Adrenergic

Question 1

NE activates which receptors?

Answer 1

alpha-1, beta-1, and alpha-2

Question 2

Epi activates which receptors?

Answer 2

alpha-1, beta-1, and beta-2

Question 3

Reserpine

Answer 3

Indirect inhibitors of SNS NT
Depletes monoamine NT from PNS/CNS terminals (Epi, NE, DA, 5-HT) by inhibiting uptake of synaptic vesicles. Can cause severe depression by crossing BBB. Rarely used due to side effects.

Question 4

Guanethidine

Answer 4

Indirect inhibitors of SNS NT
Displaces catecholamine in synaptic vesicles, eventually leading to depletion and replacement of NT. No CNS activity/does not cross BBB. Minor: blockade of post-synaptic receptors and reuptake.

Question 5

Bretylium

Answer 5

Indirect inhibitors of SNS NT
Blocks depolarization-induced NE release. No CNS activity/does not cross BBB. Pronounced membrane stabilization–local anesthetic effect. Used to treat v-fib and dysrhythmias.

Question 6

Ephedrine, Pseudoephedrine

Answer 6

Indirect sympathomimetic
Action in part due to release of NE, causing mild cardiac stimulation, decongestion. Pseudoephedrine OTC or Rx depending on state–easily made into methamphetamine.

Question 7

Amphetamine, Methylphenidate

Answer 7

Indirect sympathomimetic
Most of action due to release of NE. Used to treat ADHD, but also widely used illicitly. High doses lead to pronounced cardiac stimulation.

Question 8

–nidine drug ending indicates:

Answer 8

alpha-2 agonist, direct sympathomimetic

Question 9

–terol drug ending indicates:

Answer 9

beta-2 agonist, direct sympathomimetic

Question 10

–osin drug ending indicates:

Answer 10

alpha-1 antagonist, direct sympathomimetic

Question 11

–olol drug ending indicates:

Answer 11

beta antagonist, direct sympathomimetic

Question 12

–stigmine drug ending indicates:

Answer 12

AChE inhibitor, direct sympathomimetic

Question 13

Isoproteronol

Answer 13

Beta-agonist (nonselective). Treats bradycardia, used in ICU and OR. Also produces profound vasodilation (reflex tachycardia).

Question 14

Albuterol, terbutaline, levalbuterol, salmeterol

Answer 14

Beta-2-agonist. Preferential activity for smooth muscle.

Question 15

Dobutamine

Answer 15

Beta-1-agonist. Increases HR and contractility with less vasoconstriction. Used primarily for cardiogenic shock IV in ICU.

Question 16

Therapeutic use: Asthma, COPD

Answer 16

Beta-2-agonists: bronchodilators (SM relaxation –> opening of the airways). Terbutaline, albuterol, salmeterol, levalbuterol)

Question 17

Therapeutic use beta-agonist: cardiac

Answer 17

Isoproterenol: cardiac stimulant used to overcome bradycardia and some specific arrhythmias.
Dobutamine: cardiac stimulant used in cases of acute CHF and MI. Some alpha agonist activity.

Question 18

Adverse effects of beta-agonists

Answer 18

Severe tachycardia (overstimulation SA node)
Cardiac arrhythmias (decreased electrical stability)
Angina pectoris (cardiac stimulation --> increased O2 demand. In extreme cases, can lead to necrosis of cardiac tissue and MI)
Skeletal muscle weakness (promotes K uptake --> hyperpolarization --> muscle weakness)

Question 19

Propranolol

Answer 19

Beta-blocker (nonselective). Poor bioavailability. Decreased liver function can lead to high blood levels and increased toxicity.

Question 20

Atenolol, Bisoprolol, Metoprolol

Answer 20

Beta-1-antagonists

Question 21

Esmolol

Answer 21

Beta-1-antagonist. Very short half-life in plasma. Used IV in ICU settings (quickly is out of system if bad reaction).

Question 22

Carvedilol, Labetalol

Answer 22

Mixed antagonists against beta-1, beta-2, and alpha-1. Produces a smaller increase in peripheral vascular resistance by relaxing vascular smooth muscle. This vasodilating effect is desirable in HTN and CHF treatment.

Question 23

Adverse effects beta-antagonists

Answer 23

Generally fall into one of two categories:

• bronchoconstriction due to blockade of beta-2 receptors of bronchial SM
• severe bradycardia heart block due to over-blockade of cardiac beta-1 receptors

Question 24

–olol drug ending indicates:

Answer 24

pure beta-blockade

Question 25

--alol or --ilol drug ending indicates:

Answer 25

mixed blockade function. Beta-blockage and something else

Question 26

Peripheral alpha-1- and -2-agonists:

Answer 26

Increase vasoconstriction. Used topically, in injections, and IV

Question 27

Central alpha-2-agonists:

Answer 27

Decrease sympathetic tone, slow HR, decrease CO, decrease vasoconstriction

Question 28

Methoxamine, phenylephrine

Answer 28

Pure alpha agonist (1>2). Methoxamine is used for the treatment of acute hypotensive crisis (produces reflex baroreceptor bradycardia (diving reflex, decreased HR). The heart only has beta-1 receptors, so the bradycardia is an indirect effect of this drug.

Question 29

Norepinephrine

Answer 29

Stimulates alpha and beta-1 receptors. Net effect of vasoconstriction and increased HR and contractility. (Weak beta-2 stimulant)

Question 30

Phentermine

Answer 30

Alpha>beta agonist. Used in weight loss alone or in combination with topiramate

Question 31

Clonidine

Answer 31

Selective central alpha-2-agonist. HTN med.

Question 32

Methyldopa

Answer 32

Prodrug, acts centrally. Net effect of decreased sympathetic outflow. Converted to active methyl-NE in the CNS. Adverse effects when active drug enters systemic circulation, including HTN, coronary ischemia, cerebral ischemia, and local necrosis at injection site.

Question 33

Therapeutic uses of alpha-agonists:

Answer 33

``` Nasal congestion (Constriction of blood vessels in nasal mucosa counteracts swelling and congestion of nasal passages) Local anesthetics (Vasoconstriction of vessels at site of injection, prolongation of anesthetic affect) Ocular preparations (Constriction of vessels on surface of eye --> decreased redness) Anaphylactic shock (Epi reverses hypotension [alpha-1] and bronchoconstriction [beta-2], and inhibits histamine release by mast cells [beta-2]) ```

Question 34

Adverse effects of alpha-agonists

Answer 34

``` Hypertension (vasoconstriction of arterial SM [alpha-1]) Myocardial necrosis/infarction (extreme alpha-mediated vasoconstriction of coronary arteries) Cerebrovascular accident (alpha-mediated constriction of cerebral vessels) ```

Question 35

Epinephrine

Answer 35

Potent cardiac stimulant (beta-1) and vasoconstrictor (alpha-1). Effect is dose dependent: Beta receptors are more sensitive than alpha, so at low doses they are preferentially stimulated. At high doses, however, the alpha effect can override the beta. Therefore, a biphasic response can result following epi injection (high dose effect at first, low dose effect as epi is metabolized).

Question 36

Effects on the heart by epinephrine

Answer 36

Stimulates beta-1 receptors = cardiac stimulant. Increased HR, conduction velocity, ventricular contraction.

Question 37

Effects on vascular SM by epinephrine

Answer 37

Effects are dependent on several factors, including the dose, route of admin, type of receptors predominating in a given vascular bed. Therefore, effect of epi in a given situation is very difficult to predict.

Question 38

Phentolamine, Pheonxybenzamine

Answer 38

Alpha-1 and -2 non-selective antagonists. Used for special situations: pheochromocytoma, Reynaud's syndrome.

Question 39

Doxazosin, Prazosin, Tamsulosin, Terazosin

Answer 39

Alpha-1 antagonists. Tamsulosin is used more to treat prostatic hypertrophy.