MSN Pharmacology for Advanced Practice 1 — Questions and Answers
Question 1: Which receptor mechanism do beta-1 adrenergic antagonists (beta-blockers) use to reduce heart rate?
- Block muscarinic receptors in the SA node
- Competitively block catecholamine binding at beta-1 adrenergic receptors in the SA node (Correct answer)
- Activate potassium channels to hyperpolarize cardiac cells
- Inhibit phosphodiesterase to reduce cyclic AMP
Correct answer: Competitively block catecholamine binding at beta-1 adrenergic receptors in the SA node
Beta-blockers competitively antagonize norepinephrine and epinephrine at beta-1 receptors in the SA node, reducing rate and force of contraction.
Question 2: A patient prescribed warfarin reports adding cranberry juice to their daily diet. What pharmacokinetic concern should the NP have?
- Cranberry juice induces CYP2C9, reducing warfarin levels
- Cranberry juice inhibits CYP2C9, potentially increasing warfarin levels and bleeding risk (Correct answer)
- Cranberry juice directly binds warfarin, reducing absorption
- No significant interaction exists between cranberry and warfarin
Correct answer: Cranberry juice inhibits CYP2C9, potentially increasing warfarin levels and bleeding risk
Cranberry juice inhibits CYP2C9, the primary enzyme metabolizing warfarin's S-enantiomer, potentially raising warfarin plasma levels and increasing hemorrhagic risk.
Question 3: Which class of antihypertensive is first-line for a patient with hypertension and a new diagnosis of chronic kidney disease with proteinuria?
- Thiazide diuretics
- Dihydropyridine calcium channel blockers
- ACE inhibitors or ARBs (Correct answer)
- Beta-blockers
Correct answer: ACE inhibitors or ARBs
ACE inhibitors and ARBs reduce intraglomerular pressure and proteinuria in CKD, providing renoprotection beyond blood pressure lowering, making them first-line in this population.
Question 4: The narrow therapeutic index of digoxin means that which monitoring parameter is most critical?
- Liver function tests
- Serum digoxin level, renal function, and serum potassium (Correct answer)
- Complete blood count
- Thyroid function tests
Correct answer: Serum digoxin level, renal function, and serum potassium
Digoxin toxicity is closely linked to renal clearance (monitors drug accumulation) and potassium levels (hypokalemia sensitizes the heart to digoxin toxicity).
Question 5: Which pharmacodynamic property describes a drug that binds a receptor and produces a maximal response?
- Partial agonist
- Full agonist (Correct answer)
- Competitive antagonist
- Inverse agonist
Correct answer: Full agonist
A full agonist binds to a receptor and produces the maximum possible response (Emax) that the receptor system can generate.
Question 6: Proton pump inhibitors (PPIs) are prodrugs that require which condition to become active?
- Alkaline pH in the small intestine
- Acidic pH in the parietal cell canaliculus to convert to the active sulfenamide (Correct answer)
- First-pass metabolism in the liver
- Enzymatic conversion by colonic bacteria
Correct answer: Acidic pH in the parietal cell canaliculus to convert to the active sulfenamide
PPIs are acid-labile prodrugs that are absorbed systemically and then converted to active sulfenamide compounds by the acidic environment within parietal cell secretory canaliculi.
MSN Pharmacology for Advanced Practice 1
Which receptor mechanism do beta-1 adrenergic antagonists (beta-blockers) use to reduce heart rate?