Beta Blockers (Sympatholytic Drugs) Flashcards

1
Q

What is the prototype beta blocker?

A

Propranolol

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2
Q

What is properties of Propranolol?

A

Nonselective, pure β1-β2 antagonist activity

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3
Q

What is the effects of beta 1 blockade of Propranolol?

A

β1 decreases HR and contractility (decreased CO which can lead to Na+ retention)

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4
Q

What is true about the chronotropic vs the inotropic effects of Propranolol?

A

Chronotropic effects longer than inotropic

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5
Q

What effect is B2 blockade with Propranolol?

A

β2 increase PVR (coronary vascular resistance)

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6
Q

What is the net effect of Propranolol?

A

may relieve myocardial ischemia

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7
Q

What is the target goal HR of Propranolol?

A

Dosed to a clinical goal of HR 55-60

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8
Q

What has replaced Propranolol in anesthesia?

A

Been replaced mostly by esmolol for anesthesia purposes

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9
Q

What is impacts Propranolol?

A

Significant hepatic first pass effect

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10
Q

What is the protein binding of Propranolol?

A

protein binding (90-95%)

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11
Q

What affect does heparin have with Propranolol?

A

Heparin increases plasma concentration

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12
Q

What affects the pharmokinetics of Propranolol?

A

Affected by changes in hepatic blood flow and enzyme activity

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13
Q

What is true about plasma concentration of Propranolol?

A

Plasma concentration does not reflect therapeutic effects

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14
Q

What is the clearance of Propranolol?

A
  • Hepatic clearance with active metabolite: 4-hydroxypropranolol
  • More of issue after oral dose
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15
Q

What impact does Propranolol have with local anesthetics?

A
  • Decreases clearance of amide local anesthetics
  • Mainly as a result of propranolol-induced decreases in metabolism
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16
Q

What local anesthetic has the biggest impact of Propranolol?

A

Bupivacaine up to 35% decrease in clearance

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17
Q

What increases the bioavailability of Propranolol?

A

Decreased pulmonary first pass uptake of fentanyl in patients tx chronically w/propranolol; thus increasing bioavailability 2-4x

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18
Q

What is Nadolol?

A

long acting nonselective β-blocker (once a day administration)

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19
Q

What is the elimination of Nadolol with renal failure?

A

increased elimination in renal failure

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20
Q

What is Timolol? What is important to know about this medication?

A

used as eye drops for glaucoma that can have systemic effects that can be resistant to atropine

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21
Q

What is Metoprolol?

A

Selective β-1 adrenergic blocker

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22
Q

What is true about the safety profile of Metoprolol?

A

Less adverse effects for obstructive airway disease, PVD, hypoglycemics

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23
Q

What is the purpose of Metoprolol with anesthesia?

A

Anesthesia: for controlling heart rate without affecting B/P

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24
Q

What are the clinical effects of Metoprolol?

A
  • Bronchodilation, vasodilation, and metabolic effect of β-2 intact
  • Dose related, problematic at larger doses but more easily reversible with β-2 agonists such as terbutaline
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25
Q

What is the dose of Metoprolol?

A

1- 15 mg IV (2.5- 5 mg q 5 min to 15 mg total or desired effect)

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26
Q

When does Metoprolol peak?

A

Peaks in approximately 10 min

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27
Q

What is the elimination half time of Metoprolol?

A

3-4 hours

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28
Q

What is the volume of distribution of Metoprolol?

A

High Vd (5-6 L/kg)

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29
Q

What is Nebivolol?

A

Selective β-1 antagonist

30
Q

What is the elimination half time of Nebivolol?

A

12-19 hrs

31
Q

What is the MOA of Bisoprolol?

A

selective β-1 antagonist

32
Q

What is Bisoprolol used to treat?

A

used to treat essential HTN

33
Q

What are the effects of Bisoprolol?

A

negative chronotropic effects

34
Q

What is the MOA of Betaxolol?

A

Cardioselective β-1 antagonist

35
Q

What is the elimination half time of Betaxolol?

A

11-22 hrs

36
Q

What is the use of Betaxolol?

A

used to treat HTN, gtts for glaucoma

37
Q

What is the MOA of Atenolol?

A

Most selective β-1

38
Q

What is the use for Atenolol?

A
  • Used to prevent recurrent supraventricular arrythmias, HTN, stable angina.
  • Also prophylactic use for cardiac patients undergoing noncardiac procedures (shown to decrease mortality and complications)
39
Q

What is the excretion of Atenolol?

A

85-100% excreted unchanged in the urine

40
Q

What is the elimination half time of Atenolol?

A

elimination half-time 6-7 hrs

41
Q

What is the important about Atenolol use with diabetics?

A

Prolonged anti-HTN effects, used cautiously with diabetics as does not induce β-antagonist induced hypoglycemia

42
Q

What is the MOA of Esmolol?

A

Cardioselective β-1 antagonist

43
Q

Why is Esmolol commonly used in anesthesia?

A

Commonly used in anesthesia to attenuate the sympathomimetic responses to noxious stimulation (such as intubation, rigid bronch, extubation)

44
Q

What effect Esmolol have on heart rate?

A

Controls heart rate whereas lidocaine or fentanyl does not with intubation

45
Q

What are the uses for Esmolol?

A

Pheochromocytoma, thyrotoxicosis, HTN crisis, etc. (sympathetic overdrive)

46
Q

When is Esmolol not an appropriate treatment?

A

β-blockers not best treatment for excess sympathetic activity seen with cocaine or epinephrine given the inability of the heart to compensate for the increased afterload (take away HR, contractility)- better treated with dilators as SNP or NTG

47
Q

Why is Esmolol ideal for anesthesia?

A

Ideal for anesthesia given rapid onset (full therapeutic effects within 5 min) and short duration (10-30 min)

48
Q

What is the dose of Esmolol?

A

0.5 mg/kg bolus/ Infusion (load 0.5-1 mg/kg followed by 50-300 mcg/kg/min

49
Q

What is the formularies for Esmolol?

A

IV only, pain on injection

50
Q

What is the metabolism of Esmolol?

A
  • ***Rapid hydrolysis by plasma red blood cell esterases (NOT plasma pseudocholinesterase)
  • no renal or hepatic metabolism
51
Q

What is the effect of Esmolol with pregnant woman?

A

Limited transfer across placenta

52
Q

What is the elimination time of Esmolol?

A

Elimination half-time = 9 minutes

53
Q

What is the side effects of Esmolol?

A
  • All similar for the β-blockers (magnitude dependent on selectivity and dose)
  • hypotension
  • heart block
  • bradycardia
  • bronchospasm
  • hypoglycemia
  • Extravasation can cause tissue necrosis
54
Q

What is the advantage of the side effect profile of Esmolol?

A

short duration of action

55
Q

What is the MOA of Labetalol?

A
  • Combined selective α and nonselective β receptor antagonists
  • Presynaptic α-2 effects spared (NE can inhibit further release of catecholamines)
56
Q

What is the potency ratio of Labetalol?

A

7:1 – β to α blocking ratio with IV use

57
Q

What is elimination of Labetalol?

A

Elimination half time is 5-8 hrs

58
Q

What is the effect of renal and liver disease on Labetalol?

A

prolonged with liver disease, unchanged by renal disease

59
Q

What are the CV effects of Labetalol?

A

α-1 / β -2 blockade:

  • decrease in BP
  • reflex tachycardia attenuated by β-blockade
  • CO unchanged
60
Q

When is the max therapeutic effect of Labetalol?

A

5-10 min (0.1-0.5 mg/kg)

61
Q

What is the uses of Labetalol?

A

hypertensive emergencies however aggressive dosing may result in excessive hypotension.

62
Q

What is the anesthesia use for Labetalol?

A

Intraop anesthesia for a combined effect of heart rate and BP control that can result from surgical stimulation pre-existing HTN

63
Q

What is the most common side effect of Labetalol?

A

Orthostatic hypotension

64
Q

What other possible adverse effects of Labetalol?

A
  • Bronchospasm possible with susceptible patients
  • CHF
  • bradycardia
  • heart block
65
Q

What is the MOA of Carvedilol (Coreg)?

A

Nonselective β antagonist with α-1 blocking activity

66
Q

What is the elimination half-time of Carvedilol (Coreg)?

A

Extensive protein binding with elimination half-time 7-10 hrs

67
Q

What are the properties of Carvedilol (Coreg)?

A

Vasodilator and antioxidant properties

68
Q

What is the clinical use of Carvedilol (Coreg)?

A

Treat mild to moderate CHF, essential HTN

69
Q

What affect can be seen with inhaled or IV anesthetics and beta-adrenergic blocking drugs?

A

Myocardial depression produced by inhaled or injected anesthetics could be additive w/depression produced by beta-adrenergic blocking drugs (importance of titrating anesthetic agents)

70
Q

What is the effect of ketamine with β-Adrenergic Receptor Antagonists?

A

Ketamine administration or presence of hypercarbia (both stimulate SNS activity) in conjunction with administration of a beta-adrenergic receptor antagonist drug may unmask direct negative inotropic effects of concomitantly administered anesthetics w/ resulting decrease in systemic BP and cardiac output

71
Q

What is the end result of ketamine and β-Adrenergic Receptor Antagonists?

A

resulting decrease in systemic BP and cardiac output