ABA ABA Pharmacology & Drug Management 2 — Questions and Answers
Question 1: Which local anesthetic has the highest risk of cardiovascular toxicity upon accidental intravascular injection?
- Lidocaine
- Bupivacaine (Correct answer)
- Ropivacaine
- Mepivacaine
Correct answer: Bupivacaine
Bupivacaine binds cardiac sodium channels with high affinity and slow dissociation, making resuscitation from its cardiovascular toxicity extremely difficult.
Question 2: A patient receiving a propofol infusion at 75 mcg/kg/min for 72 hours develops metabolic acidosis, rhabdomyolysis, and cardiac failure. This is MOST consistent with:
- Neuroleptic malignant syndrome
- Propofol infusion syndrome (Correct answer)
- Malignant hyperthermia
- Serotonin syndrome
Correct answer: Propofol infusion syndrome
Propofol infusion syndrome occurs with prolonged high-dose infusions and presents with metabolic acidosis, rhabdomyolysis, renal failure, and cardiac dysfunction.
Question 3: Ketamine's analgesic and dissociative effects are primarily mediated through which receptor?
- GABA-A receptor agonism
- NMDA receptor antagonism (Correct answer)
- Mu-opioid receptor agonism
- Alpha-2 adrenergic receptor agonism
Correct answer: NMDA receptor antagonism
Ketamine is a non-competitive NMDA receptor antagonist, blocking glutamate-mediated excitation to produce dissociative anesthesia and analgesia.
Question 4: Which vasopressor has the MOST selective alpha-1 adrenergic activity with minimal beta effects, making it the preferred agent for spinal hypotension?
- Epinephrine
- Phenylephrine (Correct answer)
- Norepinephrine
- Dopamine
Correct answer: Phenylephrine
Phenylephrine is a pure alpha-1 agonist that increases SVR and corrects spinal hypotension without increasing heart rate, preferred in obstetric anesthesia.
Question 5: The Bier block (IV regional anesthesia) uses which local anesthetic as the standard agent in the United States?
- Bupivacaine 0.5%
- Lidocaine 0.5% (Correct answer)
- Ropivacaine 0.2%
- Mepivacaine 1.5%
Correct answer: Lidocaine 0.5%
Lidocaine 0.5% is the standard agent for Bier blocks in the US; bupivacaine is CONTRAINDICATED due to fatal cardiac toxicity risk if the tourniquet deflates early.
Question 6: Neostigmine reverses neuromuscular blockade by which mechanism?
- Directly stimulating nicotinic receptors
- Inhibiting acetylcholinesterase, increasing ACh at the neuromuscular junction (Correct answer)
- Displacing nondepolarizing agents from receptors
- Enhancing presynaptic ACh release
Correct answer: Inhibiting acetylcholinesterase, increasing ACh at the neuromuscular junction
Neostigmine inhibits acetylcholinesterase, preventing degradation of acetylcholine and allowing it to compete with nondepolarizing agents at nicotinic receptors.
ABA ABA Pharmacology & Drug Management 2
Which local anesthetic has the highest risk of cardiovascular toxicity upon accidental intravascular injection?