TEST BANK BASED ON:
Calculating Drug Dosages
A Patient-Safe Approach to Nursing and Math
3rd Edition
• Author(s)Sandra Luz Martinez de Castillo;
Maryanne Werner-McCullough
1. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: An order reads 250 mcg of drug X IV. The vial label reads
0.25 mg per vial. How many milligrams (mg) should you
administer?
A. 0.025 mg
B. 0.25 mg
C. 25 mg
D. 0.00025 mg
Correct Answer: B
,Rationale — Correct: 250 micrograms (mcg) → convert to mg: 1
mg = 1000 mcg → 250 mcg ÷ 1000 = 0.25 mg. Principle: convert
to same units before dosing.
Rationale — Incorrects:
A (0.025 mg): decimal moved one place too far left (250 ÷
10,000) — common misplaced-decimal error.
C (25 mg): magnitude error (multiplied by 100 instead of
dividing by 1,000).
D (0.00025 mg): moved decimal three places left too far
(confused mcg→mg by 1,000,000).
Teaching Point: Always convert micrograms to milligrams by
dividing by 1,000.
2. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: A physician orders 5 mg/kg of Drug Y IV once for a 60-kg
adult. What total dose should you prepare?
A. 30 mg
B. 300 mg
C. 3,000 mg
D. 0.3 mg
Correct Answer: B
,Rationale — Correct: Dose = 5 mg/kg × 60 kg = 300 mg. Step:
multiply weight by dose per kg.
Rationale — Incorrects:
A (30 mg): likely used 0.5 mg/kg or moved decimal left (5 × 6
instead of 5 × 60).
C (3,000 mg): decimal moved one place right (×10 error).
D (0.3 mg): magnitude error (divided by 1,000).
Teaching Point: Multiply mg/kg by patient weight in kg to get
total mg.
3. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: Gentamicin ordered 7 mg/kg IV for a child weighing 12.5
kg. What is the correct dose (showing one decimal)?
A. 8.75 mg
B. 87.5 mg
C. 875 mg
D. 80 mg
Correct Answer: B
Rationale — Correct: 7 mg/kg × 12.5 kg = 87.5 mg. (Step: 7 ×
12.5 = 87.5). Principle: weight-based pediatric dosing.
Rationale — Incorrects:
A (8.75 mg): decimal shifted left (÷10 error).
, C (875 mg): decimal shifted right (×10 error).
D (80 mg): rounding down incorrectly (87.5 ≠ 80).
Teaching Point: Calculate precisely then apply local rounding
rules for pediatric doses.
4. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: Order: Normal saline 1,000 mL IV to infuse over 8 hours.
What infusion rate in mL/hour should you program?
A. 12.5 mL/hr
B. 125 mL/hr
C. 1,250 mL/hr
D. 80 mL/hr
Correct Answer: B
Rationale — Correct: Rate = Volume ÷ Time = 1,000 mL ÷ 8 hr =
125 mL/hr.
Rationale — Incorrects:
A (12.5 mL/hr): decimal shifted left (÷10 error).
C (1,250 mL/hr): decimal shifted right (×10).
D (80 mL/hr): calculated 1,000 ÷ 12.5 (incorrect divisor).
Teaching Point: mL/hr = total mL ÷ total hours; check units
carefully.
Calculating Drug Dosages
A Patient-Safe Approach to Nursing and Math
3rd Edition
• Author(s)Sandra Luz Martinez de Castillo;
Maryanne Werner-McCullough
1. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: An order reads 250 mcg of drug X IV. The vial label reads
0.25 mg per vial. How many milligrams (mg) should you
administer?
A. 0.025 mg
B. 0.25 mg
C. 25 mg
D. 0.00025 mg
Correct Answer: B
,Rationale — Correct: 250 micrograms (mcg) → convert to mg: 1
mg = 1000 mcg → 250 mcg ÷ 1000 = 0.25 mg. Principle: convert
to same units before dosing.
Rationale — Incorrects:
A (0.025 mg): decimal moved one place too far left (250 ÷
10,000) — common misplaced-decimal error.
C (25 mg): magnitude error (multiplied by 100 instead of
dividing by 1,000).
D (0.00025 mg): moved decimal three places left too far
(confused mcg→mg by 1,000,000).
Teaching Point: Always convert micrograms to milligrams by
dividing by 1,000.
2. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: A physician orders 5 mg/kg of Drug Y IV once for a 60-kg
adult. What total dose should you prepare?
A. 30 mg
B. 300 mg
C. 3,000 mg
D. 0.3 mg
Correct Answer: B
,Rationale — Correct: Dose = 5 mg/kg × 60 kg = 300 mg. Step:
multiply weight by dose per kg.
Rationale — Incorrects:
A (30 mg): likely used 0.5 mg/kg or moved decimal left (5 × 6
instead of 5 × 60).
C (3,000 mg): decimal moved one place right (×10 error).
D (0.3 mg): magnitude error (divided by 1,000).
Teaching Point: Multiply mg/kg by patient weight in kg to get
total mg.
3. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: Gentamicin ordered 7 mg/kg IV for a child weighing 12.5
kg. What is the correct dose (showing one decimal)?
A. 8.75 mg
B. 87.5 mg
C. 875 mg
D. 80 mg
Correct Answer: B
Rationale — Correct: 7 mg/kg × 12.5 kg = 87.5 mg. (Step: 7 ×
12.5 = 87.5). Principle: weight-based pediatric dosing.
Rationale — Incorrects:
A (8.75 mg): decimal shifted left (÷10 error).
, C (875 mg): decimal shifted right (×10 error).
D (80 mg): rounding down incorrectly (87.5 ≠ 80).
Teaching Point: Calculate precisely then apply local rounding
rules for pediatric doses.
4. Chapter 1 — Section: Principles of Safe Medication
Administration — Title: Safety in Medication
Administration
Stem: Order: Normal saline 1,000 mL IV to infuse over 8 hours.
What infusion rate in mL/hour should you program?
A. 12.5 mL/hr
B. 125 mL/hr
C. 1,250 mL/hr
D. 80 mL/hr
Correct Answer: B
Rationale — Correct: Rate = Volume ÷ Time = 1,000 mL ÷ 8 hr =
125 mL/hr.
Rationale — Incorrects:
A (12.5 mL/hr): decimal shifted left (÷10 error).
C (1,250 mL/hr): decimal shifted right (×10).
D (80 mL/hr): calculated 1,000 ÷ 12.5 (incorrect divisor).
Teaching Point: mL/hr = total mL ÷ total hours; check units
carefully.
