Alpha and Beta Receptor Antagonist Flashcards
(51 cards)
blocking alpha 2 receptor will have a similar effect as ___________ the beta receptor.
stimulating
List the effect of beta 2 agonist on : Blood vessels Bronchioles Uterus Kidneys Liver Pancreas
Blood vessels-dilation Bronchioles-dilation Uterus-Relaxation Kidneys-Renin secretion Liver-Glycogenolysis+Gluconeogenesis Pancreas-insulin secretion
What are the effects of alpha 1 activation on :
Bklood vessles
Pancreas
Intestine and bladder
Blood vessels-constrict
Pancreas-inhibition of insulin secretion
Intestine and bladder: Relaxion + constriction of sphincters
What are the effects of alpha 2 activation on:
postganglionic/presynaptic nerve ending
CNS (presynaptic)
Platelets
Postganglionic: Inhibition of norepi release
CNS: Increase of K+ conductance
Platelets: aggregation
What are clinical uses of alpha antagonism?
Tx of: pheochromocytoma CHF BPH Raynauds
What are the effects fo alpha 2 blockade?
Increased sympathetic outflow and increased release of epi from nerve endings
What are the effects of alpha adrenergic receptor antagonists. What are side effects?
Binds selectively to alpha receptors to block effects of catecholamines at receptor sites
Causes orthostatic hypotension and syncope
Reflex tachycardia
Impotence
What are uses for phentoalamine.
Phentoalamine is a competive nonselcetive alpha antagoinst used to treat acute hypertensive emergencies s.a. pheochromocytoma or autonomic nervous system hyperreflexia.
Alpha 1 blockade causes decrease in Systemic BP, reflex tachycardia
Apha 2 blockade causes a release of norepi increasing HR and CO. It also gives a parasympathetic response s.a. abdominal pain and diarrhea
What kind of drug is prazosin? How does it work? What are its uses?
Prazosin is an alpha 1 selective competive alpha antagonist
Its effects: less likely reflex tachycardia
Dilates both art and venous
Primarily antihypertensive
Used for preop bp in pheochromocytoma and in reynauds and BPH
How do taxazosin and tamulosin work?
Act preferentially on alpha-1 receptors of vesical trigone muscle, urethra, and prostate
Relax prostatic smooth muscle to tx BPH
Where does yohimbine work?
What is its clinical use?
Selective antagonist at presynaptic alpha 2
Increases release of norepi
Used as a tx for idiopathic orthostatic hypotension
Tx for impotence
Too much causes tachycardia and hypertension
HOw does phenoxybenzamine interact with the receptor?
What is duration of action?
Non competitive (irreversible) nonselective alpha blocker Alpha 1 > alpha 2 Lasts for 14-48 hours or longer
What are the uses for phenoxybenzamine?
Used as preop tx for pts with raynaud’s or pheochromocytoma
Prevents inhibitory action of epi on secretion of insulin
Causes orthostatic hypotension
What are the cardiovascular uses of beta blockers?
Treatment of essential hypertension Management of Angina Pectoris Treatment of Acute Coronary Syndrome Perioperative Beta blockade Treatment of Intraoperative myocardial ischemia Supression of Cardiac Dysrythmias Mangagement of Congestive Heart Failure Preop prep of hyperthyroid
Beta blocker therapy should be continued thru the periop period. t/f
T
What are two strategies to prevent/treat cardiac ischemia?
Minimize cardiac O2 demand
Maximize O2 supply
What are uses of beta blockers that are not cardiac related?
prevention of primary and secondary digestive bleeding in portal hypertension by rupture of esophageal varices
treatment of migraine, tremor, transitory somatic symptoms of anxiety, alcohol addiction in which there appears a beta overstimulation
treatment of glaucoma by ophthalmic solutions
Beta blockers are competitive inhibitors. What determines whether partial or full antagonism?
What drug would be used to overcome beta blockers?
Competitive inhibition over come by atropine
Partial or full antagonist based on intrinsic sympathomimetic activity
Beta blocker receptor selectivity is _______ dependent
Dose
What are the CV side effects of beta blockers?
(-) iontropic and chronotropic
AV node conduction decrease
Accentuates AV block–may increase to a 3rd degree block
(AV blocks are a contraindication to prescription)
Beta blockers may increase concentrations of local anesthetics and fentany T/F?
T
B blockers bind to albumen and kicks the other stuff off
How do beta blockers affect MAC?
decrease
Beta blockers may ________ triglycerides and ________ glucose.
increase triglycerides and cause hypoglycemia.
A rebound in symptoms may occur at abrupt discontinuation
Beta blockers should be continued during lactation. T/F
False, they are contraindicated in lactation
