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Questions and Answers
What is the potential consequence of abruptly stopping non-selective beta blockers?
What is the potential consequence of abruptly stopping non-selective beta blockers?
Which of the following is true regarding cardio-selective beta blockers?
Which of the following is true regarding cardio-selective beta blockers?
What therapeutic use does propranolol have besides treating angina?
What therapeutic use does propranolol have besides treating angina?
Which of these side effects is associated with non-selective beta blockers?
Which of these side effects is associated with non-selective beta blockers?
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What characterizes esmolol among beta blockers?
What characterizes esmolol among beta blockers?
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What effect does beta-1 adrenergic receptor stimulation have on the heart?
What effect does beta-1 adrenergic receptor stimulation have on the heart?
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Which of the following is a classification of non-selective beta-blockers?
Which of the following is a classification of non-selective beta-blockers?
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What is one of the pharmacodynamic effects of non-selective beta-blockers on blood vessels?
What is one of the pharmacodynamic effects of non-selective beta-blockers on blood vessels?
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Which condition would contraindicate the use of non-selective beta-blockers due to potential exacerbation?
Which condition would contraindicate the use of non-selective beta-blockers due to potential exacerbation?
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What is the impact of non-selective beta-blockers on renal perfusion?
What is the impact of non-selective beta-blockers on renal perfusion?
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What metabolic effect is associated with non-selective beta-blockers?
What metabolic effect is associated with non-selective beta-blockers?
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Which beta-blocker is known for having intrinsic sympathomimetic activity?
Which beta-blocker is known for having intrinsic sympathomimetic activity?
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What is a therapeutic use of non-selective beta-blockers?
What is a therapeutic use of non-selective beta-blockers?
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What effect do partial agonists like pindolol and acebutolol have on heart rate and cardiac output compared to full antagonists?
What effect do partial agonists like pindolol and acebutolol have on heart rate and cardiac output compared to full antagonists?
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Which of the following is a benefit of using labetalol in the treatment of hypertension?
Which of the following is a benefit of using labetalol in the treatment of hypertension?
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What is a common adverse effect associated with the use of guanethidine?
What is a common adverse effect associated with the use of guanethidine?
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Which drug is classified as a selective β2 blocker and is not used clinically?
Which drug is classified as a selective β2 blocker and is not used clinically?
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How does reserpine affect blood pressure and heart rate?
How does reserpine affect blood pressure and heart rate?
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What is the primary mechanism by which cocaine exerts its pharmacological effects?
What is the primary mechanism by which cocaine exerts its pharmacological effects?
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Which statement accurately describes the effect of dual-action blockers like carvedilol?
Which statement accurately describes the effect of dual-action blockers like carvedilol?
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What is a unique aspect of labetalol's use in pregnant patients?
What is a unique aspect of labetalol's use in pregnant patients?
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Study Notes
Adrenergic Drugs
- Adrenergic drugs affect the sympathetic nervous system
- They play a crucial role in various physiological processes
Adrenergic Receptors: Location and Functions
- β₁: Located in the heart, increases heart rate, conductivity, and the force of contraction
- β₂: Located in bronchi, uterus, gastrointestinal tract (GIT), blood vessels (BV), and skeletal muscles; causes relaxation
- β₃: Located in adipose tissues, stimulates lipolysis
- α: Located in different organs; function varies depending on the specific alpha receptor subtype
Adrenergic Receptor Antagonists
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α-receptor antagonists: Nonselective, α₁-selective, α₂-selective
- Nonselective: phenoxybenzamine, phentolamine
- α₁-selective: prazosin, terazosin, doxazosin, alfuzosin, tamsulosin, urapidil, bunazosin
- α₂-selective: yohimbine
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β-receptor antagonists: Nonselective, β₁-selective, β₂-selective
- Nonselective: propranolol, nadolol
- β₁-selective: atenolol, metoprolol, esmolol, acebutolol
- Third-generation beta-blockers (β₁-selective): carvedilol, bisoprolol, nebivolol, labetalol
Beta-Blockers Classifications
- Nonselective: Block all β receptors (e.g., propranolol, nadolol)
- Selective β₁ (Cardio-selective): Block β₁ receptors (e.g., atenolol, metoprolol)
- Antagonists with partial agonist activity: Stimulate and block β receptors (e.g., pindolol, acebutolol)
- Antagonists of both α and β receptors (with VD activity): Block both α and β receptors with vasodilatory properties (e.g., labetalol, carvedilol)
Non-selective Beta-Blockers: Pharmacodynamics
- Heart (β₁): Negative inotropic, chronotropic, and dromotropic effects; decreases cardiac work and oxygen consumption, excitability, and automaticity
- Blood vessels (β₂): Reduction in vasodilation, unopposed α-mediated vasoconstriction
- Anti-hypertensive: Reduction in cardiac output (COP), sympathetic outflow from the central nervous system (CNS)
Non-Selective Beta-Blockers: Pharmacodynamics (Continued)
- Sodium (Na⁺) retention: Reduced blood pressure (BP) leads to reduced renal perfusion, increasing sodium retention and plasma volume
- Intraocular pressure (IOP): Reduction in aqueous humor synthesis
- Metabolism: Reduced glycogenolysis, lipolysis
Non-Selective Beta-Blockers: Pharmacodynamics (Continued)
- Central nervous system (CNS): Reduced anxiety, tremors (lipophilic beta-blockers)
- Local anesthetic action (some β-blockers): Sodium channel block, membrane stabilization, direct myocardial depression
Non-Selective Beta-Blockers: Therapeutic Uses
- Hypertension
- Angina: Decreases oxygen requirement of the heart muscle
- Myocardial infarction: Prevents further heart attacks
- Arrhythmias: Treats irregular heartbeats
- Glaucoma: Treatment of glaucoma
- Migraine headache
- Hyperthyroidism and Familial tremors
Non-Selective Beta-Blockers: Side Effects
- Bronchoconstriction: Potentially lethal in asthma and chronic obstructive pulmonary disease (COPD)
- Arrhythmias: Sudden withdrawal can worsen pre-existing conditions
- Sexual impairment: Impotence
- Hypoglycemia: Blocks manifestations and recovery in type 1 diabetes
β₁-Selective Blocker (Cardio-selective)
- Examples: Atenolol, acebutolol, metoprolol, esmolol
- Advantages: Less effect on pulmonary functions, peripheral resistance, and glucose homeostasis
- Disadvantages: Cardioselectivity can be lost at high doses
β₁-Selective Blocker (Cardio-selective) (Continued)
- Esmolol: Ultra-short-acting beta-blocker, destroyed by plasma esterase, administered intravenously
- Uses: Hypertension (with monitoring in asthma patients), diabetic hypertensive patients, acute or short-term hypertension and arrhythmias during procedures/emergencies
Antagonists with Partial Agonist Activity
- Examples: Pindolol, acebutolol
- Mechanism: Stimulate β receptors first, then block them
- Advantages: Less decrease in heart rate (HR) and cardiac output (CO), fewer disturbances in glucose and lipid metabolism
Antagonists of Both α and β Receptors
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Examples: Labetalol, carvedilol
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Mechanism: Produce vasodilation via α1 blockade, useful in hypertension with peripheral vascular resistance (PVD)
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Adverse effects: Orthostatic hypotension, dizziness
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β₁ Antagonists: Uses: Useful in elderly hypertensives, alternative to methyldopa in pregnancy-induced hypertension, rapid decrease in blood pressure (BP) in emergencies.
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β₁ Antagonists: Carvedilol's uses: Decreases lipid peroxidation and vessel wall thickening, useful in heart failure (HF)
Butaxamine
- Selective β₂ blocker, not used clinically
Drugs Affecting Neurotransmitter Release or Uptake
- Reserpine: Plant alkaloid; prevents storage of norepinephrine (NE), dopamine, and 5-hydroxytryptamine (5-HT) in vesicles; inhibits Mg²⁺/ATP-dependent transport; used to treat hypertension resistant to other drugs
- Guanethidine: Blocks release of NE; displaces NE from storage vesicles; causes orthostatic hypotension, male sexual dysfunction; can lead to hypertensive crises in patients with pheochromocytoma
- Cocaine: Local anesthetic; inhibits reuptake of both epinephrine and NE; increases the action of catecholamines
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Description
This quiz explores the functions and effects of adrenergic drugs on the sympathetic nervous system. It covers the locations and roles of various adrenergic receptors and details about receptor antagonists, including specific drugs and their classifications.
