II Review Q&A | Nightingale
1. A patient is prescribed digoxin for heart failure. What is the primary mechanism of
action of digoxin?
A) Increases heart rate
B) Inhibits the sodium-potassium ATPase pump
C) Promotes vasodilation
D) Decreases cardiac contractility
Correct Answer: Inhibits the sodium-potassium ATPase pump
Rationale: Digoxin inhibits the Na⁺/K⁺ ATPase pump, which increases intracellular
sodium and subsequently calcium levels via the sodium-calcium exchanger. The
increased intracellular calcium enhances myocardial contractility (positive inotropy).
This improves cardiac output in heart failure.
2. A nurse is administering a medication with a half-life of 4 hours. If the initial dose
is 400 mg, what is the approximate amount remaining after 8 hours?
A) 100 mg
B) 200 mg
C) 300 mg
D) 400 mg
Correct Answer: 100 mg
Rationale: After 8 hours, which is two half-lives (4 hours each), the drug
concentration decreases by half twice: 400 mg → 200 mg (after 4 hours) → 100 mg
,(after 8 hours). Understanding half-life is essential for determining dosing intervals
and predicting drug accumulation.
3. A patient is taking warfarin. What is the primary therapeutic effect of warfarin?
A) Increases platelet aggregation
B) Inhibits vitamin K-dependent clotting factors
C) Enhances fibrinolysis
D) Decreases prothrombin time
Correct Answer: Inhibits vitamin K-dependent clotting factors
Rationale: Warfarin inhibits the synthesis of vitamin K-dependent clotting factors (II,
VII, IX, X) in the liver, which prolongs the prothrombin time (PT) and international
normalized ratio (INR). This produces an anticoagulant effect.
4. What is the primary route of elimination for most water-soluble drugs?
A) Lungs
B) Kidneys
C) Liver
D) Skin
Correct Answer: Kidneys
Rationale: Water-soluble drugs are primarily excreted unchanged by the kidneys
through glomerular filtration. Lipid-soluble drugs are more likely to be metabolized
by the liver before elimination. Renal function is a critical factor in dosing many
medications.
, 5. A patient starts drinking grapefruit juice while on a CYP3A4 substrate medication.
What is the expected effect?
A) Decreased drug efficacy
B) Increased drug toxicity
C) No interaction
D) Reduced absorption
Correct Answer: Increased drug toxicity
Rationale: Grapefruit juice inhibits the CYP3A4 enzyme in the intestine and liver,
which reduces the metabolism of many drugs (e.g., statins, calcium channel blockers).
This leads to increased serum drug levels and a higher risk of toxicity.
6. What is the therapeutic serum range for lithium?
A) 0.2–0.4 mEq/L
B) 0.6–1.2 mEq/L
C) 1.5–2.0 mEq/L
D) 2.5–3.0 mEq/L
Correct Answer: 0.6–1.2 mEq/L
Rationale: The therapeutic range for lithium in bipolar disorder is 0.6–1.2 mEq/L for
maintenance therapy. Levels above 1.5 mEq/L increase the risk of toxicity, with
symptoms including tremor, confusion, and renal impairment.
7. Vancomycin is administered for MRSA. What is the preferred route for systemic
infection?
A) Oral