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Questions and Answers
Which beta-blocker is considered non-selective, blocking both β1 and β2 receptors?
Which beta-blocker is considered non-selective, blocking both β1 and β2 receptors?
- Propranolol (correct)
- Bisoprolol
- Nebivolol
- Atenolol
A patient with a history of asthma is prescribed a beta-blocker. Which of the following agents would be most likely to cause bronchospasm?
A patient with a history of asthma is prescribed a beta-blocker. Which of the following agents would be most likely to cause bronchospasm?
- Atenolol
- Propranolol (correct)
- Bisoprolol
- Nebivolol
Which of the following beta-blockers is known for its ultrashort acting duration?
Which of the following beta-blockers is known for its ultrashort acting duration?
- Esmolol (correct)
- Carvedilol
- Metoprolol
- Atenolol
A patient with hypertension and a history of migraines is being considered for beta-blocker therapy. Which of the following beta-blockers would be most appropriate for both conditions?
A patient with hypertension and a history of migraines is being considered for beta-blocker therapy. Which of the following beta-blockers would be most appropriate for both conditions?
A patient with hyperthyroidism experiences tachycardia and anxiety. Which beta-blocker would be most appropriate to manage these symptoms?
A patient with hyperthyroidism experiences tachycardia and anxiety. Which beta-blocker would be most appropriate to manage these symptoms?
Which of the following is an absolute contraindication for the use of beta-blockers?
Which of the following is an absolute contraindication for the use of beta-blockers?
A patient with liver cirrhosis develops esophageal varices. Which beta-blocker is most appropriate to reduce portal blood flow in this patient?
A patient with liver cirrhosis develops esophageal varices. Which beta-blocker is most appropriate to reduce portal blood flow in this patient?
Beta-blockers are often used in the management of several conditions. Which is least likely to be treated with systemic beta-blockers?
Beta-blockers are often used in the management of several conditions. Which is least likely to be treated with systemic beta-blockers?
Which of the following statements best describes the mechanism of action of beta-blockers in reducing blood pressure?
Which of the following statements best describes the mechanism of action of beta-blockers in reducing blood pressure?
A patient taking a non-selective beta-blocker experiences hypoglycemia unawareness. What is the most likely mechanism?
A patient taking a non-selective beta-blocker experiences hypoglycemia unawareness. What is the most likely mechanism?
Beta-blockers can have several adverse effects. Which of the following is a common CNS-related side effect associated with beta-blocker use?
Beta-blockers can have several adverse effects. Which of the following is a common CNS-related side effect associated with beta-blocker use?
What is the primary reason for gradually withdrawing beta-blocker therapy rather than abruptly discontinuing it?
What is the primary reason for gradually withdrawing beta-blocker therapy rather than abruptly discontinuing it?
Which of the following best describes the effect of beta-blockers on aqueous humor secretion in the eye?
Which of the following best describes the effect of beta-blockers on aqueous humor secretion in the eye?
How do beta-blockers improve outcomes in patients with hypertrophic obstructive cardiomyopathy?
How do beta-blockers improve outcomes in patients with hypertrophic obstructive cardiomyopathy?
A patient with peripheral vascular disease (PVD) is being considered for beta-blocker therapy. Which statement regarding beta-blocker use is most accurate?
A patient with peripheral vascular disease (PVD) is being considered for beta-blocker therapy. Which statement regarding beta-blocker use is most accurate?
A patient with a known allergy to beta-blockers needs treatment for hypertension. Which of the following drug classes should be avoided?
A patient with a known allergy to beta-blockers needs treatment for hypertension. Which of the following drug classes should be avoided?
Which of the following beta-blockers also blocks alpha-1 receptors?
Which of the following beta-blockers also blocks alpha-1 receptors?
Pindolol is described as a partial agonist beta-blocker. What does this mean in terms of its pharmacological action?
Pindolol is described as a partial agonist beta-blocker. What does this mean in terms of its pharmacological action?
Which of the following is a therapeutic use for beta-blockers?
Which of the following is a therapeutic use for beta-blockers?
Beta-blockers can be used to treat cardiac arrythmias, by what mechanism?
Beta-blockers can be used to treat cardiac arrythmias, by what mechanism?
What is the mechanism of action of beta-blockers in the treatment of glaucoma?
What is the mechanism of action of beta-blockers in the treatment of glaucoma?
When are small doses of beta-blockers given to patients with chronic heart failure?
When are small doses of beta-blockers given to patients with chronic heart failure?
Which of the following is a beneficial effect of beta-blockers in heart failure?
Which of the following is a beneficial effect of beta-blockers in heart failure?
What is a common adverse effect of beta-blockers?
What is a common adverse effect of beta-blockers?
What effect do beta-blockers have on myocardial contractility?
What effect do beta-blockers have on myocardial contractility?
Flashcards
ẞ-blocker classifications?
ẞ-blocker classifications?
ẞ-blockers are classified into non-selective, selective, and those with VD action.
Non-selective ẞ-blockers?
Non-selective ẞ-blockers?
Block both ẞ1 and ẞ2 receptors. Examples include Propranolol, Pindolol and Timolol
Selective ẞ1 blockers?
Selective ẞ1 blockers?
Selectively block ẞ1 receptors. Examples include Atenolol and Bisoprolol
ẞ-blockers with VD action?
ẞ-blockers with VD action?
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Esmolol
Esmolol
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CVS effects of ẞ-blockers?
CVS effects of ẞ-blockers?
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How do beta-blockers lower BP?
How do beta-blockers lower BP?
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Respiratory effects of ẞ-blockers?
Respiratory effects of ẞ-blockers?
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Eye effects of ẞ-blockers?
Eye effects of ẞ-blockers?
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CNS effects of ẞ-blockers?
CNS effects of ẞ-blockers?
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Metabolic effects of Beta-blockers
Metabolic effects of Beta-blockers
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Labetalol
Labetalol
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ẞ-blockers treat hypertension?
ẞ-blockers treat hypertension?
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ẞ-blockers treat heart disease?
ẞ-blockers treat heart disease?
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ẞ-blockers treat arrhythmias?
ẞ-blockers treat arrhythmias?
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ẞ-blockers treat cardiomyopathy?
ẞ-blockers treat cardiomyopathy?
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ẞ-blockers treat heart failure?
ẞ-blockers treat heart failure?
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ẞ-blockers treat hyperthyroidism?
ẞ-blockers treat hyperthyroidism?
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ẞ-blockers treat varices?
ẞ-blockers treat varices?
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Adverse effects of Beta-blockers
Adverse effects of Beta-blockers
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Beta-blockers contraindications?
Beta-blockers contraindications?
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ẞ-blockers and vasospastic angina?
ẞ-blockers and vasospastic angina?
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ẞ-blockers and heart failure?
ẞ-blockers and heart failure?
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Sudden beta-blocker withdrawal?
Sudden beta-blocker withdrawal?
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Study Notes
Adrenergic Drugs: Beta Blockers
- Beta-blockers are sympatholytic drugs.
Classification of Beta-Receptor Blockers
- Non-selective beta-blockers (block B1 and B2 receptors) examples include: Propranolol, Pindolol, and Timolol.
- Propranolol has good CNS penetration and is metabolized in the liver.
- Selective beta-blockers (block B1 receptors) examples include: Atenolol, Bisoprolol, and Esmolol.
- Atenolol has limited CNS penetration and is mainly excreted by the kidney.
- Beta-blockers with vasodilating (VD) action examples include: Carvedilol (non-selective) and Nebivolol (highest B1 selectivity).
Pharmacological Effects of Beta Blockers in Regards to the Heart
- Beta-blockers reduce all cardiac properties by blocking B1 receptors and decreasing heart rate (bradycardia) and cardiac output (COP).
- They lower blood pressure through decreases in COP, renin release from the kidney (B1), and NA release and central sympathetic outflow.
- Some beta-blockers block vascular a1 receptors.
- Some increase the synthesis of PGE2 and PGI2 (VD).
Respiratory Effects of Beta Blockers
- Beta-blockers can produce bronchospasm, even selective B1 blockers at high doses, and are contraindicated in asthmatic patients.
Ocular Effects of Beta Blockers
- Beta-blockers like Timolol decrease intraocular pressure (IOP) by reducing aqueous humor secretion.
- Timolol can be absorbed after topical application.
CNS Effects of Beta Blockers
- Includes antianxiety effects, nightmares, and sexual dysfunction (via central and peripheral mechanisms).
Metabolic Effects of Beta Blockers
- Increases hypoglycemic effect of insulin due to decreased glycogenolysis in the liver (B2).
- Increases plasma K+ (hyperkalemia) in patients with renal failure.
- Elevates plasma triglycerides and lowers HDL.
Skeletal Muscle Effects of Beta Blockers
- Decreases essential tremors due to B2 block in skeletal muscles.
Other Specific Properties
- Pindolol is a partial agonist (does not cause excessive bradycardia).
- Esmolol is ultrashort acting (t 1/2 = 10 min) due to extensive hydrolysis by plasma esterases.
- Esmolol is given by intravenous infusion to control arrhythmia during surgery and emergency.
- Labetalol blocks B-receptors and a1-receptors (mixed blocker).
Therapeutic Uses
- Hypertension.
- Ischemic heart disease (classic angina & acute myocardial infarction).
- Decreases myocardial work & O2 demand.
- Redistribution of blood to the ischemic (subendocardial) regions.
- Cytoprotective effect.
- Cardiac arrhythmias (tachyarrhythmias), especially in thyrotoxic patients.
- Decreases A-V conduction
- Decreases automaticity.
- Decreases excitability (Propranolol: stabilizing action).
- I.V.I esmolol is used for acute arrhythmia during surgery.
- Hypertrophic obstructive cardiomyopathy caused by a thickening that impairs blood flow through aortic outlet expecially during exercise.
- Inhibiting the heart causes:
- Decreased HR and contractility (-ve inotropic).
- Increased outflow resistance to blood flow in aorta.
- Mild to moderate cases of chronic heart failure (HF)
- Reduces tachycardia & sympathetic overactivity.
- Reduces BP → ventricular strain associated with HF.
- Inhibits renin release → cardiac remodeling caused by RAAS.
- Bisoprolol, Metoprolol & Carvedilol produce the most useful effects in chronic HF; Carvedilol has VD & antioxidant properties}.
- Hyperthyroidism: Propranolol decreases tachycardia, anxiety & tremors due to sympathetic overactivity.
- Propranolol also prevents peripheral conversion of T4 into T3.
- Esophageal varices due to liver cirrhosis: Propranolol reduces portal & hepatic blood flow-> decreases COP & VC in the splanchnic vascular bed.
- Glaucoma (open angle): Use topical Timolol.
- Pheochromocytoma: Used in combination with alpha-blockers.
- Migraine prophylaxis: Use Propranolol.
- Anxiety: Use Propranolol.
Adverse Effects
- Tiredness & fatigue (most common) due to decreased COP & block of B2-mediated VD in skeletal muscles (non-selective agents).
- Bradycardia & decreased myocardial contractility (-Ve inotropic & chronotropic effect).
- Bronchospasm in susceptible individuals due to block of B2-receptors in the bronchi.
- Aggravation of peripheral ischemia (mainly non-selective agents).
- CNS effects: nightmares & depression.
- Sudden withdrawal can increase the risk of angina & arrhythmias due to adrenoceptor “supersensitivity."
- Gradual withdrawal is recommended after prolonged use.
Contraindications
- Absolute contraindications include Bronchial asthma, any degree of heart block, Vasospastic (Prinzmetal's) angina, acute heart failure & severe chronic heart failure, and sudden withdrawal after long-term use.
- Relative contraindications include peripheral vascular diseases (PVD), diabetes mellitus, athletes (strenuous sports), and hypotension.
Review Questions
- Q1: Which of the following is a selective B1 blocker?
- D. Bisoprolol.
- Q2: All of the following are uses of B blockers EXCEPT?
- C. Vasospastic (Prinzmetal's) angina.
- Q3: Which of the following is an absolute contraindication of B blockers?
- B. Bronchial asthma.
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