CST Surgical Pharmacology 2 — Questions and Answers
Question 1: Which local anesthetic is an ester-type agent commonly used for spinal anesthesia?
- Lidocaine
- Bupivacaine
- Tetracaine (Correct answer)
- Ropivacaine
Correct answer: Tetracaine
Tetracaine is an ester-type local anesthetic frequently used for spinal (intrathecal) anesthesia.
Question 2: What is the primary mechanism of action of heparin in surgical patients?
- Inhibits vitamin K-dependent clotting factors
- Activates antithrombin III to inhibit thrombin (Correct answer)
- Directly dissolves existing clots
- Inhibits platelet aggregation
Correct answer: Activates antithrombin III to inhibit thrombin
Heparin works by activating antithrombin III, which then inhibits thrombin and other clotting factors.
Question 3: Which drug is used to reverse the effects of benzodiazepines administered during surgery?
- Naloxone
- Neostigmine
- Flumazenil (Correct answer)
- Protamine sulfate
Correct answer: Flumazenil
Flumazenil is a benzodiazepine antagonist that competitively reverses sedation and respiratory depression.
Question 4: Epinephrine is often added to local anesthetics for which primary purpose?
- To increase the speed of onset
- To reduce systemic toxicity by causing vasoconstriction (Correct answer)
- To alkalinize the solution for better diffusion
- To extend the duration by increasing blood flow
Correct answer: To reduce systemic toxicity by causing vasoconstriction
Epinephrine causes vasoconstriction at the injection site, slowing absorption and reducing systemic toxicity while prolonging the block.
Question 5: Which antibiotic class is most commonly used for surgical site infection prophylaxis?
- Fluoroquinolones
- Macrolides
- Cephalosporins (Correct answer)
- Aminoglycosides
Correct answer: Cephalosporins
First-generation cephalosporins such as cefazolin are the standard for most surgical prophylaxis due to their gram-positive coverage and safety profile.
Question 6: Succinylcholine causes a prolonged block in patients with pseudocholinesterase deficiency because:
- The drug is excreted more slowly by the kidneys
- The enzyme responsible for its metabolism is absent or abnormal (Correct answer)
- It converts to a non-depolarizing agent in the blood
- Acetylcholine accumulates and competes for the receptor
Correct answer: The enzyme responsible for its metabolism is absent or abnormal
Succinylcholine is normally hydrolyzed by plasma pseudocholinesterase; a deficiency results in prolonged neuromuscular blockade.
Question 7: What is the antidote for heparin overdose in the surgical setting?
- Vitamin K
- Fresh frozen plasma
- Protamine sulfate (Correct answer)
- Tranexamic acid
Correct answer: Protamine sulfate
Protamine sulfate neutralizes heparin by binding to it and forming an inactive complex.
CST Surgical Pharmacology 2
Which local anesthetic is an ester-type agent commonly used for spinal anesthesia?