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Cardio Drugs > Adrenergic Agonists and Antagonists > Flashcards

Adrenergic Agonists and Antagonists Flashcards

1
Q

What are the endogenous direct-acting adrenergic catecholamines?

A

Epinephrine, Norepinephrine, Dopamine (affect alpha and beta receptors)

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2
Q

What receptors does Epinephrine act on? What cardiovascular effects does it have?

A

B1=B2; A1=A2; beta effects are higher affinity
CV effects: B1-positive inotrope and chronotrope -> incr. CO and SBP
-Slight reduction in systemic vasc. resistance (B2 vasodilates > alpha 1 vasoconstriction)
-Net effect: * wide pulse pressure

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3
Q

Clinical uses for epinephrine

A
  • # 1 for anaphylaxis (IV)
  • Cardiac arrest
  • Asthma-> bronchospasm
  • Local anesthetic-> alpha causes vasoconstriction -> used in combo w/ lidocaine-> vasoconstriction keeps LA in area
  • Open-angle glaucoma
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4
Q

Epinephrine Toxicities

A

Palpitations, HTN, Tremor, Anxiety

-Do not give to ppl w/ hyperthyroidism or pts who are on beta blockers

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5
Q

What receptors does NE work on? What CV effects does it have?

A

A1=A2; B1»» B2
-CV effects: @ low doses negligible; increased systemic vascular resistance-> reflex drop in HR (baroreceptor effect b/c MAP=CO x TPR)

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6
Q

Clinical Uses for Norepinephrine

A

-#1 Hypotension in sepsis (IV) also cardiogenic shock

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7
Q

Dopamine Effects are dose dependent explain

A
  • ***@ low doses-> Dopamine acts on DA1 Rs in kidney-> induces diuresis
  • Activation of B1 receptors in the heart produces an increase in contractile force
  • Increase in peripheral resistance via alpha receptors-> increases afterload -> increases HR -> arrhythmias
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8
Q

Clinical Uses for Dopamine (IV)

A
  • Hypotension **

- Low CO via B1 receptors

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9
Q

Dopamine Toxicity:

A

Arrhythmia (both ventricular and supra ventricular); Wide QRS; Angina

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10
Q

What are the receptor-specific adrenergic agonists?

A

-Phenylephrine, clonidine, dobutamine, isoproteronol, albuterol

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11
Q

What is Phenylephrine? What does it stimulate and its effects?

A
  • Alpha-1 adrenergic agonists
  • Increased arterial vasoconstriction(increase BP)
  • Decreased venous capacitance
  • Reflex decrease in HR
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12
Q

Why do we use Phenylephrine?

A
  • # 2 for Hypotension (IV) if can’t use NE

- Rhinitis; mydriatic

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13
Q

What is Clonidine? What are it’s effect?

A
  • Alpha-2 adrenergic agonists

- Decreases SNS outflow-> decreases HR, decreases systemic vascular resistance, increases capacitance

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14
Q

Why do we use Clonidine?

A

Uses: Hypertension, anxiolytic, ADHD

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15
Q

Describe Clonidine Toxicity?

A

Dry mouth, sedation, depression, rebound HTN

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16
Q

What is Isoproterenol? What does it affect and how do you give it?

A
  • Nonselective beta-adrenergic agonists
  • IV only
  • B1=B2 effects
  • B1=increases HR, contractility, conduction velocity
  • B2=decreased peripheral vascular resistance (afterload)
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17
Q

What is Isoproterenol used for?

A

Stokes-Adams attack**(Syncope due to slow or absent pulse), cardiac arrest, heart block, evaluation of tachyarrhythmia

18
Q

Isoproterenol toxicity

A

Tachycardia, hypertension, dysrhythmia

-Increases myocardial oxygen demand

19
Q

What is Dobutamine? How can we administer it?

A
  • Beta-1 selective adrenergic agonists
  • IV only
  • Beta 1 selective but also (-) isomer -> some alpha
  • Increased contractility > chronotropic effect
  • Alpha 1 maintains peripheral resistance
20
Q

What is Dobutamine used for?

A

-#1 drug for cardiogenic shock w/ **maintained BP

21
Q

Dobutamine toxicity

A

Tachyarrhythmia, PVCs, hypertension

22
Q

What are the alpha- blockers?

A

Non-selective-irreversible: Phenoxybenzamine
Non-selective-Reversible: Phentolamine
Alpha1-selective: Prazosin, Terazosin, Doxazosin, Tamulosin

23
Q

What is Phenoxybenzamine?

A

Non-selective alpha antagonist

24
Q

What effects does Phenoxybenzamine have?

A
  • Nonselective a1 and a2 blockade (a1>a2)
  • **only irreversible agent-> blockade lasts 14-48hrs
  • Blocks NE reuptake at presynaptic terminals
25
Q

When do we use Phenoxybenzamine?

A

Treatment of Pheochromocytoma-> tumor that occur in the adrenal medullaris-> excess prod. of catecholamines

26
Q

Adverse effects of Phenoxybenzamine

A

Postural hypotension, reflex tachycardia, nasal stiffness, fatigue, and nausea

27
Q

What is Prazosin?

A

Alpha 1 selective antagonist

28
Q

What are Prazosin’s effects?

A
  • Highly selective for alpha 1
  • Relaxes arterial and venous smooth muscle
  • Relaxes smooth muscle in the prostate
  • metabolized in liver w/ 3H half-life
  • **Tamulosin: “Uroselective”-> more selective for BPH
29
Q

When do we use Prazosin?

A

Hypertension (not 1st line) and Benign Prostate Hyperplasia

30
Q

Adverse effects of Prazosin

A
  • Orthostatic hypotension -> usually w/ 1st dose
  • Dizziness; headache
  • Drowsiness
  • Ejaculation problems
31
Q

What are the beta-adrenergic antagonists?

A
  1. ) non-selective: propranolol, nadolol, pindolol, sotalol
  2. ) Beta 1 (cardio)-selective antagonists: Atenolol, metoprolol, acebutolol, esmolol, nebivolol
  3. ) Antagonists action against alpha1, B1, and B2: Carvedilol, Labetolol
32
Q

What are the pharmacokinetics of beta blockers?

A
  • limited bioavailability when taken orally
  • large volume of distribution
  • Most drugs are metabolized in liver-except nadolol
33
Q

CV effects of beta blockers

A
  • *Lowering of high BP
  • Negative chronotrope
  • Negative inotrope
34
Q

What are non CV effects of Beta blockers?

A
  • Respiratory system: Bronchoconstrction: even w/ beta1 selective drugs; Contraindicated w/ severe obstructive disease (FEV1 <50% PV)
  • Metabolic and endocrine effects: block lipolysis leading to increased VLDL
  • Eye: Reduce intraocular pressure
35
Q

What are some therapeutic uses for beta blockers?

A
  • HTN **(Not recommended as 1st line therapy)
  • Myocardial infarction-propanolol in acute STEMI-> b/c decreases myocardial O2 demand
  • Heart failure: Metoprolol in symptomatic heart failure (reduced EF)
  • *Hyperthyroidism b/c of it’s high SNS tone; excess catecholamines
36
Q

What are adverse cardiac effects of beta blockers?

A
  • Drug rebound-> can precipitate acute MI in patients w/ CAD; ventricular arrhythmia
  • CHF exacerbation-> pts with acute decompensated heart failure (HF, low BP and pulmonary edema)
  • Bradyarrhythmia- presence of AV conduction defect can lead to serious bradyarrhythmia
37
Q

What are some adverse non-cardiac effects of beta blockers?

A
  • *Bronchoconstriction
  • Hyperglycemia
  • Depression,fatigue, sexual dysfunction ** very low risk
  • Weight gain
38
Q

When would we use Beta1 (cardio)-selective antagonists?

A

-Preferred in patients w/ asthma, COPD, DM

39
Q

What are examples of Beta 1 antagonists?

A
  • Atenolol, metoprolol
  • Acebutolol: Partial agonist activity
  • Esmolol: Parenteral, ULTRA short acting
40
Q

Why is Nebivolol unique?

A
  • beta 1 antagonist
  • Most highly selective B1 agent
  • Vasodilatory effects via NO release
    • Does not affect lipid profile or glycemic control
41
Q

Antagonists action against A1, B1, and B2

A

Carvediol-used in CHF and HTN

-Best beta blocker in diabetic patients

Cardio Drugs (5 decks)

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