Adrenergic Agonists and Antagonists

Question 1

What are the indirect acting NE releasers?

Answer 1

Tyramine
Amphetamine
Ephedrine

Question 2

Where is tyramine normally found?

Answer 2

Diet, aged/fermented foods like cheese and wine

Question 3

Why does dietary tyramine not normally cause NE release?

Answer 3

Normally oxidized by MAO in gut and liver before reaching the circulation
MAO-I inhibitors will allow NE release

Question 4

What are amphetamines used to treat?

Answer 4

Narcolepsy and ADD

Question 5

What is the mechanism of action of ephedrine?

Answer 5

NE releaser and weak Beta2 agonist

Question 6

What are the uses of ephedrine?

Answer 6

Decongestant
Vasopressor (BP increased)
Stress urinary incontinence (contracts bladder sphincter)

Question 7

What is the difference between ephedrine and pseudoephedrine?

Answer 7

Less psychostimulant

Less CV effects with equivalent decongestant potency

Question 8

What is the mechanism of NE release caused by the indirect acting NE releasers?

Answer 8

Nonvesicular release
NE-releaser displaces NE from vesicle to cytoplasm
NE released by reversal of NET

Question 9

What is the mechanism by which cocaine increases NE?

Answer 9

Blocks neuronal NE uptake by NET

Question 10

What is the direct-acting Alpha1 agonist?

Answer 10

Phenylephrine

Question 11

What are the uses of phenylephrine?

Answer 11

Decongestant, vasoconstriction, mydriasis

Question 12

What are the direct-acting Alpha2 agonists?

Answer 12

Clonidine

Brimonidine

Question 13

What is clonidine used for?

Answer 13

Reduces sympathetic activity by inhibiting NE release (alpha2 receptors are autoreceptors)
Used for hypertension

Question 14

What is Brimonidine used for?

Answer 14

Analog of clonidine, used to treat IOP

Question 15

What are the direct-acting Beta2 agonists?

Answer 15

Albuterol
Salmeterol
Formoterol
Ritodrine

Question 16

Which beta2 agonists are used for asthma?

Answer 16

Albuterol
Salmeterol
Formoterol

Question 17

What is Ritodrine used for?

Answer 17

Delay preterm labor

Question 18

What is the direct-acting Beta3 agonist?

Answer 18

Mirabegron

Question 19

What is Mirabegron used for?

Answer 19

Treat overactive urinary bladder syndrome by relaxing the detrussor

Question 20

What are Alpha 1 & 2 antagonists?

Answer 20

Phenoxybenzamine

Phentolamine

Question 21

What are the Alpha 1 & 2 antagonists used for?

Answer 21

Management of pheochromocytoma (catecholamine-secreting tumors)

Question 22

What is important to remember about the treatment of pheochromocytomas?

Answer 22

Alpha block must be in place before use of a beta block

If beta receptor was blocked first, would cause huge vasconstriction and increased blood pressure

Question 23

What are the Alpha 1 specific antagonists and which is Alpha-1A selective?

Answer 23

Prazosin
Terazosin
Tamsulosin - Alpha-1A selective

Question 24

What are prazosin and terazosin used for?

Answer 24

Primary hypertension - causes vasodilation
Vasodilation in peripheral vascular disease (Raynaud’s)
Relaxation of urinary tract smooth muscle - helpful in benign prostatic hypertrophy and voiding kidney stones

Question 25

What is tamsulosin used for?

Answer 25

Selective relaxant of urinary tract smooth muscle with less vasodilator

Question 26

What is the Alpha 2 selective antagonist?

Answer 26

Yohimbine

Question 27

What is yohimbine used for?

Answer 27

Increased NE release and increased vasoconstriction

Question 28

What are adverse effects of alpha 1 block?

Answer 28

Postural hypotension
Nasal congestion
Dry mouth
Intraoperative floppy iris syndrome (IFIS)
Retrograde ejaculation (relaxed internal sphincter allows it back up)
Delayed ejaculation (reduced propulsion of seminal fluid along vas deferens
Priapism

Question 29

Why does alpha 1 block cause priapism?

Answer 29

Sympathetic adrenergic input and contraction of vascular and trabecular smooth muscle maintains flaccidity
Blockage of sympathetic tone relaxes blood vessels, facilitating inflow of blood and compressing veins that are draining blood, resulting in engorgement and rigidity

Question 30

What are the non selective Beta blockers?

Answer 30

Propanolol
Timolol
Pindolol

Question 31

What are cardiovascular indications for the use of Beta blockers?

Answer 31

Typical effort angina
Postinfarction
Arrhythmias
Systolic heart failure
Primary hypertension

Question 32

What are other indications (not CV) for the use of beta blockers?

Answer 32

Hyperthyroidism
Migraine
Glaucoma
Tremors

Question 33

What are the Beta-1 selective blockers?

Answer 33

Atenolol

Metoprolol

Question 34

What are the nonselective beta blockers with additional vasodilator actions?

Answer 34

Carvedilol

Labetalol

Question 35

Through what receptor does Labetalol exert its additional vasodilator effects?

Answer 35

Alpha 1

is an alpha1 & beta blocker

Question 36

Which nonselective beta blocker is also a partial beta agonist and why is this useful?

Answer 36

Pindolol

Partial agonism may be advantageous in patients with bradycardia or partial conduction block

Question 37

Which nonselective beta blocker has high lipid solubility?

Answer 37

Propranolol

Allows it to cross BBB, placenta

Question 38

What are cardiovascular adverse effects of beta blockers?

Answer 38

Decreased exercise capacity
Bradycardia
AV conduction block
Heart failure
Peripheral vasoconstriction (cold extremities)
Withdrawal beta-supersensitivity

Question 39

What are non-CV adverse effects of beta blockers?

Answer 39

Bronchoconstriction (contraindicated in asthma/COPD)
Mast cell destabilization (dumping of inflammatory mediators, complicates treatment of anaphylaxis with epi)
Exercise induced hyperkalemia