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
, Chapter 1 —Medication Orders & Tablet
Calculations
1. Stem: A provider orders 0.75 g of medication PO. The
pharmacy supplies 250 mg tablets. How many tablets
should the nurse give?
A. 2 tablets
B. 3 tablets
C. 4 tablets
D. 0.75 tablet
Correct Answer: B
Rationales:
• Correct (B): Convert grams to milligrams: 0.75 g × 1000
mg/g = 750 mg. Number of tablets = 750 mg ÷ 250
mg/tablet = 3 tablets.
• (A) 2 tablets reflects under-calculation (250 mg × 2 = 500
mg; nurse would underdose).
• (C) 4 tablets reflects thinking 250 × 4 = 1000 mg (extra 250
mg; overdosing).
• (D) 0.75 tablet reflects misreading units (confusing grams
with tablet count).
Teaching Point: Always convert to the same unit before dividing
by tablet strength.
, 2. Chapter 1 — Section 1.2: IV Flow Rate Basics
Stem: Infuse 1,200 mL of IV fluid over 8 hours. What pump
rate (mL/hr) should be programmed?
A. 100 mL/hr
B. 125 mL/hr
C. 150 mL/hr
D. 160 mL/hr
Correct Answer: C
Rationales:
• Correct (C): mL/hr = total volume ÷ hours = 1200 mL ÷ 8 hr
= 150 mL/hr.
• (A) 100 mL/hr would deliver 800 mL in 8 hours
(underdose).
• (B) 125 mL/hr would deliver 1000 mL in 8 hours
(underdose).
• (D) 160 mL/hr would deliver 1280 mL (slightly too fast).
Teaching Point: Divide total volume by total infusion time to
find mL/hr.
3. Chapter 1 — Section 1.3: Pediatric Weight-Based Dosing &
Liquid Volumes
Stem: Order: Amoxicillin 25 mg/kg/day PO divided every
12 hours for an 18-kg child. Suspension: 125 mg/5 mL.
, How many mL per dose?
A. 7.5 mL
B. 9 mL
C. 10 mL
D. 4.5 mL
Correct Answer: B
Rationales:
• Correct (B): Daily dose = 25 mg/kg × 18 kg = 450 mg/day.
Dose every 12 hr = 450 ÷ 2 = 225 mg/dose. Volume = (225
mg ÷ 125 mg) × 5 mL = 1.8 × 5 mL = 9 mL.
• (A) 7.5 mL reflects calculation 225 mg ÷ (150 mg/5 mL) or
incorrect unit conversion.
• (C) 10 mL reflects rounding up incorrectly (10 mL would be
250 mg, a small overdose).
• (D) 4.5 mL reflects halving the volume incorrectly.
Teaching Point: Convert to mg/kg/day, split doses, then use
concentration to find mL.
4. Chapter 1 — Section 1.4: Units, Concentration & Infusion
Rates
Stem: Heparin 25,000 units are mixed in 500 mL. The order
is to infuse 1,000 units/hour. What mL/hour should be set
on the pump?
A. 2 mL/hr
Calculating Drug Dosages
A Patient-Safe Approach to
Nursing and Math
3rd Edition
• Author(s)Sandra Luz
Martinez de Castillo;
Maryanne Werner-
McCullough
, Chapter 1 —Medication Orders & Tablet
Calculations
1. Stem: A provider orders 0.75 g of medication PO. The
pharmacy supplies 250 mg tablets. How many tablets
should the nurse give?
A. 2 tablets
B. 3 tablets
C. 4 tablets
D. 0.75 tablet
Correct Answer: B
Rationales:
• Correct (B): Convert grams to milligrams: 0.75 g × 1000
mg/g = 750 mg. Number of tablets = 750 mg ÷ 250
mg/tablet = 3 tablets.
• (A) 2 tablets reflects under-calculation (250 mg × 2 = 500
mg; nurse would underdose).
• (C) 4 tablets reflects thinking 250 × 4 = 1000 mg (extra 250
mg; overdosing).
• (D) 0.75 tablet reflects misreading units (confusing grams
with tablet count).
Teaching Point: Always convert to the same unit before dividing
by tablet strength.
, 2. Chapter 1 — Section 1.2: IV Flow Rate Basics
Stem: Infuse 1,200 mL of IV fluid over 8 hours. What pump
rate (mL/hr) should be programmed?
A. 100 mL/hr
B. 125 mL/hr
C. 150 mL/hr
D. 160 mL/hr
Correct Answer: C
Rationales:
• Correct (C): mL/hr = total volume ÷ hours = 1200 mL ÷ 8 hr
= 150 mL/hr.
• (A) 100 mL/hr would deliver 800 mL in 8 hours
(underdose).
• (B) 125 mL/hr would deliver 1000 mL in 8 hours
(underdose).
• (D) 160 mL/hr would deliver 1280 mL (slightly too fast).
Teaching Point: Divide total volume by total infusion time to
find mL/hr.
3. Chapter 1 — Section 1.3: Pediatric Weight-Based Dosing &
Liquid Volumes
Stem: Order: Amoxicillin 25 mg/kg/day PO divided every
12 hours for an 18-kg child. Suspension: 125 mg/5 mL.
, How many mL per dose?
A. 7.5 mL
B. 9 mL
C. 10 mL
D. 4.5 mL
Correct Answer: B
Rationales:
• Correct (B): Daily dose = 25 mg/kg × 18 kg = 450 mg/day.
Dose every 12 hr = 450 ÷ 2 = 225 mg/dose. Volume = (225
mg ÷ 125 mg) × 5 mL = 1.8 × 5 mL = 9 mL.
• (A) 7.5 mL reflects calculation 225 mg ÷ (150 mg/5 mL) or
incorrect unit conversion.
• (C) 10 mL reflects rounding up incorrectly (10 mL would be
250 mg, a small overdose).
• (D) 4.5 mL reflects halving the volume incorrectly.
Teaching Point: Convert to mg/kg/day, split doses, then use
concentration to find mL.
4. Chapter 1 — Section 1.4: Units, Concentration & Infusion
Rates
Stem: Heparin 25,000 units are mixed in 500 mL. The order
is to infuse 1,000 units/hour. What mL/hour should be set
on the pump?
A. 2 mL/hr
