Adrenergics II Flashcards
Reduction is SA node pace and decreasing cardiac contractility is accomplished by modulating which type of receptor?
Muscarinic (M2)
What is the effect of cholinergic stimulation to the SA node? AV node?
SA - Decrease HR
AV - Decrease conduction velocity, increase refractory period
What is the effect of cholinergic stimulation to the Atria? Ventricles?
Atria - Decreased contractile strength
Ventricle - Small decrease in contractile strength
The major effects of the sympathetic NS on the heart are accomplished via what adrenergic receptor?
Beta 1 (mainly)
What is the effect of sympathetic NS stim on the eye? Parasymp?
Symp - mydriasis
Parasymp - Miosis
What is the exception to the rule where the sympathetic NS causes glandular secretion?
Sweat glands - cholinergic post-ganglionic sympathetic neurons
Stimulation of what receptor will Lead to blood vessel constriction in cardiac and skeletal muscle? What about dilation?
Constriction - Alpha 1
Dilation - Beta 2
Stimulation of what receptor will Lead to blood vessel constriction in the skin and GI tract?
Alpha 1
Symp or parasymp; which is responsible for erection? ejaculation?
Erection - parasymp
Ejaculation - symp
Increased glycogenolysis in liver and skeletal muscle, and increased insulin secretion occurs because of stimulation of what type of adrenergic receptor?
Beta 2
Sympathetic NS mediated increased lypolysis is accomplished via stimulation of what receptors (2)?
Beta 1 and beta 3
What are the 2 adrenergic type receptors found on presynaptic sites?
Alpha 2 and DA 2
Drugs stimulating the adrenergic system will likely treat _, while drugs inhibiting it will likely treat _ [hypo/hypertension]
Stimulate - hypotension
Inhibit - hypertension
Clonidine, guanabenz and alpha-methyldopa are all examples of _. They are used to promote _
Alpha 2 receptor agonists
Hypotension
What are six side effects associated with alpha 2 receptor agonists?
sedation, xerostomia,
anorexia, fluid retention,
vivid dreams & CNS
stimulation
What is the target of bromocriptine? What is the clinical use?
DA 2 receptor agonist
Treatment of Parkinson’s with CNS effects
What are 2 expected side effects of D2 receptor agonists (bromocriptine)? What is the location of the receptors that mediate its side effects?
Postural hypotension
Cardiac arrhythmia
Peripheral NS - desired targets in CNS
What is the mechanism of action of reserpine? How does it get into the presynaptic terminal?
Reduces biogenic amines stored in vesicles / released
Enters in presynaptic terminal via amine 1 transporter AKA Norepinephrine Transporter
What are the biogenic amines that can be affected by reserpine?
Epi, DA, NE, serotonin
What are 3 expected CNS side effects of reserpine?
Sedation
Depression
Parkinsonian symptoms
What is the side effect of reserpine on GI function?
Increased motility, ulcers
What is the mechanism by which guanethidine functions? What are the indications?
Stabilizes membranes, depletes vesicles containing NE
Severely elevated arterial pressures
What is the expected effect of cocaine and tricyclic antidepressants on guanethidine function? How does guanethidine enter the presynaptic terminal?
Cocaine and TCAs block transport of NE back into the synapse, therefore antagonize guanethidine function
Enters synapse via amine 1 transporter (AKA NET)
What is the effect of chronic guanethidine use? How does it affect epinephine and DA? What are the CNS side effects?
Chronic use deplete NE
No effects on epi and DA
No CNS effects, doesn’t cross BBB
What is the mechanism of action of alpha-methyldopa? What is it used to treat?
Alphamethyldopa mimics DOPA in synthetic pathway, causing synthesis of false NE (reduced efficacy)
Used to treat hypertension
How does alphamethyldopa cause its hypotensive effects?
Stimulation of brainstem vasomotor center
What are 6 potential side effects associated with alpha methyl dopa?
Sedation, dizziness, sleep disturbance, impotence, dry mouth and nasal congestion
Why does chronic therapy with alpha methyl DOPA require close monitoring?
Chronic therapy can cause severe problems like hemolytic anemia, leukopenia, lupus and hepatitis
What are the 4 examples of alpha 1 selective antagonists provided? Which is least alpha 1 selective***?
Prazosin
Terazosin
Doxazosin
Phenoxybenzamine ***
What is the example provided that antagonizes alpha 1 and alpha 2 equally?
Phentolamine
Phenoxybenzamine preferential targets which alpha receptor?
Alpha 1 over alpha 2
A mixed antagonist that will target both beta and alpha receptors is _. Which of the two will it bind to better?
Labetalol
Beta receptors
What are the three examples of beta specific antagonists provided? Which beta receptor do they preferentially bind?
Atenolol
Betaxolol
Metoprolol
Beta 1 over beta 2
What are the 3 examples of antagonists drugs that bind equally to beta receptors?
Propranolol
Pindolol
Timolol
What is the mechanism of action of phenoxybenzamine (2)? How long does it act?
Non competitively and covalently binds alpha 1 receptor, blocks NE binding
Covalently binds amine 1 transporter, blocks NE uptake
24 hrs
Phenoxybenzamine can cause hypotension and tachycardia. Why?
Takes out majority of alpha 1 receptors, leading to reflex activation of the adrenergic branch of NS
What are the clinical uses of phenoxybenzamine?
Pheochromocytoma (inoperable / metastatic tumor)
Severe hypertension
What is the example of the non-competitive alpha 1 blocker provided?
Phenoxybenzamine
What is the mechanism of action of prazosin?
Competitive alpha 1 blocker
Phenoxybenzamine and prazosin both block alpha 1 receptors. How do they compare?
Phenoxybenzamine is non-competitive
Prazosin is competitive
What is the use of prazosin? How long does it last?
Used for hypertension
Lasts for 12 hrs
What are the receptor targets of phentolamine? WHat are its effects
Competitive alpha 1 and alpha 2 receptor antagonist
Vasodilation - alpha 1
Increased NE release - alpha 2
Phentolamine is considered a dirty drug. What other receptor subtypes will it bind (2)?
Histamine and Muscarinic receptors
Among Prazosin, phentolamine and phenoxybenzamine, which 2 are likely to cause tachycardia? Increased cardiac output? Postural hypotension?
Respectively…
Phentolamine and phenoxybenzamine
Phentolamine
Phenoxybenzamine
What is the clinical use of phentolamine?
Pheochromocytoma induced hypertension
The major use of beta blockers is for the treatment of _. They are used in conjuntion with what other types of drugs?
Hypertension
Diuretics
4 examples provided of beta 1/2 blockers are _. Where do these drugs work (pre/post synaptic)
Propranolol Pindolol Timolol Nadolol Postsynaptic
Why are combined beta 1/2 blockers notable for patients with asthma?
Might block bronchiole dialation
Propranolol and Timolol are significant for MI because _
Can potentially prevent myocardial infarction reoccurence
What drug is widely used to reduce intraoccular pressure (beta blocker)?
Timolol
Why is nadolol different from the other combined 3 beta blocker presented?
Works for 14-24 hrs, vs 3-5 hrs for others
In addition to antihypertensive, what drug is also indicated for migraine, antiarrhythmia and angina pectoris?
Propranolol
What are the 4 beta 1 specific antagonists presented? What are their significance
Betaxolol Atenolol Metoprolol Esmolol Cardiac specific
Beta blockers may not always be completely specific. What group of patients have to be monitored carefully when on these drugs?
Asthma and COPD patients
Of the beta 1 specific drugs, which can prevent reoccurence of MI?
Metoprolol
Which 2 beta blockers are most likely to cause ataxia and dizziness?
Propranolol
Metoprolol
Which to beta blockers are least likely to cause CNS side effects?
Nadolol
Atenolol
What are the dangers of using beta blockers on patients with cardiac problem?
Can cause heart failure (beta 1 block reduces HR, contraction force, CO)
What 4 adrenergic antagonists can be used to treat urinary obstruction secondary to prostatic hyperplasia? What receptor do they target?
Prazosin Doxazosin Terazosin Tamsulosin Alpha 1 selective
What 3 beta blockers might prolong survival following MI?
Timolol
Propranolol
Metoprolol
What are 2 drugs used to treat pheochromocytoma preoperatively?
Phenoxybenzamine
Phentolamine
