PTCB Pharmacology #4 2 — Questions and Answers
Question 1: Which of the following drugs is a direct thrombin inhibitor?
- Apixaban
- Clopidogrel
- Dabigatran (Correct answer)
- Fondaparinux
Correct answer: Dabigatran
Dabigatran (Pradaxa) is a direct thrombin (Factor IIa) inhibitor. Apixaban and rivaroxaban are Factor Xa inhibitors. Fondaparinux is an indirect Factor Xa inhibitor.
Question 2: What is the antidote for acetaminophen overdose?
- Flumazenil
- Naloxone
- N-acetylcysteine (Correct answer)
- Protamine sulfate
Correct answer: N-acetylcysteine
N-acetylcysteine (Mucomyst, Acetadote) is the antidote for acetaminophen overdose. It replenishes glutathione stores, preventing hepatotoxicity from the reactive metabolite NAPQI.
Question 3: Which drug class do "-floxacin" suffix drugs belong to?
- Cephalosporins
- Aminoglycosides
- Macrolides
- Fluoroquinolones (Correct answer)
Correct answer: Fluoroquinolones
Fluoroquinolones end in "-floxacin" (ciprofloxacin, levofloxacin, moxifloxacin). They inhibit DNA gyrase and are used for respiratory, urinary tract, and skin infections.
Question 4: Diphenhydramine (Benadryl) is associated with which class of adverse effects in elderly patients?
- Nephrotoxicity
- Hepatotoxicity
- Anticholinergic effects (confusion, urinary retention, constipation) (Correct answer)
- Ototoxicity
Correct answer: Anticholinergic effects (confusion, urinary retention, constipation)
First-generation antihistamines like diphenhydramine have strong anticholinergic properties. In elderly patients, this can cause confusion, delirium, urinary retention, constipation, and falls. It is on the Beers Criteria list of drugs to avoid in older adults.
Question 5: Which of the following is the correct mechanism of metformin?
- Stimulates insulin secretion from pancreatic beta cells
- Inhibits glucose absorption in the intestine
- Activates AMPK, reducing hepatic glucose production and improving insulin sensitivity (Correct answer)
- Increases urinary glucose excretion
Correct answer: Activates AMPK, reducing hepatic glucose production and improving insulin sensitivity
Metformin activates AMP-activated protein kinase (AMPK), which reduces hepatic gluconeogenesis, improves peripheral insulin sensitivity, and reduces intestinal glucose absorption. It does NOT cause hypoglycemia alone.
Question 6: Which of the following is a side effect unique to ARBs but NOT ACE inhibitors?
- Hyperkalemia
- Hypotension
- Dry cough is absent (ARBs do not cause cough) (Correct answer)
- Renal impairment
Correct answer: Dry cough is absent (ARBs do not cause cough)
ACE inhibitors cause dry cough in 10–20% of patients (due to bradykinin accumulation). ARBs block angiotensin II receptors directly without affecting bradykinin, so they do NOT cause cough — making them a suitable alternative for ACE inhibitor-intolerant patients.
PTCB Pharmacology #4 2
Which of the following drugs is a direct thrombin inhibitor?