[PCOL] 2.4 Sympathetic Nervous System (Sympatholytics)

The alpha blockers are broadly classified into two groups based on their receptor affinity. What are these two groups?

A. Short-acting and Long-acting

B. Competitive and Non-competitive

C. Non-selective and Selective

D. Central and Peripheral

C. Non-selective and Selective

Explanation: Alpha blockers are classified into non-selective (alpha1=alpha2) and selective (alpha1 or alpha2 specific) agents.

What is the general clinical use for all alpha blockers, due to their ability to treat digital vasospasm caused by cold or stress?

A. Management of Carcinoid's Syndrome

B. Management of Erectile Dysfunction

C. Management of Raynaud's Syndrome

D. Treatment of Sympathomimetics Poisoning

C. Management of Raynaud's Syndrome

Explanation: Alpha blockers are the Drug of Choice (DOC) for the management of Raynaud's Syndrome, a condition involving digital vasospasm, by promoting vasodilation.

Which non-selective alpha blocker is characterized as an irreversible, non-competitive antagonist with a long duration of action?

A. Phentolamine

B. Prazosin

C. Phenoxybenzamine

D. Tamsulosin

C. Phenoxybenzamine

Explanation: Phenoxybenzamine is the irreversible, non-competitive alpha blocker. This strong, long-lasting blockade allows it to be used for presurgical management of pheochromocytoma.

Which non-selective alpha blocker is the Drug of Choice (DOC) in the management of Carcinoid's Syndrome?

A. Phentolamine

B. Phenoxybenzamine

C. Prazosin

D. Doxazosin

B. Phenoxybenzamine

Explanation: Phenoxybenzamine is the DOC for Carcinoid's Syndrome, due to its ability to block not only alpha1 but also 5-HT (serotonin) receptors, which are hypersecreted by the enterochromaffin cell malignancy.

Which drug is used for the management of pheochromocytoma during surgery?

A. Phenoxybenzamine

B. Phentolamine

C. Clonidine

D. Methyldopa

B. Phentolamine

Explanation: Phentolamine (reversible, short-acting, competitive blocker) is used for the management of pheochromocytoma specifically during surgery to control sudden catecholamine release. Phenoxybenzamine is used for pre-surgical management.

Phentolamine is used clinically as an antidote in the treatment of what type of drug toxicity?

A. Cholinergic agents

B. Sympathomimetics poisoning

C. Opioid overdose

D. Beta blocker toxicity

B. Sympathomimetics poisoning

Explanation: Phentolamine is listed as the antidote in the treatment of sympathomimetics poisoning, as it reverses the massive vasoconstriction and hypertension caused by excessive alpha receptor stimulation.

Phentolamine is clinically used for the management of erectile dysfunction via which specific administration route?

A. Oral capsule

B. Intravenous infusion

C. Direct injection to the penile shaft

D. Sublingual tablet

C. Direct injection to the penile shaft

Explanation: Phentolamine is noted to be administered via direct injection to the penile shaft for the management of erectile dysfunction, where its alpha blockade causes vasodilation and aids erection.

Which set of drugs are classified as selective alpha blockers?

A. Phenoxybenzamine and Phentolamine

B. Prazosin, Doxazosin, and Terazosin

C. Ephedrine and Tyramine

D. Isoproterenol and Dobutamine

B. Prazosin, Doxazosin, and Terazosin

Explanation: Prazosin, Doxazosin, and Terazosin are listed as examples of selective alpha blockers. Tamsulosin, Rauwolscine, and Yohimbine are also in this category.

What is the initial treatment required for pheochromocytoma before surgical incision is performed?

A. Beta blockers only

B. Alpha blockers only

C. Initial control with both alpha and beta blockers

D. Angiotensin Converting Enzyme (ACE) inhibitors

C. Initial control with both alpha and beta blockers

Explanation: The treatment section for pheochromocytoma specifies that the initial control involves using both alpha and beta blockers to stabilize the patient before surgery.

What is a common adverse drug reaction (ADR) of alpha antagonists, especially after the first dose, that can be remedied by starting at a low dose and advising bedtime doses?

A. Tachycardia

B. Hypertension exacerbation

C. Orthostatic hypotension leading to syncope (first dose phenomenon)

D. Hemorrhagic stroke

C. Orthostatic hypotension leading to syncope (first dose phenomenon)

Explanation: Orthostatic hypotension (and syncope) is a major ADR for alpha antagonists, known as the "first dose phenomenon." Strategies to manage it include gradual position change, bedtime doses, and low initial doses.

Which group of selective alpha1 blockers is primarily used for the management of hypertension?

A. Alfuzosin and Tamsulosin

B. Yohimbine and Rauwolscine

C. Prazosin, Doxazosin, and Terazosin

D. Silodosin and Phenoxybenzamine

C. Prazosin, Doxazosin, and Terazosin

Explanation: Prazosin, Doxazosin, and Terazosin are listed as the selective alpha1 blockers used specifically for their vasodilator properties in the management of hypertension.

What is the mechanism by which selective alpha1 blockers manage hypertension?

A. Increasing heart rate and contractility (inotropy)

B. Inhibiting catecholamine release from the presynapse

C. Causing vasodilation

D. Blocking calcium channels

C. Causing vasodilation

Explanation: By blocking alpha1 receptors on vascular smooth muscle, these drugs prevent norepinephrine from causing vasoconstriction, leading to vasodilation and reduced blood pressure.

The "First Dose Phenomenon," a significant side effect of selective alpha1 blockers, is characterized by what two main symptoms?

A. Reflex tachycardia and flushing

B. Orthostatic hypotension and syncope

C. Tachyarrhythmia and hypertension

D. Urinary retention and edema

B. Orthostatic hypotension and syncope

Explanation: The First Dose Phenomenon is a sudden drop in blood pressure (orthostatic hypotension) upon standing, often leading to fainting (syncope), and is most common after the initial dose or a large dose increase.

The risk of the First Dose Phenomenon with selective alpha1 blockers is triggered by which of the following conditions?

A. Initial dose, big dose, or use of another anti-hypertensive

B. Taking the dose at bedtime

C. Using a half or quarter of the usual dose

D. Taking the dose with food

A. Initial dose, big dose, or use of another anti-hypertensive

Explanation: The triggers listed for the First Dose Phenomenon are the initial dose, a big dose, or when starting the use of another anti-hypertensive drug alongside the alpha blocker.

What is the remedy recommended to mitigate the risk of the First Dose Phenomenon?

A. Take the first dose at bedtime and start at a low dose (e.g., half or quarter)

B. Take the first dose in the morning and avoid standing quickly

C. Increase the dose rapidly over a few days

D. Co-administer with a beta agonist

A. Take the first dose at bedtime and start at a low dose (e.g., half or quarter)

Explanation: Remedies for the First Dose Phenomenon include giving the first dose at bedtime to minimize effects when standing and starting with a low dose (one-half or one-quarter of the usual dose).

Which selective alpha1 blockers are primarily used to shrink the enlarged prostate gland for the relief of urinary retention in patients with Benign Prostatic Hyperplasia (BPH)?

A. Prazosin and Terazosin

B. Alfuzosin and Tamsulosin

C. Yohimbine and Rauwolscine

D. Phenoxybenzamine and Phentolamine

B. Alfuzosin and Tamsulosin

Explanation: Alfuzosin and Tamsulosin are listed as the selective alpha1 blockers used for BPH, specifically to relax smooth muscle in the prostate and bladder neck to relieve urinary retention. Silodosin is also listed as a third-generation BPH treatment.

Selective alpha2 blockers, such as Yohimbine and Rauwolscine, are generally described as having what type of value?

A. DOC for BPH

B. DOC for erectile dysfunction

C. Significant therapeutic value for hypertension

D. No therapeutic value

D. No therapeutic value

Explanation: The general description for Selective alpha2 blockers states that they have no therapeutic value.

What is the FDA-approved clinical use for the selective alpha2 blocker Yohimbine?

A. CNS stimulant and local anesthetic

B. Management of erectile dysfunction (ED)

C. FDA approved aphrodisiac

D. Treatment of Raynaud's syndrome

C. FDA approved aphrodisiac

Explanation: Yohimbine is described as a CNS stimulant and local anesthetic, and it is FDA approved as an aphrodisiac.

Which third-generation selective alpha1 blocker, along with Silodosin, is noted to be prostate specific for the management of BPH?

A. Alfuzosin

B. Tamsulosin

C. Doxazosin

D. Prazosin

B. Tamsulosin

Explanation: Tamsulosin is explicitly listed as a third-generation, prostate-specific alpha1 antagonist (along with Silodosin), meaning it targets the alpha1A receptor in the prostate more selectively than older agents like Prazosin.

What is Rauwolscine, an example of a selective alpha2 blocker, chemically defined as in relation to Yohimbine?

A. An isomer with less potency

B. A stereoisomer of yohimbine with similar but more potent effects

C. A prodrug of yohimbine

D. A metabolite of yohimbine

B. A stereoisomer of yohimbine with similar but more potent effects

Explanation: Rauwolscine is described as a stereoisomer of yohimbine (isoyohimbine) with similar but more potent effects.

What is the default mechanism of action (MOA) for Beta Blockers, and what are the resulting effects on the heart?

A. alpha1 antagonism; Increased Inotropy, Chronotropy, Dromotropy

B. beta2 antagonism; Bronchodilation

C. beta1 antagonism; Negative Inotropy, Chronotropy, Dromotropy (cardiac depression)

D. D1 agonism; Peripheral vasodilation

C. beta1 antagonism; Negative Inotropy, Chronotropy, Dromotropy (cardiac depression)

Explanation: The default MOA is blocking the beta1 receptor, which reduces sympathetic stimulation, resulting in negative effects on contractility (Inotropy), heart rate (Chronotropy), and conduction velocity (Dromotropy).

Beta blockers are classified as what type of antiarrhythmic agents?

A. Class 1

B. Class 2

C. Class 3

D. Class 4

B. Class 2

Explanation: Beta blockers are antiarrhythmic agents and are formally classified as Class 2 agents (often recalled by the mnemonic PEAce for Propranolol, Esmolol, and Acebutolol).

Beta blockers are used in the management of glaucoma by which mechanism?

A. Decreasing aqueous humor secretion/production

B. Increasing aqueous humor outflow

C. Causing miosis (pupil constriction)

D. Blocking alpha2 receptors

A. Decreasing aqueous humor secretion/production

Explanation: Topical beta blockers like Timolol and Betaxolol work by reducing the production of aqueous humor, thereby lowering intraocular pressure.

Which of the following is a clinical use of Propranolol related to thyroid function?

A. Directly blocking T3 receptors in the heart

B. Inhibiting the peripheral conversion of T4 to T3

C. Increasing the synthesis of thyroid hormones

D. Management of unstable Hyperthyroidism

B. Inhibiting the peripheral conversion of T4 to T3

Explanation: Propranolol is specifically used to manage the sympathetic symptoms of hyperthyroidism and also blocks the peripheral enzymatic conversion of the relatively inactive T4 to the active T3.

Which four specific beta blockers are indicated for the management of stable heart failure (CHF)?

A. Propranolol, Esmolol, Acebutolol, and Labetalol

B. Bisoprolol, Metoprolol, Carvedilol, and Nebivolol

C. Timolol, Betaxolol, and Sotalol

D. Prazosin, Doxazosin, and Terazosin

B. Bisoprolol, Metoprolol, Carvedilol, and Nebivolol

Explanation: The four beta blockers specifically listed for the management of stable heart failure (CHF) are Bisoprolol, Metoprolol, Carvedilol, and Nebivolol.

What is the major concern (side effect) when using non-selective beta blockers like Propranolol in patients with pre-existing lung conditions like asthma or COPD?

A. Hypertension

B. Bronchospasm

C. Hyperuricemia

D. Erectile dysfunction

B. Bronchospasm

Explanation: Non-selective beta blockers block beta2 receptors in the bronchi, which can cause life-threatening bronchospasm in susceptible patients.

Abrupt cessation of beta blocker therapy can lead to what dangerous side effect?

A. Bronchospasm

B. Hypoglycemia masking

C. Rebound Hypertension and tachycardia

D. Heart block

C. Rebound Hypertension and tachycardia

Explanation: The sudden removal of beta antagonism leads to a surge in sympathetic activity, causing Rebound HTN and tachycardia. The remedy is to taper the dose over 10-14 days.

Co-administration of beta blockers is contraindicated with which specific class of calcium channel blockers (CCBs) due to the risk of enhanced negative inotropic and dromotropic effects?

A. Dihydropyridines (DHP) like Nifedipine

B. Non-Dihydropyridines (Non-DHP) like Verapamil and Diltiazem

C. L-type CCBs

D. T-type CCBs

B. Non-Dihydropyridines (Non-DHP) like Verapamil and Diltiazem

Explanation: Both beta blockers and Non-DHP CCBs (Verapamil, Diltiazem) decrease cardiac conduction and contractility. Using them concomitantly can cause an "Extension Effect" leading to severe bradycardia or heart block.

Beta blockers are not contraindicated in patients with Type 2 Diabetes Mellitus (T2DM), but they have a "masking effect" related to which condition?

A. Hyperlipidemia

B. Hyperuricemia

C. Hypoglycemia

D. Erectile dysfunction

C. Hypoglycemia

Explanation: Beta blockers can mask the sympathetic signs (tachycardia, tremors) of hypoglycemia, delaying the patient's recognition of low blood sugar, thus requiring careful monitoring (CBG).

What is the recommended treatment/antidote for severe beta blocker toxicity leading to severe bradycardia and heart block?

A. Epinephrine

B. Norepinephrine

C. Atropine

D. Glucagon

D. Glucagon

Explanation: Glucagon is the antidote for severe beta blocker toxicity because it increases cAMP levels (bypassing the blocked beta receptor) to restore contractility and heart rate.

Besides HTN and Angina, what is another prophylactic use of Propranolol?

A. Prophylaxis of asthma exacerbations

B. Prophylaxis of migraine headache

C. Prophylaxis of Raynaud's Syndrome

D. Prophylaxis of Hyperlipidemia

B. Prophylaxis of migraine headache

Explanation: Propranolol is specifically listed for the prophylaxis of migraine headache, as well as for the treatment of performance anxiety (stage fright).

Which of the following conditions is a contraindication for the use of beta blockers?

A. Chronic Stable Angina Pectoris

B. Hypertension

C. Unstable Heart Failure

D. Stage fright

C. Unstable Heart Failure

Explanation: Beta blockers are contraindicated in patients with unstable or active Heart Failure but are indicated and beneficial for patients with stable Heart Failure (CHF).

I will generate flashcards covering the BETA BLOCKERS based on their classification (Selectivity, ISA, Membrane Stabilizing Effect, and Alpha Blocking Effect), key drugs, characteristics (longest/shortest acting), and specific contraindications/side effects, strictly adhering to all formatting and content constraints.

Which classification of beta blockers is less likely to cause bronchospasm and can be used more safely in patients with asthma?

A. Non-selective (beta1 and beta2 blockade)

B. Cardioselective (beta1 selective)

C. Intrinsic Sympathomimetic Activity (ISA)

D. Alpha-blocking effect

B. Cardioselective (beta1 selective)

Explanation: Cardioselective beta blockers primarily block beta1 receptors, minimizing the antagonism of beta2 receptors in the bronchi, thereby reducing the risk of bronchospasm compared to non-selective agents.

Which drug is considered the prototype for non-selective beta blockers?

A. Metoprolol

B. Propranolol (Inderal)

C. Esmolol

D. Labetalol

B. Propranolol (Inderal)

Explanation: Propranolol is listed as the prototype for the non-selective beta blockers (NSTP).

Which non-selective beta blocker is classified as a Class III Antiarrhythmic agent?

A. Nadolol

B. Propranolol

C. Sotalol

D. Timolol

C. Sotalol

Explanation: Sotalol, besides being a non-selective beta blocker (NSTP), is also specifically classified as a Class III Antiarrhythmic.

Which cardioselective beta blocker has the shortest half-life (t1/2=10 minutes), is administered via IV infusion, and is used for managing perioperative hypertension?

A. Nadolol

B. Metoprolol

C. Esmolol

D. Acebutolol

C. Esmolol

Explanation: Esmolol is characterized as having the shortest half-life, is an ester, and is used intravenously for acute conditions like perioperative hypertension.

What unique characteristic of cardioselective beta blockers makes them the "most cardioselective" agent?

A. Metoprolol

B. Atenolol

C. Nebivolol

D. Bisoprolol

C. Nebivolol

Explanation: Nebivolol is listed as the most cardioselective agent among the selective beta blockers (BBEAMNC).

Beta blockers with Intrinsic Sympathomimetic Activity (ISA) have a partial agonistic effect on which receptor?

A. Alpha1

B. Beta1

C. Beta2

D. D1

C. Beta2

Explanation: ISA is characterized as having a partial beta agonistic effect, which is thought to be a partial beta2 agonistic effect. This partial agonism leads to a better safety profile and less severe rebound hypertension upon withdrawal.

Which group of beta blockers is less likely to cause rebound hypertension when withdrawn abruptly (Cold Turkey)?

A. Non-selective beta blockers

B. Beta blockers with ISA

C. Beta blockers with Membrane Stabilizing Activity (MSA)

D. Beta blockers with Alpha Blocking Effect

B. Beta blockers with ISA

Explanation: ISA agents are less likely to cause rebound hypertension when withdrawn abruptly because the partial agonistic effect tapers more gently than a full antagonistic effect.

What is the mechanism of action associated with beta blockers that have a Membrane Stabilizing Effect (MSA)?

A. Direct stimulation of beta2 receptors

B. Alpha1 receptor blockade

C. Quinidine-like effect or Sodium channel blockade

D. Inhibition of peripheral T4 to T3 conversion

C. Quinidine-like effect or Sodium channel blockade

Explanation: MSA is described as a "quinidine-like effect" or an Na channel blocker (anti-arrhythmic effect), which provides a local anesthetic action.

Which drug is the longest acting beta blocker?

A. Propranolol

B. Esmolol

C. Nadolol

D. Timolol

C. Nadolol

Explanation: Nadolol (NSTP) is specifically noted to be the longest acting beta blocker.

Which two beta blockers possess both beta blockade and alpha blocking effect?

A. Propranolol and Metoprolol

B. Nadolol and Sotalol

C. Carvedilol and Labetalol

D. Timolol and Betaxolol

C. Carvedilol and Labetalol

Explanation: Carvedilol and Labetalol (CLN group) are the mixed action beta blockers that also cause vasodilation due to their alpha blocking effect. Nebivolol is also listed in this group.

What is the specific contraindication for the administration of Nadolol and Sotalol?

A. They cause rebound effects.

B. They do not cross the CNS.

C. They have high ISA.

D. They block Na channels.

B. They do not cross the CNS.

Explanation: Nadolol and Sotalol are specifically noted in the NOTES as drugs that do not cross the CNS.

The beta2-antagonist Butoxamine is described as having what clinical status?

A. DOC for bronchial asthma

B. Used as a local anesthetic

C. Used in research with no clinical use

D. Used in IV infusion for perioperative HTN

C. Used in research with no clinical use

Explanation: Butoxamine, a beta2-antagonist, is explicitly listed as a research drug with no clinical use.