Autonomic Nervous System Agents Flashcards
7 cards from real Pharmacology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Autonomic Nervous System Agents flashcards as text
A patient on prazosin for hypertension reports dizziness when standing up quickly. What is the mechanism behind this adverse effect?
Answer: Blockade of alpha-1 adrenergic receptors causing venous pooling
Prazosin blocks alpha-1 receptors in peripheral vasculature, reducing vascular tone and causing orthostatic hypotension from venous pooling.
Which cholinomimetic agent is used to reverse non-depolarizing neuromuscular blockade and acts by inhibiting acetylcholinesterase?
Answer: Neostigmine
Neostigmine is a reversible acetylcholinesterase inhibitor used to reverse neuromuscular blockade by increasing ACh at the neuromuscular junction.
A patient with pheochromocytoma is scheduled for surgery. Which drug class should be started FIRST to prevent hypertensive crisis during tumor manipulation?
Answer: Alpha-blockers before beta-blockers
Alpha-blockers (e.g., phenoxybenzamine) must be given before beta-blockers to prevent unopposed alpha-mediated vasoconstriction, which would worsen hypertension.
Dobutamine is preferred over dopamine in cardiogenic shock primarily because it:
Answer: Selectively increases cardiac contractility with less peripheral vasoconstriction
Dobutamine predominantly stimulates beta-1 receptors, increasing contractility and cardiac output without the significant vasoconstriction seen with dopamine.
Which antimuscarinic drug is preferred for treating bradycardia during surgery due to its minimal CNS penetration?
Answer: Glycopyrrolate
Glycopyrrolate is a quaternary ammonium compound that does not cross the blood-brain barrier, making it preferred over atropine when CNS effects are undesirable.
A patient taking a non-selective beta-blocker develops severe bronchospasm. Which adrenergic drug would be MOST appropriate to treat this?
Answer: Epinephrine
Epinephrine activates both alpha and beta receptors; high doses can overcome beta-blocker competition at beta-2 receptors to relieve bronchospasm.
Physostigmine differs from neostigmine in clinical use primarily because physostigmine:
Answer: Crosses the blood-brain barrier and can reverse central anticholinergic syndrome
Physostigmine is a tertiary amine that crosses the blood-brain barrier, allowing it to reverse central anticholinergic toxicity (e.g., from antihistamines or tricyclics).