Beta Blockers (Sympatholytic Drugs) Flashcards by Allie Moses

What is the prototype beta blocker?

Propranolol

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What is properties of Propranolol?

Nonselective, pure β1-β2 antagonist activity

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What is the effects of beta 1 blockade of Propranolol?

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

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

Chronotropic effects longer than inotropic

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What effect is B2 blockade with Propranolol?

β2 increase PVR (coronary vascular resistance)

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What is the net effect of Propranolol?

may relieve myocardial ischemia

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What is the target goal HR of Propranolol?

Dosed to a clinical goal of HR 55-60

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What has replaced Propranolol in anesthesia?

Been replaced mostly by esmolol for anesthesia purposes

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What is impacts Propranolol?

Significant hepatic first pass effect

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What is the protein binding of Propranolol?

protein binding (90-95%)

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What affect does heparin have with Propranolol?

Heparin increases plasma concentration

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What affects the pharmokinetics of Propranolol?

Affected by changes in hepatic blood flow and enzyme activity

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What is true about plasma concentration of Propranolol?

Plasma concentration does not reflect therapeutic effects

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What is the clearance of Propranolol?

Hepatic clearance with active metabolite: 4-hydroxypropranolol
More of issue after oral dose

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What impact does Propranolol have with local anesthetics?

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

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What local anesthetic has the biggest impact of Propranolol?

Bupivacaine up to 35% decrease in clearance

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What increases the bioavailability of Propranolol?

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

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What is Nadolol?

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

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What is the elimination of Nadolol with renal failure?

increased elimination in renal failure

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

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

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What is Metoprolol?

Selective β-1 adrenergic blocker

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What is true about the safety profile of Metoprolol?

Less adverse effects for obstructive airway disease, PVD, hypoglycemics

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What is the purpose of Metoprolol with anesthesia?

Anesthesia: for controlling heart rate without affecting B/P

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What are the clinical effects of Metoprolol?

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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What is the dose of Metoprolol?

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

When does Metoprolol peak?

Peaks in approximately 10 min

What is the elimination half time of Metoprolol?

3-4 hours

What is the volume of distribution of Metoprolol?

High Vd (5-6 L/kg)

What is Nebivolol?

Selective β-1 antagonist

What is the elimination half time of Nebivolol?

12-19 hrs

What is the MOA of Bisoprolol?

selective β-1 antagonist

What is Bisoprolol used to treat?

used to treat essential HTN

What are the effects of Bisoprolol?

negative chronotropic effects

What is the MOA of Betaxolol?

Cardioselective β-1 antagonist

What is the elimination half time of Betaxolol?

11-22 hrs

What is the use of Betaxolol?

used to treat HTN, gtts for glaucoma

What is the MOA of Atenolol?

Most selective β-1

What is the use for Atenolol?

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

What is the excretion of Atenolol?

85-100% excreted unchanged in the urine

What is the elimination half time of Atenolol?

elimination half-time 6-7 hrs

What is the important about Atenolol use with diabetics?

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

What is the MOA of Esmolol?

Cardioselective β-1 antagonist

Why is Esmolol commonly used in anesthesia?

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

What effect Esmolol have on heart rate?

Controls heart rate whereas lidocaine or fentanyl does not with intubation

What are the uses for Esmolol?

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

When is Esmolol not an appropriate treatment?

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

Why is Esmolol ideal for anesthesia?

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

What is the dose of Esmolol?

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

What is the formularies for Esmolol?

IV only, pain on injection

What is the metabolism of Esmolol?

* \*\*\*Rapid hydrolysis by plasma red blood cell esterases (NOT plasma pseudocholinesterase) * no renal or hepatic metabolism

What is the effect of Esmolol with pregnant woman?

Limited transfer across placenta

What is the elimination time of Esmolol?

Elimination half-time = 9 minutes

What is the side effects of Esmolol?

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

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

short duration of action

What is the MOA of Labetalol?

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

What is the potency ratio of Labetalol?

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

What is elimination of Labetalol?

Elimination half time is 5-8 hrs

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

prolonged with liver disease, unchanged by renal disease

What are the CV effects of Labetalol?

α-1 / β -2 blockade: * decrease in BP * reflex tachycardia attenuated by β-blockade * CO unchanged

When is the max therapeutic effect of Labetalol?

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

What is the uses of Labetalol?

hypertensive emergencies however aggressive dosing may result in excessive hypotension.

What is the anesthesia use for Labetalol?

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

What is the most common side effect of Labetalol?

Orthostatic hypotension

What other possible adverse effects of Labetalol?

* Bronchospasm possible with susceptible patients * CHF * bradycardia * heart block

What is the MOA of Carvedilol (Coreg)?

Nonselective β antagonist with α-1 blocking activity

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

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

What are the properties of Carvedilol (Coreg)?

Vasodilator and antioxidant properties

What is the clinical use of Carvedilol (Coreg)?

Treat mild to moderate CHF, essential HTN

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

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

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

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

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

resulting decrease in systemic BP and cardiac output

Beta Blockers (Sympatholytic Drugs) Flashcards

(71 cards)