Pharm - Autonomic Drugs (Sympathomimetic Specifics)

Question 1

Compare/Contrast the use and effects of Norepinephrine and Isoproterenol.

Answer 1

NOREPINEPHRINE causes an increase in systolic and diastolic pressures as a result of alpha 1 -mediated vasoconstriction => increased mean arterial pressure => bradycardia. However, ISOPROTERENOL (no longer commonly used) has little alpha effect but causes Beta2-mediated vasodilation, resulting in decreased mean arterial pressure and increased heart rate through Beta 1 and reflex activity

Question 2

Draw graphs showing diastolic, mean, and systolic blood pressures for Norepinephrine versus Isoproterenol.

Answer 2

See p. 249 in First Aid 2014 for visuals

Question 3

Draw graphs showing heart rate for Norepinephrine versus Isoproterenol.

Answer 3

See p. 249 in First Aid 2014 for visuals

Question 4

What is another name for Sympatholytics? Give 2 examples of such drugs.

Answer 4

Sympatholytics (Alpha2-agonists); (1) Clonidine (2) Alpha-Methyldopa

Question 5

What are 4 clinical applications for Clonidine? What is an important consideration for one of these applications?

Answer 5

(1) Hypertensive urgency (limited situations); does not decrease renal blood flow, (2) ADHD, (3) severe pain, and a (4) variety of off-label indications (e.g., ethanol and opioid withdrawal)

Question 6

What are 5 toxicities associated with the use of Clonidine?

Answer 6

(1) CNS depression, (2) Bradycardia, (3) Hypotension, (4) Respiratory depression, and (5) Small pupil size

Question 7

What is a major clinical application of alpha-methyldopa? What is an important consideration for this application?

Answer 7

Hypertension in pregnancy; Safe in pregnancy

Question 8

What are 2 toxicities associated with the use of alpha-methyldopa?

Answer 8

(1) Direct Coombs positive hemolytic anemia (2) SLE-like syndrome

Question 9

What are 2 examples of nonselective alpha-blockers? Which is reversible versus irreversible?

Answer 9

(1) Phenoxybenzamine (irreversible) (2) Phentolamine (reversible)

Question 10

What is the clinical application for Phenoxybenzamine?

Answer 10

Pheochromocytoma (used preoperatively) to prevent catecholamine (hypertensive) crisis

Question 11

What are 2 toxicities associated with Phenoxybenzamine?

Answer 11

(1) Orthostatic hypertension (2) Reflex tachycardia

Question 12

What is the clinical application for Phentolamine?

Answer 12

Give to patients on MAO inhibitors who eat tyramine-containing foods

Question 13

What are 4 examples of alpha 1 selective alpha blockers? What do their names all have in common?

Answer 13

(1) Prazosin (2) Terazosin (3) Doxazosin (4) Tamsulosin; (-osin ending)

Question 14

What are 3 clinical applications for Prazosin, terazosin, doxazosin, and tamsulosin (i.e., alpha 1 selective alpha blockers)? Where applicable, specify which drugs are used in each context.

Answer 14

(1) Urinary symptoms of BPH; (2) PTSD (Prazosin); (3) Hypertension (except Tamsulosin)

Question 15

What are 3 toxicities associated with Prazosin, terazosin, doxazosin, and tamsulosin (i.e., alpha 1 selective alpha blockers)?

Answer 15

(1) 1st dose orthostatic hypotension (2) Dizziness (3) Headache

Question 16

What is an example of an alpha 2 selective alpha-blocker?

Answer 16

Mirtazapine

Question 17

What is the clinical application for Mirtazapine?

Answer 17

Depression

Question 18

What are 3 toxicities associated with Mirtazapine?

Answer 18

(1) Sedation (2) Increased serum cholesterol (3) Increased appetite

Question 19

Explain the effects of an alpha-blocker (e.g., phentolamine) on blood pressure responses to epinephrine versus phenlephrine.

Answer 19

The epinephrine response exhibits reversal of the mean blood pressure change, from a net increase (the alpha response) to a net decrease (the Beta 2 response). The response to phenylephrine is suppressed but not reversed because phenylephrine is “pure” alpha-agonist without beta action.

Question 20

Draw the effects of epinephrine versus phenlephrine before and after alpha blockade.

Answer 20

See p. 250 in First Aid 2014 for visual

Question 21

Name 10 beta-blockers.

Answer 21

(1) Metoprolol (2) Acebutolol (3) Betaxolol (4) Carvedilol (5) Esmolol (6) Atenolol (7) Nadolol (8) Timolol (9) Pindolol (10) Labetalol.

Question 22

What are 5 clinical applications for beta-blockers? Where applicable, give the specific beta-blocker(s) used for a given application.

Answer 22

(1) Angina pectoris (2) MI (3) SVT (metoprolol, esmolol) (3) Hypertension (4) CHF (5) Glaucoma (timolol)

Question 23

What effects do beta blockers have in the context of angina pectoris?

Answer 23

Decrease heart rate and contractility, resulting in decreased O2 consumption

Question 24

What effects do beta blockers have in the context of MI? List 3 specific beta blockers for this application.

Answer 24

Beta-blockers (metoprolol, carvedilol, and bisoprolol) decrease mortality

Question 25

Again, what 2 beta blockers are used in the context of SVT? What effects do they have? To what drug class do they belong on the basis of such effects?

Answer 25

SVT (metoprolol, esmolol); Decrease AV conduction velocity (class II antiarrhythmic)

Question 26

What effects do beta blockers have in the context of hypertension, and why?

Answer 26

Decrease cardiac output, Decrease renin secretion (due to Beta 1-receptor blockade on JGA cells)

Question 27

What effect do beta blockers have in the context of CHF?

Answer 27

Slows progression of chronic failure

Question 28

Again, what beta blocker is used in the context of Glaucoma? What effect does it have?

Answer 28

Glaucoma (timolol); Decrease secretion of aqueous humor

Question 29

What are 5 major toxicities associated with beta-blockers? Where applicable, give the specific beta-blocker to which a toxicity pertains.

Answer 29

(1) Impotence (2) Cardiovascular adverse effects (bradycardia, AV blocks, CHF) (3) CNS adverse effects (seizures, sedation, sleep alterations), (4) Dyslipidemia (metoprolol), and (5) Asthmatics/COPDers (may cause exacerbation)

Question 30

In what patient population are beta-blockers avoided, and why?

Answer 30

Avoid in cocaine users due to risk of unopposed alpha-adrenergic receptor agonist activity

Question 31

What is a consideration of beta-blocker use in diabetics? Are beta-blockers contraindicated in diabetics?

Answer 31

Despite theoretical concern of masking hypoglycemia in diabetics, benefits likely outweigh risks; not contraindicated

Question 32

Name 5 Beta 1 -selective antagonists.

Answer 32

Beta 1-selective antagonists (Beta 1 > Beta 2) - (1) Acebutolol (partial agonist) (2) Atenolol (3) Betaxolol (4) Esmolol (5) Metoprolol; Think: “Selective antagonists mostly go from A to M (Beta 1 with 1st half of alphabet)

Question 33

Name 4 nonselective Beta antagonists.

Answer 33

Nonselective antagonists (Beta 1 = Beta) - (1) Nadolol (2) Pindolol (partial agonist) (3) Propanolol (4) Timolol; Think: “Nonselective antagonists mostly go from N to Z (Beta 2 with 2nd half of alphabet)”

Question 34

Name 2 nonselective alpha and beta antagonists.

Answer 34

Nonselective alpha and beta antagonists - (1) Carvedilol (2) Labetalol; Think: “Nonselectives alpha and beta antagonists have modified suffixes (instead of ‘-olol’)”

Question 35

On what receptors does Nebivolol, and how? What effect does this have?

Answer 35

Nebivolol combines cardiac-selective beta1-adrenergic blockage with stimulation of beta3-receptors, which activate nitric oxide synthase in the vasculature