Adrenergic Agents and Blockers Flashcards
The ultimate effect of the sympathetic system is mediated by the release of?
Norepinephrine
Sympathetic activation leads to?
Increased alertness
What is the mechanism of action of an indirect adrenergic agonist?
Inhibit re-uptake of norepinephrine from the synaptic cleft
What receptor is activated in the pre-synaptic membrane will inhibit neurotransmitter release?
Alpha-2
What receptor is activated invovles stimulation of phospholipase c?
Alpha-1
What adrenergic system is predominantly found in the heart?
Beta-1
Alpha-2 receptor is coupled to what protein?
G-protein
Prolonged mechanism of action of ephedrine is due to?
Substitution of the alpha carbon
Post-synaptic activation of alpha-1 receptor will lead to?
Nasal Decongestion
Beta-2 receptor activation will lead to?
Glycogenolysis
A adrenergic agonist which can dilate splanchnic and renal vasculature and can increase contraction and peripheral vascular resistance?
Dopamine
Methlydopa is selective for?
Alpha-2
Beta-2 adrenergic receptor agonists are useful in?
Pre-term labor
Bradycardia observed in norepinephrine can be explained by?
Baroreceptor reflex
An adolescent brought to the emergency room presenting with aggressive behavior, tremor, anxiety, paranoid state, hypertension and tachycardia was diagnosed to have metamphetamine abuse. What is the action ampetamine?
It deplaces norepinephrine from vesicles
What is the side effect of post-synaptic alpha receptor blockade?
Orthostatic hypotension
What is the reason behind the avoidance of beta blockers in diabetes?
Beta blockers may mask symptoms of hypoglycemia
What enzyme metabolizes metoprolol?
Cytochrom P450 2D6 (CYP2D6)
Beta blockers are contraindicated in what condition?
Asthma
What beta-1 selective blocker has a half life of 10 to 15 minutes?
Esmolol
What drug is a non-selective beta blocker?
Propanolol
What drug is both a non-selective beta and alpha blocker?
Carvedilol
What drug is a non-selective beta blocker with partial agonist activity?
Pindolol
What is the mechanism of action of indirect adrenergic agonists?
Blocks MAO
Adrenoreceptor coupled to Gq-protein and especially found in smooth muscles?
Alpha-1
What is structure-activity relationship?
Increase in alkyl substitution in amino group will increase beta receptor activity
Decrease substitution in benzene ring will decrease potency
Substitution in alpha carbon prolongs drug activity
What is the endocrine effect of beta-1 receptor activation?
Stimulation of renin release
What is the effect of low dose dopamine in patients with septic shock?
Increase renal blood flow
Alpha-2 receptor activation will lead to?
Vasoconstirction
Bronchodilation
Decrease in insulin and renin release
Alpha-1 blockers are beneficial in?
Urinary retention
What is an adverse effect of adrenoreceptor blocker?
Severe bradycardia
What is the mechanism of action of reserpine?
Inhibits VMAT
Additional effect of some beta blockers like labetalol and pirdolol which can prevent untoward effects like asthma and bradycardia is due to?
Partial agonist effect
What drug is an alpha 1=alpha 2; beta 1>> beta 2?
Phenylephrine
What drug is an alpha 1=alpha 2; beta 1=beta 2?
Epinephrine
What drug is a beta 1>beta 2>>>>alpha?
Terbutalin
What drug is a beta 2>>beta 1>>>alpha?
Dobutamine
What drug is used in diarrhea among diabetic with autonomic neuropathy?
Clonidine
What drug is used in anaphylactic shock?
Epinephrine
What drug is a long acting selective beta blocker?
Atenolol
What drug is a selective alpha-1 antagonist?
Prazosin
What drug is an alpha receptor irreversible antagonist?
Phenoxybenzamine
What adrenoreceptor inhibits adenyl cyclse causing a decrease in cAMP?
Alpha-2
A patient rushed to the emergency room for anaphylactic shock was given IM epinephrine. Resulting vasoconstriction is mediated by which adrenoreceptor?
Alpha-1
What adrenoreceptor has this order of potency: isoproterenol>epinephrine>>norepinephrine?
Beta-1
A 63 year old male presenting with both hypertension and urinary obstruction secondary to benign prostatic hypertrophy will benefit from what drug?
Prazosin
A patient diagnosed to have pheochromocytoma was started in a non-selective alpha antagonist. An example of which is?
Phentolamine
Phenoxybenzamine
Post-synaptic activation of alpa-1 receptors will lead to what cellular effects?
Increased IP3 and DAG
What drug depends on the normal stores of catecholamines for its sympathomimetic action?
Amphetamine
Which drug will decrease heart rate in a normal heart but has little or no effect in a denervated heart?
Phenylephrine
What are the metabolic effects of beta blockers?
Increased VLDL and decreased HDL with chronic use
Beta adrenoreceptor antagonist are used clinically in?
Portal hypertension
Glaucoma
Chronic heart failure
What adrenoreceptors are found on juxtaglomerular cells?
Beta-1
What are sympathomimetic effects in the CNS?
Elevation of mood
Euphoria
Psychosis
What beta-1 selective blocker with partial agonist activity will minimize or prevent asthma and bradycardia?
Acetabulol
Cartelol
Labetalol
Pindolol