Adrenergic Antagonists

Question 1

Name the 4 α-antagonists.

Answer 1

Phentolamine, phenoxybenzamine, prazosin, terazosin

Question 2

Name the 2 non-selective α-antagonists. Which one is a non-competitive inhibitor?

Answer 2

Phentolamine and phenoxybenzamine; phenoxybenzamine is non-competitive and forms covalent bonds with the receptors

Question 3

Name the 2 α1-selective antagonists.

Answer 3

Prazosin and terazosin

Question 4

What is a common side effect of all the α-antagonists? What is a common side effect of only the non-selective α-antagonists?

Answer 4

Postural hypotension; inhibition of ejaculation

Question 5

What 3 conditions are phentolamine and phenoxybenzamine used to treat because they inhibit both α1 and α2 receptors?

Answer 5

Pheochromocytoma, Raynaud’s, and frostbite

Question 6

What 2 conditions are prazosine and terazosin used to treat?

Answer 6

Primary hypertension and BPH (benign prostatic hypertrophy)

Question 7

Explain the selectivity of the 1st, 2nd, 3rd “A” and 3rd “B” generation β-antagonists.

Answer 7

1st and 3rd “A”: non-selective (affect β1 and β2)

2nd and 3rd “B”: β1-selective

Question 8

Name all 8 of the β-selective antagonists.

Answer 8

Propranolol, timolol, metoprolol, atenolol, bisoprolol, carvedilol, labetalol, betaxolol

Question 9

Name the 2 non-selective 1st generation β-antagonists. Which one is the standard to which all new β-antagonists are compared?

Answer 9

Propranolol and timolol; propranolol is the old standard

Question 10

Name the 3 β1-selective, 2nd generation β-antagonists.

Answer 10

Metoprolol, atenolol, bisoprolol

Question 11

Name the 3 3rd generation β-antagonists. Which are “A” and which is “B”?

Answer 11

Carvedilol and labetalol: “A”

Betaxolol: “B”

Question 12

What 3 conditions is propranolol used to treat? What other generation of β-antagonists is used to treat all of these conditions?

Answer 12

Angina, hypertension, arrhythmias; the 2nd generation β-antagonists (β1-selective: metoprolol, atenolol, bisoprolol)

Question 13

Name the only β-antagonist not used to treat hypertension. What is it used for instead?

Answer 13

Timolol; glaucoma

Question 14

Which β-antagonists can be used to treat congestive heart failure? Name the 2 generations and the 6 specific drugs.

Answer 14

2nd and 3rd gen β-antagonists: metoprolol, atenolol, bisoprolol, carvedilol, labetalol, betaxolol

Question 15

List all 4 conditions that the 2nd generation β-antagonists are used to treat.

Answer 15

Hypertension, angina, arrhythmia, congestive heart failure

Question 16

What is the major side effect of using any β-antagonist? Which receptor mediates this effect?

Answer 16

Bradycardia, due to β1 antagonism (all β-blockers affect β1)

Question 17

Besides bradycardia, list 3 side effects of β-antagonists, and state which drugs are associated with each effect.

Answer 17

Bronchoconstriction: 1st gen
Sexual dysfunction: 1st and 2nd gen
Fatigue: 3rd gen “A”

Question 18

The 3rd generation “A” β-antagonists have an “additional action.” What is this action and what receptor mediates it?

Answer 18

Vasodilation, due to α1-receptor antagonism

Question 19

Name the 6 miscellaneous adrenergic affectors: 1 indirect acting agonist, 2 street drugs, and 3 nerve ending blockers.

Answer 19

Tyramine, amphetamine, cocaine, guanethidine, reserpine, and α-me-tyrosine

Question 20

Which adrenergic drug should not really be in this deck because it is an indirect agonist and not an antagonist? Describe what kind of protein it binds to and the effect.

Answer 20

Tyramine; binds an exchange transporter and goes into the cell while norepi comes out, increasing cytoplasmic release of norepi

Question 21

Describe how amphetamine acts in the synaptic cleft and what 2 diseases it is used to treat (boredom is not a disease).

Answer 21

Increases norepinephrine release; treat ADHD and narcolepsy

Question 22

Describe how cocaine acts in the synaptic cleft and give 2 medical uses for it.

Answer 22

Decreases norepinephrine reuptake; used for vasoconstriction and as a local anesthetic

Question 23

Give 4 side effects of using amphetamine or cocaine.

Answer 23

Hypertension, insomnia, anxiety, and arrhythmias. (the table doesn’t technically list hypertension for cocaine but close enough)

Question 24

Name the 3 adrenergic nerve ending blockers. Which is the only one used clinically in the U.S.? What is it used for?

Answer 24

Guanethidine, reserpine, and α-me-tyrosine; only α-me-tyrosine is used in the U.S. for pheochromocytoma

Question 25

Which nerve ending blocker is interesting because it is a “false neurotransmitter” that replaces the norepi in presynaptic vesicles?

Answer 25

Guanethidine

Question 26

Which nerve ending blocker has the interesting mechanism of inhibiting the norepi uptake transporter, causing the release of empty vesicles into the synaptic cleft?

Answer 26

Reserpine

Question 27

Reserpine is not used in the U.S., but is popular in other countries as a cheap treatment for what disease? What are 2 significant side effects of usage?

Answer 27

Hypertension; can cause depression and suicide

Question 28

What enzyme does α-me-tyrosine inhibit, and how does this affect norepi?

Answer 28

Inhibits tyrosine hydroxylase, causing decreased synthesis of norepi

Question 29

Distinguish between α-me-tyrosine and α-me-dopa in terms of receptor targets and therapeutic effect.

Answer 29

α-me-dopa is an α2 agonist in the CNS, used to treat hypertension
α-me-tyrosine is a miscellaneous norepi inhibitor that inhibits tyrosine hydroxylase and is used to treat pheochromocytoma