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Questions and Answers
Which of the following physiological responses would be expected from blocking α1 adrenergic receptors?
Which of the following physiological responses would be expected from blocking α1 adrenergic receptors?
- Decreased pupillary dilation (mydriasis)
- Increased vasoconstriction in the skin and splanchnic regions (correct)
- Increased contraction of the bladder sphincter
- Increased force of heart contraction
A patient is experiencing excessive sympathetic stimulation. Which class of drugs would be MOST appropriate to decrease this activity?
A patient is experiencing excessive sympathetic stimulation. Which class of drugs would be MOST appropriate to decrease this activity?
- Cholinergic agonists
- Adrenergic agonists (correct)
- Histamine releasers
- Adrenergic antagonists
A drug that blocks or opposes the effects of an agonist is best described as a(n):
A drug that blocks or opposes the effects of an agonist is best described as a(n):
- Receptor antagonist
- Ion channel activator
- Receptor agonist (correct)
- Enzyme inhibitor
Which physiological response is NOT associated with activation of β2 adrenergic receptors?
Which physiological response is NOT associated with activation of β2 adrenergic receptors?
A patient with a catecholamine-secreting tumor is undergoing surgery. Which drug would be MOST useful in preventing a hypertensive crisis during the procedure?
A patient with a catecholamine-secreting tumor is undergoing surgery. Which drug would be MOST useful in preventing a hypertensive crisis during the procedure?
Why is phenoxybenzamine useful during the surgical removal of a pheochromocytoma?
Why is phenoxybenzamine useful during the surgical removal of a pheochromocytoma?
Phentolamine is used to treat extravasation of dopamine or norepinephrine. How does phentolamine work in this scenario?
Phentolamine is used to treat extravasation of dopamine or norepinephrine. How does phentolamine work in this scenario?
A patient is prescribed prazosin. What condition is prazosin NOT typically used to treat?
A patient is prescribed prazosin. What condition is prazosin NOT typically used to treat?
What distinguishes tamsulosin from other alpha-1 antagonists?
What distinguishes tamsulosin from other alpha-1 antagonists?
What is the primary mechanism of action of yohimbine?
What is the primary mechanism of action of yohimbine?
A patient with stage fright needs a medication to manage the physical symptoms of anxiety, such as sweating and tachycardia. Which drug would be MOST appropriate?
A patient with stage fright needs a medication to manage the physical symptoms of anxiety, such as sweating and tachycardia. Which drug would be MOST appropriate?
Why are nonselective beta antagonists contraindicated in patients with asthma or COPD?
Why are nonselective beta antagonists contraindicated in patients with asthma or COPD?
Timolol eyedrops are prescribed for a patient with glaucoma. What is the mechanism of action of timolol in this scenario?
Timolol eyedrops are prescribed for a patient with glaucoma. What is the mechanism of action of timolol in this scenario?
A cardiologist is choosing a beta blocker for a patient with hypertension who also has mild asthma. Which beta blocker would be MOST appropriate?
A cardiologist is choosing a beta blocker for a patient with hypertension who also has mild asthma. Which beta blocker would be MOST appropriate?
Nebivolol has a unique mechanism of action compared to other beta-1 blockers. What additional effect does nebivolol have that contributes to its antihypertensive properties?
Nebivolol has a unique mechanism of action compared to other beta-1 blockers. What additional effect does nebivolol have that contributes to its antihypertensive properties?
A pregnant patient with hypertension requires pharmacological treatment. Which medication would be MOST appropriate?
A pregnant patient with hypertension requires pharmacological treatment. Which medication would be MOST appropriate?
What distinguishes carvedilol from labetalol, even though both are alpha and beta blockers?
What distinguishes carvedilol from labetalol, even though both are alpha and beta blockers?
To predict the net effect of an adrenergic antagonist, what is the FIRST step one should consider?
To predict the net effect of an adrenergic antagonist, what is the FIRST step one should consider?
A patient with diabetes is taking a non-selective beta blocker. What potential risk should be considered, and why?
A patient with diabetes is taking a non-selective beta blocker. What potential risk should be considered, and why?
A patient presents with cold and painful fingers that turn white in response to cold exposure. What treatment option would directly address the underlying cause of these symptoms?
A patient presents with cold and painful fingers that turn white in response to cold exposure. What treatment option would directly address the underlying cause of these symptoms?
A patient with BPH also has hypertension, and the physician wants to choose a single medication to treat both conditions. Which of the medications would be MOST appropriate?
A patient with BPH also has hypertension, and the physician wants to choose a single medication to treat both conditions. Which of the medications would be MOST appropriate?
A researcher is investigating a new drug that selectively blocks alpha-2 adrenergic receptors. What effect would this drug be expected to have on sympathetic nervous system activity?
A researcher is investigating a new drug that selectively blocks alpha-2 adrenergic receptors. What effect would this drug be expected to have on sympathetic nervous system activity?
A patient received an overdose of epinephrine resulting in dangerously high blood pressure. Which of the following medications should be administered FIRST?
A patient received an overdose of epinephrine resulting in dangerously high blood pressure. Which of the following medications should be administered FIRST?
A patient is experiencing urinary retention due to benign prostatic hyperplasia (BPH). Which receptor type is primarily responsible for the prostate smooth muscle contraction which is causing the urinary retention?
A patient is experiencing urinary retention due to benign prostatic hyperplasia (BPH). Which receptor type is primarily responsible for the prostate smooth muscle contraction which is causing the urinary retention?
A researcher is studying the effects of a new beta-blocker that has shown promise in treating hypertension. They notice that, in addition to blocking beta-1 receptors, the drug also seems to have effects on vascular smooth muscle. Which of the following would MOST explain that effect?
A researcher is studying the effects of a new beta-blocker that has shown promise in treating hypertension. They notice that, in addition to blocking beta-1 receptors, the drug also seems to have effects on vascular smooth muscle. Which of the following would MOST explain that effect?
A patient with hypertension has a history of asthma. Which beta-blocker would be LEAST appropriate for this patient?
A patient with hypertension has a history of asthma. Which beta-blocker would be LEAST appropriate for this patient?
A patient with a history of myocardial infarction (heart attack) is being discharged from the hospital. Which beta-blocker would be MOST appropriate for reducing mortality and symptoms during recovery?
A patient with a history of myocardial infarction (heart attack) is being discharged from the hospital. Which beta-blocker would be MOST appropriate for reducing mortality and symptoms during recovery?
A person is about to give a speech in front of a large crowd and is concerned about experiencing performance anxiety characterized by sweating and tachycardia. What would be the MOST appropriate medication to manage these symptoms?
A person is about to give a speech in front of a large crowd and is concerned about experiencing performance anxiety characterized by sweating and tachycardia. What would be the MOST appropriate medication to manage these symptoms?
Adrenergic antagonists are generally drugs that cause:
Adrenergic antagonists are generally drugs that cause:
Which of the following is a physiological effect typically associated with blocking alpha-2 adrenergic receptors?
Which of the following is a physiological effect typically associated with blocking alpha-2 adrenergic receptors?
A patient presents with hypertension and is also diagnosed with benign prostatic hyperplasia (BPH). Which alpha-1 selective antagonist would be MOST appropriate to treat both conditions simultaneously?
A patient presents with hypertension and is also diagnosed with benign prostatic hyperplasia (BPH). Which alpha-1 selective antagonist would be MOST appropriate to treat both conditions simultaneously?
A patient with pre-existing hypotension needs treatment with an adrenergic antagonist. Which of the following would be LEAST appropriate?
A patient with pre-existing hypotension needs treatment with an adrenergic antagonist. Which of the following would be LEAST appropriate?
A researcher aims to study the effects of selective alpha-1 adrenergic receptor blockade on blood pressure regulation. Which drug would be MOST suitable for this purpose?
A researcher aims to study the effects of selective alpha-1 adrenergic receptor blockade on blood pressure regulation. Which drug would be MOST suitable for this purpose?
A patient is inadvertently administered an excessive dose of a beta-2 adrenergic agonist. Which of the following drugs would be MOST appropriate to counteract the resulting bronchodilation and tachycardia?
A patient is inadvertently administered an excessive dose of a beta-2 adrenergic agonist. Which of the following drugs would be MOST appropriate to counteract the resulting bronchodilation and tachycardia?
A patient with hypertension is also diagnosed with glaucoma. Which of the following beta-blockers, administered as eye drops, would be MOST appropriate for managing both conditions?
A patient with hypertension is also diagnosed with glaucoma. Which of the following beta-blockers, administered as eye drops, would be MOST appropriate for managing both conditions?
A patient with type 1 diabetes is prescribed a non-selective beta-blocker for hypertension. What is the MOST important consideration in managing this patient?
A patient with type 1 diabetes is prescribed a non-selective beta-blocker for hypertension. What is the MOST important consideration in managing this patient?
Following a myocardial infarction, a patient is started on metoprolol. What is the MOST likely reason for including this medication in the patient's regimen?
Following a myocardial infarction, a patient is started on metoprolol. What is the MOST likely reason for including this medication in the patient's regimen?
A patient with Raynaud's syndrome experiences severe vasospasms in their fingers upon exposure to cold. Which medication would be MOST appropriate to manage their symptoms by promoting vasodilation?
A patient with Raynaud's syndrome experiences severe vasospasms in their fingers upon exposure to cold. Which medication would be MOST appropriate to manage their symptoms by promoting vasodilation?
A pregnant patient with chronic hypertension requires pharmacological treatment that poses minimal risk to the fetus. Which of the following adrenergic antagonists would be MOST appropriate?
A pregnant patient with chronic hypertension requires pharmacological treatment that poses minimal risk to the fetus. Which of the following adrenergic antagonists would be MOST appropriate?
A patient taking a non-selective beta-blocker begins to experience increased airway resistance and shortness of breath. Which of the following mechanisms BEST explains these adverse effects?
A patient taking a non-selective beta-blocker begins to experience increased airway resistance and shortness of breath. Which of the following mechanisms BEST explains these adverse effects?
A researcher is investigating a new drug with potential alpha-1 adrenergic antagonist activity. Which of the following effects would BEST support the drug's mechanism of action?
A researcher is investigating a new drug with potential alpha-1 adrenergic antagonist activity. Which of the following effects would BEST support the drug's mechanism of action?
A patient with pheochromocytoma is scheduled for surgical removal of the tumor. Which of the following adrenergic antagonists is typically used preoperatively to manage hypertension and prevent intraoperative hypertensive crisis?
A patient with pheochromocytoma is scheduled for surgical removal of the tumor. Which of the following adrenergic antagonists is typically used preoperatively to manage hypertension and prevent intraoperative hypertensive crisis?
A patient is prescribed carvedilol for heart failure. What is the MOST important mechanism by which carvedilol provides cardioprotection in this condition?
A patient is prescribed carvedilol for heart failure. What is the MOST important mechanism by which carvedilol provides cardioprotection in this condition?
A patient with hypertension and anxiety is prescribed propranolol. What is MOST likely the rationale for choosing this particular beta-blocker?
A patient with hypertension and anxiety is prescribed propranolol. What is MOST likely the rationale for choosing this particular beta-blocker?
A patient is prescribed an adrenergic antagonist. To effectively predict the net effect of the drug, which of the following steps should be considered FIRST?
A patient is prescribed an adrenergic antagonist. To effectively predict the net effect of the drug, which of the following steps should be considered FIRST?
A patient presents with extravasation of norepinephrine (NE) following IV administration. To counteract the local vasoconstriction and prevent tissue damage, which of the following medications would be MOST appropriate?
A patient presents with extravasation of norepinephrine (NE) following IV administration. To counteract the local vasoconstriction and prevent tissue damage, which of the following medications would be MOST appropriate?
A patient is taking yohimbine as a dietary supplement. What is the expected effect of this supplement on the cardiovascular system?
A patient is taking yohimbine as a dietary supplement. What is the expected effect of this supplement on the cardiovascular system?
A patient with a history of asthma requires a beta-blocker for hypertension management. Which of the following beta-blockers would be the SAFEST choice for this patient?
A patient with a history of asthma requires a beta-blocker for hypertension management. Which of the following beta-blockers would be the SAFEST choice for this patient?
A patient with hypertension is started on nebivolol. Which additional mechanism of action contributes to its antihypertensive effect, beyond beta-1 receptor blockade?
A patient with hypertension is started on nebivolol. Which additional mechanism of action contributes to its antihypertensive effect, beyond beta-1 receptor blockade?
A 60-year-old male patient is prescribed tamsulosin for BPH. He also has a history of orthostatic hypotension. What is the MOST important counseling point to emphasize to this patient?
A 60-year-old male patient is prescribed tamsulosin for BPH. He also has a history of orthostatic hypotension. What is the MOST important counseling point to emphasize to this patient?
A researcher is comparing the effects of carvedilol and labetalol. What is a key difference between these two drugs?
A researcher is comparing the effects of carvedilol and labetalol. What is a key difference between these two drugs?
A patient is prescribed propranolol for essential tremor. What mechanism underlies its effectiveness in treating this condition?
A patient is prescribed propranolol for essential tremor. What mechanism underlies its effectiveness in treating this condition?
A patient experiences a hypertensive crisis during surgical removal of a pheochromocytoma. Why is phenoxybenzamine useful in this scenario?
A patient experiences a hypertensive crisis during surgical removal of a pheochromocytoma. Why is phenoxybenzamine useful in this scenario?
Which drug would typically be used to manage post-traumatic stress disorder-related nightmares?
Which drug would typically be used to manage post-traumatic stress disorder-related nightmares?
A patient is prescribed Alfuzosin. What is Alfuzosin used for?
A patient is prescribed Alfuzosin. What is Alfuzosin used for?
What name ending helps recognize beta blockers?
What name ending helps recognize beta blockers?
Following the administration of an excessive dose of beta- adrenergic-agonist, which of the following symptoms is least likely to be observed?
Following the administration of an excessive dose of beta- adrenergic-agonist, which of the following symptoms is least likely to be observed?
In the image shown, 'Nebivolol' is blocking what channel?
In the image shown, 'Nebivolol' is blocking what channel?
Flashcards
Adrenergic Antagonists
Adrenergic Antagonists
Drugs that generally decrease sympathetic activity, turning down fight or flight responses.
Antagonist
Antagonist
Blocks or opposes the effects of an agonist.
Pheochromocytoma (PCC)
Pheochromocytoma (PCC)
Tumor derived from chromaffin cells of the adrenal gland, often causing excessive sympathetic stimulation.
Phenoxybenzamine
Phenoxybenzamine
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Phentolamine
Phentolamine
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Prazosin
Prazosin
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Tamsulosin
Tamsulosin
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Yohimbine
Yohimbine
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Propranolol
Propranolol
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Timolol
Timolol
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Metoprolol
Metoprolol
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Nebivolol
Nebivolol
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Labetalol
Labetalol
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Carvedilol
Carvedilol
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Study Notes
Adrenergic Antagonists Overview
- Adrenergic antagonists generally decrease sympathetic activity.
- "Sympatholytic" refers to drugs that reduce sympathetic activity.
- Prototype adrenergic antagonists should be listed along with the receptor selectivity
- Receptor binding profiles of prototype adrenergic antagonists should be explained, including their clinical utility and adverse effects
Drug Classes
- Alpha Receptor Antagonists, Beta Receptor Antagonists and Mixed Alpha + Beta Antagonists are categories of drugs to be aware of
- Alpha 1 selective drugs include Prazosin and tamsulosin
- Alpha 2 selective drugs include Yohimbine
- Nonselective alpha drugs include Phentolamine and phenoxybenzamine
- Nonselective beta drugs include Propranolol and Timolol
- Beta 1 selective drugs includes Metoprolol, nebivolol
- Mixed Alpha + Beta Antagonists includes Labetalol and carvedilol
- Beta blockers often have names ending in "LOL"
Receptor Antagonists & Selectivity
- Drugs directly block receptors.
- Affinity levels for receptor targets vary.
- Some drugs are selective, some are not.
- An antagonist blocks or opposes the effects of an agonist.
- Predicting the effects of antagonists involves understanding receptor activation effects by NE, EPI, or DA adrenergic agonists.
Adrenergic Antagonists Effects
- Alpha 1 (Gq) antagonists oppose these effects: constriction of vascular smooth and radial muscle, contraction of bladder sphincter & prostate, ejaculation from seminal vesicles, and increased heart force
- Alpha 2 (Gi) antagonists oppose these effects: NE release inhibition, CNS outflow, vasoconstriction in skin, fluid production in the eye, decreased GI secretions, and decreased tone/motility
- Beta 1 (Gs) antagonists oppose these effects: increased heart rate and force, and renin release from the kidneys
- Beta 2 (Gs) antagonists oppose these effects: bronchodilation of airway smooth muscle, dilation of skeletal muscle vasculature, immune cell response decrease, relaxation of the pregnant uterus, glycogenolysis/gluconeogenesis in the liver, and insulin release from the pancreas
- Beta 3 (Gs) antagonists oppose these effects: relaxation of the bladder detrusor and lipolysis in adipose tissue
Organizing the drugs
- Beta blockers were originally nonselective
- Second-generation drugs were developed for Beta 1 specificity
- Third-generation drugs produced additional helpful therapeutic effects
Alpha Blockers and Pheochromocytoma (PCC)
- Pheochromocytoma is a rare, catecholamine-secreting tumor derived from chromaffin cells of the adrenal gland.
- The tumor is benign, but symptoms result from excessive sympathetic stimulation.
- Treatment for PCC is usually surgical but handling the patients tumor can release NE and EPI into the patient
- More common symptoms of PCC include Hypertension, Sweating, Headache, Anxiety/panic in 30% of patients
- Less common symptoms of PCC include Abdominal pain/nausea/vomiting/diarrhea, Pallor, Hallucinations, Agitation/apprehension, and Tremor
Nonselective Alpha Antagonists
- Phenoxybenzamine:
- It opposes alpha 1/2 vasoconstriction in patients undergoing surgery for PCC to prevent hypertensive crisis.
- It forms a covalent bond with adrenergic receptors, making it a noncompetitive antagonist.
- It cannot get back up to Emax, even with loads of agonist
- It historically treated benign prostatic hyperplasia (BPH) and has investigational use as a male contraceptive by opposing alpha 1 stimulation of ejaculation.
- Phentolamine:
- It opposes alpha 1/2 vasoconstriction to prevent hypertensive crisis in PCC surgery by acting as a competitive antagonist.
- It quickly reverses local vasoconstriction from extravasation DA or NE to prevent tissue blistering and ulceration.
- It increases the absorption of local anesthetics to end their effects.
Alpha 1 Selective Antagonists
- Prazosin:
- Prazosin is used as a treatment for BPH.
- Also, used as a treatment for hypertension.
- It manages Raynaud's syndrome by opening vessels to restore blood flow.
- Useful to treats post-traumatic stress disorder (PTSD)
- Tamsulosin:
- It opposes a1A contraction of prostate smooth muscles and increases urine flow in benign prostatic hyperplasia (enlarged prostate).
- The drug has minimal adverse effects, due to localized expression of a1A receptors and high a1A selectivity.
- Common side effects include dizziness, runny nose, and impaired ejaculation.
Alpha 2 Selective Antagonists
- Yohimbine:
- It opposes a2 presynaptic autoreceptor-mediated decrease in SNS outflow, increasing NE release.
- Derived from the bark of an African tree.
- Marketed as a dietary supplement for treating erectile dysfunction, though there is no published research to support its effectiveness.
Nonselective Beta Blockers
- Propranolol (1st Gen):
- It treats hypertension and tachyarrhythmias by opposing beta 1 increase in heart rate/force and beta 1 renin release
- It is a Class II antiarrhythmic drug.
- It offers short-term treatment of physical signs of anxiety, such as tachycardia, sweating, and flushing.
- Other uses include migraine prophylaxis, restless leg syndrome, and essential tremor, but its mechanisms are still unclear.
- ALL BETA BLOCKERS can mask symptoms of hypoglycemia and are contraindicated in bradycardia.
- Contraindicated in asthma and COPD as it is a nonselective beta antagonist that blocks beta 2 receptors, which causes bronchoconstriction.
- Timolol (1st Gen):
- Opposes Beta 2 stimulation of aqueous humor production in the eye and is used as a treatment of glaucoma and increased intraocular pressure.
- Migraine prophylaxis is also another possible use
Beta 1 Blockers
- Metoprolol (2nd Gen):
- Treats hypertension by opposing Beta 1 increase in heart rate and force and also beta 1 renin release
- Treats symptoms and reduces mortality in angina and after a myocardial infarction
- Safer for use than nonselective in patients who have asthma
- Nebivolol (3rd Gen):
- Same effects as second generation beta blockers, while also treating hypertension
- It has an additional mechanism of action that promotes vasodilation by increasing the release of nitric oxide (NO) from vascular endothelial cells, treating hypertension
Alpha + Beta Blockers
- Labetalol (3rd Gen):
- It has four stereoisomers; two inactive, one is a potent alpha 1 blocker, and another blocks alpha 1, beta 1, and beta 2 receptors.
- Metabolism of each isomer varies between patients, so its alpha vs. beta effects differ.
- The drug opposes alpha 1 vasoconstriction (lowers resistance).
- Also, opposes beta 1 increase in heart rate, force, and renin release.
- IV formulations are available for hypertensive emergencies and treating pregnant patients with hypertension.
- Carvedilol (3rd Gen):
- Like labetalol, it blocks alpha 1, beta 1, and beta 2 receptors.
- It opposes alpha 1 vasoconstriction to lower vascular resistance.
- It opposes beta 1 increases in heart rate and force and renin release.
- It provides beta-arrestin-mediated effects at beta 1 receptors that protect cardiomyocytes against cell death.
- It is used for treatment of hypertension and cardioprotection in patients with congestive heart failure.
Adrenergic antagonists in action
- To apply adrenergic antagonists effectively: think about the receptor(s) an antagonist acts at, recall what happens when an agonist (endogenous ligand or drug) stimulates those receptor(s), and When both an agonist and antagonist are present the overall effect is agonist's effects, minus effects blocked by antagonist.
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Description
Overview of adrenergic antagonists and their effects on sympathetic activity. Covers alpha, beta, and mixed antagonists, including drug classes, receptor selectivity, clinical utility, and adverse effects. Includes Prazosin, Tamsulosin, Yohimbine, Phentolamine and more.
