____ from sympathetic fibers
agonists
NE
T/F
Adrenergic antagonists often abolish the responses mediated through other types of receptors
F; they generally don’t do this
Phenoxybenzamine and phentolamine are:
α adrenergic antagonists (generally 1 and 2)
phenoxybenzamine is an________ antagonist
irreversible
Phenoxybenzamine works via what type of bonding?
covalent
phenoxybenzamine is orally active; long duration of action; blockade persists for days; thus we need to do what to overcome it’s action
need to resynthesize receptors
This drg produces vasodilation proportional to the degree of sympathetic tone
phenoxybenzamine
Phentolamine is a:
competitive reversible antagonist
This adrenergic antgonist is orally active; shorter duration of action, and it’s block can be overcome by increasing levels of agonists
phentolamine
Why can phentolamine ve overcome by increaseing levels of agonists
because it’s competitive reversible
Phentolamine is uses to tx: _______– in combination with other agents
hypertension
pheochromocytoma is treated with:
(phenoxybenzamine, phentolamine)
why would you use phetolamine or phenoxybenamine if you had someone anesthitizes
to reverse or shorten the duration of soft-tissue anesthesia produced by
combined local anesthetic and sympathomimetic
Side effects of phenoxybenzamine and phentolamine (severely limit usefulness) and include:
tachycardia and salt/water retention (edema) - orthostatic hypotension
Selective orally active competitive blocker of α1 receptors
Prazosin
What does Prazosin work?
Selective orally active competitive blocker of α1 receptors
How does Prazosin improve your lipid profile?
Produces favorable lipid profile - ↓ LDL, ↑ HDL
Produces favorable lipid profile - ↓ LDL, ↑ HDL
Prazosin
What effect does Prazosin have on arterioles and veins?
Decreases vascular tone in resistance (arterioles) and capacitance (veins) beds
Because Prazosin has little blockade of __________ reflex tachycardia is less
problematic - minimal increase in cardiac output
pre-synaptic α2 receptors
Major clinical uses of Prazosin
- preload and afterload________ agent
reducing
– relaxes α1 mediated contraction of
prostate and bladder neck that contributes to resistance to urine flow
Prazosin
Treatment option for Benign Prostatic Hyperplasia (BPH)
Prazosin
How does Prazosin help with hypertension/hypotension?
Hypertension
Would you use Prazosin for long term tx option of congestive heart failure?
Nope: Short-term treatment of congestive heart failure
Major side effects of Prazosin known as ‘first dose effect’ is what?
hypotension and syncope 30-90 min after the first dose – administer the first dose at bedtime
Prazosin can occastionally causes persistant:
orthostatic hypotension (occasionally)
Prazosin causes edema: T/F
True
Tamsulosin is an orally active:
- Favors blockade of α1A receptors in prostate (versus subtypes in blood vessels) - Effective for treatment of BPH with little effect on blood pressure (less propensity
for orthostatic hypotension) - not approved for treatment of hypertension - Silodosin (Rapaflo®) – also exhibits selectivity for α1A over α1B receptors and used
for BPH
α1 receptor antagonist with some selectivity for α1A versus α1B subtypes
Tamsulosin has some selectivity for _____ versus ____ subtypes
α1A
α1B
Tamsulosin gavors blockade of α1A receptors in_______ (versus subtypes in blood vessels)
prostate
Effective for treatment of BPH with little effect on blood pressure (less propensity
for orthostatic hypotension)
Tamsulosin
T/F
Tamulosin is approved for treatment of hypertension
False
