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, Section 1.1: Medication Safety Principles
Stem: A physician orders acetaminophen 0.5 g PO for a patient.
The medication available is acetaminophen 250 mg tablets.
How many tablets should the nurse administer?
A. 1 tablet
B. 2 tablets
C. 3 tablets
D. 0.5 tablet
Correct Answer: B
Rationales:
, • Correct (B): Convert grams to milligrams: 0.5 g = 0.5 × 1000
= 500 mg. Determine tablets: 500 mg ÷ 250 mg/tablet = 2
tablets.
• A (1 tablet): Reflects mistake of mis-converting 0.5 g as
250 mg (wrong conversion).
• C (3 tablets): Reflects incorrect division (500 ÷ 250 = 2, not
3) — likely arithmetic error.
• D (0.5 tablet): Reflects incorrect move of decimal point
(assuming 0.5 tablet = 125 mg).
Teaching Point: Convert units first; then calculate dose.
2.
Chapter 1, Section 1.1: Medication Safety Principles —
Decimal and Zero Rules
Stem: Which written dosage is unsafe and should be clarified
with the prescriber?
A. 0.5 mg
B. .5 mg
C. 2 mg
D. 0.25 mg
Correct Answer: B
Rationales:
, • Correct (B): Writing “.5 mg” omits a leading zero and can
be misread (e.g., as 5 mg). Always use a leading zero (0.5
mg).
• A (0.5 mg): Safe — includes the leading zero.
• C (2 mg): Safe — no trailing zero and clear value.
• D (0.25 mg): Safe — properly written with leading zero
where needed (no leading zero needed before a decimal
<1 only if written properly; 0.25 would be preferred but
0.25 is standard).
Teaching Point: Always use a leading zero for doses <1 (e.g., 0.5
mg).
3.
Chapter 1, Section 1.2: Weight-Based Dosing & Unit
Conversions
Stem: Order: Drug X 2 mg/kg IV once. Patient weight = 154 lb.
What is the correct single dose in mg? (Round to the nearest
whole mg.)
A. 70 mg
B. 140 mg
C. 308 mg
D. 35 mg
Correct Answer: B
, Rationales:
• Correct (B): Convert pounds to kilograms: 154 lb ÷ 2.2 = 70
kg. Dose = 2 mg/kg × 70 kg = 140 mg.
• A (70 mg): Reflects using 1 mg/kg instead of 2 mg/kg (half
the correct dose).
• C (308 mg): Reflects using 154 lb as kg (no conversion): 2 ×
154 = 308 (wrong unit).
• D (35 mg): Reflects dividing by 4 (calculation error or
misreading dose as 0.5 mg/kg).
Teaching Point: Convert lb → kg before weight-based dosing.
4.
Chapter 1, Section 1.2: Pediatric Dosing & Division of Daily
Dose
Stem: Order: Amoxicillin 50 mg/kg/day PO in three divided
doses (q8h). Child weight = 33 lb. What is the correct dose per
administration (mg)?
A. 125 mg
B. 250 mg
C. 500 mg
D. 375 mg
Correct Answer: B
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, Section 1.1: Medication Safety Principles
Stem: A physician orders acetaminophen 0.5 g PO for a patient.
The medication available is acetaminophen 250 mg tablets.
How many tablets should the nurse administer?
A. 1 tablet
B. 2 tablets
C. 3 tablets
D. 0.5 tablet
Correct Answer: B
Rationales:
, • Correct (B): Convert grams to milligrams: 0.5 g = 0.5 × 1000
= 500 mg. Determine tablets: 500 mg ÷ 250 mg/tablet = 2
tablets.
• A (1 tablet): Reflects mistake of mis-converting 0.5 g as
250 mg (wrong conversion).
• C (3 tablets): Reflects incorrect division (500 ÷ 250 = 2, not
3) — likely arithmetic error.
• D (0.5 tablet): Reflects incorrect move of decimal point
(assuming 0.5 tablet = 125 mg).
Teaching Point: Convert units first; then calculate dose.
2.
Chapter 1, Section 1.1: Medication Safety Principles —
Decimal and Zero Rules
Stem: Which written dosage is unsafe and should be clarified
with the prescriber?
A. 0.5 mg
B. .5 mg
C. 2 mg
D. 0.25 mg
Correct Answer: B
Rationales:
, • Correct (B): Writing “.5 mg” omits a leading zero and can
be misread (e.g., as 5 mg). Always use a leading zero (0.5
mg).
• A (0.5 mg): Safe — includes the leading zero.
• C (2 mg): Safe — no trailing zero and clear value.
• D (0.25 mg): Safe — properly written with leading zero
where needed (no leading zero needed before a decimal
<1 only if written properly; 0.25 would be preferred but
0.25 is standard).
Teaching Point: Always use a leading zero for doses <1 (e.g., 0.5
mg).
3.
Chapter 1, Section 1.2: Weight-Based Dosing & Unit
Conversions
Stem: Order: Drug X 2 mg/kg IV once. Patient weight = 154 lb.
What is the correct single dose in mg? (Round to the nearest
whole mg.)
A. 70 mg
B. 140 mg
C. 308 mg
D. 35 mg
Correct Answer: B
, Rationales:
• Correct (B): Convert pounds to kilograms: 154 lb ÷ 2.2 = 70
kg. Dose = 2 mg/kg × 70 kg = 140 mg.
• A (70 mg): Reflects using 1 mg/kg instead of 2 mg/kg (half
the correct dose).
• C (308 mg): Reflects using 154 lb as kg (no conversion): 2 ×
154 = 308 (wrong unit).
• D (35 mg): Reflects dividing by 4 (calculation error or
misreading dose as 0.5 mg/kg).
Teaching Point: Convert lb → kg before weight-based dosing.
4.
Chapter 1, Section 1.2: Pediatric Dosing & Division of Daily
Dose
Stem: Order: Amoxicillin 50 mg/kg/day PO in three divided
doses (q8h). Child weight = 33 lb. What is the correct dose per
administration (mg)?
A. 125 mg
B. 250 mg
C. 500 mg
D. 375 mg
Correct Answer: B
