Pharmacology Mastery Test Bank: Medications & Dosages
1. A 68-year-old man with chronic atrial fibrillation is started
on warfarin. His INR on day 3 is 1.6 (therapeutic goal 2.0–
3.0). He asks why he has to wait several days for the drug
to work. Which statement by the nurse is most accurate?
A. “Warfarin takes several days because it must deplete
active vitamin K–dependent clotting factors.”
B. “Warfarin works immediately — your low INR means the
dose is too low and should be doubled now.”
C. “Warfarin only affects platelets, which take time to
regenerate.”
D. “Warfarin is inactive until converted by the liver; wait 24
hours for it to start.”
Correct answer: A
Rationale:
• Why correct: Warfarin inhibits the hepatic synthesis of
vitamin K–dependent clotting factors II, VII, IX, and X.
Factors already circulating must decay; factor II
(prothrombin) has a long half-life (~60–72 hours), so
anticoagulant effect is delayed over several days.
• Why distractors wrong: B is incorrect — warfarin does not
produce an immediate anticoagulant effect, so rapid
doubling risks bleeding without benefit; dosing changes
, require INR-guided adjustments. C is incorrect — warfarin
affects clotting factors, not platelet function. D is
misleading — warfarin acts by inhibiting carboxylation in
the liver, not by a one-time liver activation with a 24-hour
delay; the delay is due to factor half-lives.
• Safety/teaching tip: Teach patients that bridging with
heparin/LMWH may be used when immediate
anticoagulation is needed, and always review drug and
dietary interactions that alter INR.
Difficulty: Moderate
Bloom’s taxonomy: Application
NCLEX client need: Physiological Integrity — Pharmacological
and Parenteral Therapies
2. A 55-year-old man with MRSA bacteremia is receiving
vancomycin 1 g IV every 12 hours. Pre-dose trough level is
10 µg/mL (target 15–20 µg/mL for complicated
bacteremia). Which is the best nursing action?
A. Increase the dose per prescriber order to raise the
trough.
B. Obtain an immediate post-infusion (peak) level.
C. Notify the prescriber and recommend adjusting dose or
dosing interval.
D. Stop the vancomycin and switch to linezolid
immediately.
,Correct answer: C
Rationale:
• Why correct: A trough below therapeutic range in serious
MRSA infections suggests subtherapeutic exposure. The
nurse should notify prescriber and recommend dosing
adjustment (increase dose or shorten interval) guided by
pharmacy and levels.
• Why distractors wrong: A is inappropriate without
prescriber order and interpretation from pharmacy; dosing
adjustments require clinical/pharmacokinetic input. B is
not helpful — vancomycin therapeutic monitoring uses
troughs (and AUC-based monitoring), not routine peaks. D
is premature — change of antibiotic requires prescriber
decision and culture/sensitivity review.
• Safety/teaching tip: Ensure trough level was drawn
correctly (within 30 minutes before next dose) and
communicate timing; document infusion time.
Difficulty: Moderate
Bloom’s taxonomy: Application
NCLEX client need: Physiological Integrity — Reduction of Risk
Potential
3. A 47-year-old woman postoperative after abdominal
surgery reports moderate incisional pain (7/10). She
received morphine 4 mg IV 45 minutes ago. Which nursing
, action is most appropriate now?
A. Give another 4 mg morphine IV now because her pain is
still high.
B. Assess respiratory rate, sedation level, and pain before
giving more opioid.
C. Tell the patient the next dose won’t help and suggest
nonpharmacologic methods only.
D. Give naloxone 0.4 mg IV to reverse morphine effects.
Correct answer: B
Rationale:
• Why correct: After opioid administration the nurse must
evaluate analgesic effect and monitor for respiratory
depression and sedation prior to additional dosing.
Assessment guides safe titration.
• Why distractors wrong: A is unsafe without assessment —
repeated dosing risks hypoventilation. C is dismissive —
while nonpharmacologic measures help, analgesic needs
must be evaluated and treated appropriately. D is
inappropriate — naloxone is for opioid toxicity with
compromised ventilation or severe sedation, not for
inadequate analgesia.
• Safety/teaching tip: Use validated sedation scales and
report RR <12 or increasing sedation; titrate opioids
carefully and consider multimodal analgesia.
1. A 68-year-old man with chronic atrial fibrillation is started
on warfarin. His INR on day 3 is 1.6 (therapeutic goal 2.0–
3.0). He asks why he has to wait several days for the drug
to work. Which statement by the nurse is most accurate?
A. “Warfarin takes several days because it must deplete
active vitamin K–dependent clotting factors.”
B. “Warfarin works immediately — your low INR means the
dose is too low and should be doubled now.”
C. “Warfarin only affects platelets, which take time to
regenerate.”
D. “Warfarin is inactive until converted by the liver; wait 24
hours for it to start.”
Correct answer: A
Rationale:
• Why correct: Warfarin inhibits the hepatic synthesis of
vitamin K–dependent clotting factors II, VII, IX, and X.
Factors already circulating must decay; factor II
(prothrombin) has a long half-life (~60–72 hours), so
anticoagulant effect is delayed over several days.
• Why distractors wrong: B is incorrect — warfarin does not
produce an immediate anticoagulant effect, so rapid
doubling risks bleeding without benefit; dosing changes
, require INR-guided adjustments. C is incorrect — warfarin
affects clotting factors, not platelet function. D is
misleading — warfarin acts by inhibiting carboxylation in
the liver, not by a one-time liver activation with a 24-hour
delay; the delay is due to factor half-lives.
• Safety/teaching tip: Teach patients that bridging with
heparin/LMWH may be used when immediate
anticoagulation is needed, and always review drug and
dietary interactions that alter INR.
Difficulty: Moderate
Bloom’s taxonomy: Application
NCLEX client need: Physiological Integrity — Pharmacological
and Parenteral Therapies
2. A 55-year-old man with MRSA bacteremia is receiving
vancomycin 1 g IV every 12 hours. Pre-dose trough level is
10 µg/mL (target 15–20 µg/mL for complicated
bacteremia). Which is the best nursing action?
A. Increase the dose per prescriber order to raise the
trough.
B. Obtain an immediate post-infusion (peak) level.
C. Notify the prescriber and recommend adjusting dose or
dosing interval.
D. Stop the vancomycin and switch to linezolid
immediately.
,Correct answer: C
Rationale:
• Why correct: A trough below therapeutic range in serious
MRSA infections suggests subtherapeutic exposure. The
nurse should notify prescriber and recommend dosing
adjustment (increase dose or shorten interval) guided by
pharmacy and levels.
• Why distractors wrong: A is inappropriate without
prescriber order and interpretation from pharmacy; dosing
adjustments require clinical/pharmacokinetic input. B is
not helpful — vancomycin therapeutic monitoring uses
troughs (and AUC-based monitoring), not routine peaks. D
is premature — change of antibiotic requires prescriber
decision and culture/sensitivity review.
• Safety/teaching tip: Ensure trough level was drawn
correctly (within 30 minutes before next dose) and
communicate timing; document infusion time.
Difficulty: Moderate
Bloom’s taxonomy: Application
NCLEX client need: Physiological Integrity — Reduction of Risk
Potential
3. A 47-year-old woman postoperative after abdominal
surgery reports moderate incisional pain (7/10). She
received morphine 4 mg IV 45 minutes ago. Which nursing
, action is most appropriate now?
A. Give another 4 mg morphine IV now because her pain is
still high.
B. Assess respiratory rate, sedation level, and pain before
giving more opioid.
C. Tell the patient the next dose won’t help and suggest
nonpharmacologic methods only.
D. Give naloxone 0.4 mg IV to reverse morphine effects.
Correct answer: B
Rationale:
• Why correct: After opioid administration the nurse must
evaluate analgesic effect and monitor for respiratory
depression and sedation prior to additional dosing.
Assessment guides safe titration.
• Why distractors wrong: A is unsafe without assessment —
repeated dosing risks hypoventilation. C is dismissive —
while nonpharmacologic measures help, analgesic needs
must be evaluated and treated appropriately. D is
inappropriate — naloxone is for opioid toxicity with
compromised ventilation or severe sedation, not for
inadequate analgesia.
• Safety/teaching tip: Use validated sedation scales and
report RR <12 or increasing sedation; titrate opioids
carefully and consider multimodal analgesia.
