, Question 1
A patient is prescribed continuous IV heparin at 18 units/kg/hr. The patient
weighs 176 lb and the pharmacy supplies heparin 25,000 units in 250 mL
D5W. What is the infusion rate in mL/hr? (Round to nearest whole number.)
A. 14 mL/hr
B. 16 mL/hr
C. 18 mL/hr
D. 20 mL/hr
Correct Answer: A - 14 mL/hr
RATIONALE
Weight = 176 lb ÷ 2.2 = 80 kg. Dose = 18 units/kg/hr × 80 kg = 1,440
units/hr. Concentration = 25,000 units / 250 mL = 100 units/mL. Rate
= 1,440 ÷ 100 = 14.4 mL/hr -> 14 mL/hr. Distractors reflect common
errors in unit conversion or concentration calculation.
Question 2
Which pharmacokinetic parameter is most directly altered by a drug that
induces CYP3A4, leading to decreased efficacy of a co-administered substrate?
A. Volume of distribution
B. Bioavailability
C. Clearance
D. Protein binding
Correct Answer: C - Clearance
RATIONALE
CYP3A4 induction increases hepatic metabolism, thereby increasing
clearance of substrate drugs and reducing their plasma concentration
and efficacy. Volume of distribution and protein binding are
distribution parameters, while bioavailability reflects absorption and
first-pass metabolism; none are the primary parameter altered by
enzyme induction.
Page 2
, Question 3
A patient receiving digoxin has a serum potassium of 3.1 mEq/L. Which
assessment finding is most concerning for digoxin toxicity?
A. Heart rate 58 bpm
B. Visual disturbances with yellow-green halos
C. Blood pressure 118/72 mm Hg
D. Serum digoxin level 0.8 ng/mL
Correct Answer: B - Visual disturbances with yellow-green halos
RATIONALE
Hypokalemia potentiates digoxin toxicity by increasing binding to
Na+/K+-ATPase. Visual disturbances (yellow-green halos) are classic
signs of digoxin toxicity. A heart rate of 58 bpm may be therapeutic,
blood pressure is normal, and a level of 0.8 ng/mL is within
therapeutic range (0.5-2.0 ng/mL).
Question 4
A medication order reads: 'Lorazepam 0.05 mg/kg IV every 6 hours PRN
anxiety.' The patient weighs 132 lb. The vial contains lorazepam 2 mg/mL.
How many milliliters will the nurse administer per dose? (Round to the nearest
tenth.)
A. 1.5 mL
B. 1.8 mL
C. 2.0 mL
D. 2.2 mL
Correct Answer: A - 1.5 mL
RATIONALE
Weight = 132 lb ÷ 2.2 = 60 kg. Dose = 0.05 mg/kg × 60 kg = 3 mg.
Volume = 3 mg ÷ 2 mg/mL = 1.5 mL. Distractors reflect errors in
weight conversion or concentration calculation.
Page 3
, Question 5
Which statement best explains why a drug with a narrow therapeutic index
requires therapeutic drug monitoring (TDM)?
A. Small changes in plasma concentration can lead to subtherapeutic or
toxic effects.
B. The drug is extensively protein-bound, reducing free drug availability.
C. The drug undergoes zero-order kinetics at all doses.
D. The drug has a large volume of distribution, requiring higher loading
doses.
Correct Answer: A - Small changes in plasma concentration can
lead to subtherapeutic or toxic effects.
RATIONALE
A narrow therapeutic index means the difference between effective
and toxic concentrations is small, so TDM is essential to maintain
levels within a safe range. Protein binding, zero-order kinetics, and
volume of distribution are distinct pharmacokinetic properties that
may influence dosing but are not the primary reason for TDM.
Question 6
A patient is prescribed vancomycin 1 g IV every 12 hours. The pharmacy
recommends infusing over 90 minutes. The bag contains 1 g in 250 mL. What
is the infusion rate in mL/hr? (Round to nearest whole number.)
A. 125 mL/hr
B. 167 mL/hr
C. 200 mL/hr
D. 250 mL/hr
Correct Answer: B - 167 mL/hr
Page 4
A patient is prescribed continuous IV heparin at 18 units/kg/hr. The patient
weighs 176 lb and the pharmacy supplies heparin 25,000 units in 250 mL
D5W. What is the infusion rate in mL/hr? (Round to nearest whole number.)
A. 14 mL/hr
B. 16 mL/hr
C. 18 mL/hr
D. 20 mL/hr
Correct Answer: A - 14 mL/hr
RATIONALE
Weight = 176 lb ÷ 2.2 = 80 kg. Dose = 18 units/kg/hr × 80 kg = 1,440
units/hr. Concentration = 25,000 units / 250 mL = 100 units/mL. Rate
= 1,440 ÷ 100 = 14.4 mL/hr -> 14 mL/hr. Distractors reflect common
errors in unit conversion or concentration calculation.
Question 2
Which pharmacokinetic parameter is most directly altered by a drug that
induces CYP3A4, leading to decreased efficacy of a co-administered substrate?
A. Volume of distribution
B. Bioavailability
C. Clearance
D. Protein binding
Correct Answer: C - Clearance
RATIONALE
CYP3A4 induction increases hepatic metabolism, thereby increasing
clearance of substrate drugs and reducing their plasma concentration
and efficacy. Volume of distribution and protein binding are
distribution parameters, while bioavailability reflects absorption and
first-pass metabolism; none are the primary parameter altered by
enzyme induction.
Page 2
, Question 3
A patient receiving digoxin has a serum potassium of 3.1 mEq/L. Which
assessment finding is most concerning for digoxin toxicity?
A. Heart rate 58 bpm
B. Visual disturbances with yellow-green halos
C. Blood pressure 118/72 mm Hg
D. Serum digoxin level 0.8 ng/mL
Correct Answer: B - Visual disturbances with yellow-green halos
RATIONALE
Hypokalemia potentiates digoxin toxicity by increasing binding to
Na+/K+-ATPase. Visual disturbances (yellow-green halos) are classic
signs of digoxin toxicity. A heart rate of 58 bpm may be therapeutic,
blood pressure is normal, and a level of 0.8 ng/mL is within
therapeutic range (0.5-2.0 ng/mL).
Question 4
A medication order reads: 'Lorazepam 0.05 mg/kg IV every 6 hours PRN
anxiety.' The patient weighs 132 lb. The vial contains lorazepam 2 mg/mL.
How many milliliters will the nurse administer per dose? (Round to the nearest
tenth.)
A. 1.5 mL
B. 1.8 mL
C. 2.0 mL
D. 2.2 mL
Correct Answer: A - 1.5 mL
RATIONALE
Weight = 132 lb ÷ 2.2 = 60 kg. Dose = 0.05 mg/kg × 60 kg = 3 mg.
Volume = 3 mg ÷ 2 mg/mL = 1.5 mL. Distractors reflect errors in
weight conversion or concentration calculation.
Page 3
, Question 5
Which statement best explains why a drug with a narrow therapeutic index
requires therapeutic drug monitoring (TDM)?
A. Small changes in plasma concentration can lead to subtherapeutic or
toxic effects.
B. The drug is extensively protein-bound, reducing free drug availability.
C. The drug undergoes zero-order kinetics at all doses.
D. The drug has a large volume of distribution, requiring higher loading
doses.
Correct Answer: A - Small changes in plasma concentration can
lead to subtherapeutic or toxic effects.
RATIONALE
A narrow therapeutic index means the difference between effective
and toxic concentrations is small, so TDM is essential to maintain
levels within a safe range. Protein binding, zero-order kinetics, and
volume of distribution are distinct pharmacokinetic properties that
may influence dosing but are not the primary reason for TDM.
Question 6
A patient is prescribed vancomycin 1 g IV every 12 hours. The pharmacy
recommends infusing over 90 minutes. The bag contains 1 g in 250 mL. What
is the infusion rate in mL/hr? (Round to nearest whole number.)
A. 125 mL/hr
B. 167 mL/hr
C. 200 mL/hr
D. 250 mL/hr
Correct Answer: B - 167 mL/hr
Page 4
