DOSAGE CALCULATIONS MADE
EASY
SOLVING PROBLEMS USING
DIMENSIONAL ANALYSIS
8TH EDITION
• AUTHOR(S)GLORIA PEARL
CRAIG
TEST BANK
,Question 1
Topic: Basic Arithmetic & Unit Conversions (Easy)
A nurse is preparing to administer 0.25 grams of a medication.
The available medication is labeled 500 mg per tablet. How
many tablets should the nurse administer?
A. 0.5 tablets
B. 1 tablet
C. 2 tablets
D. 4 tablets
Correct Answer: A. 0.5 tablets
Rationale:
Step 1: Convert the ordered dose to the same unit as the
available medication. The order is 0.25 g, and the available
medication is in mg. The conversion factor is 1 g = 1000 mg.
Step 2: Set up the dimensional analysis equation to find the
number of tablets.
Tablets=0.25 g1×1000 mg1 g×1 tablet500 mgTablets=10.25 g
×1 g1000 mg×500 mg1 tablet
Step 3: Cancel out the units (g and mg) and solve.
Tablets=0.25×1000500=250500=0.5 tabletsTablets=5000.25×10
00=500250=0.5 tablets
,Medication Safety Note: Always double-check that the unit of
the medication order matches the unit on the medication label.
A common error is misplacing a decimal point during
conversion, which can lead to a tenfold medication error.
Always verify with a second nurse for high-alert medications.
Question 2
Topic: Oral Dosage Calculations (Easy)
The healthcare provider orders alprazolam 0.5 mg by mouth
twice a day for anxiety. The available medication is alprazolam
0.25 mg tablets. How many tablets will the nurse administer for
each dose?
A. 0.5 tablets
B. 1 tablet
C. 1.5 tablets
D. 2 tablets
Correct Answer: D. 2 tablets
Rationale:
Step 1: Identify the ordered dose (0.5 mg) and the available
dose (0.25 mg/tablet).
Step 2: Use dimensional analysis to determine the number of
tablets per dose.
, Tablets per dose=0.5 mg1×1 tablet0.25 mgTablets per dose=10.
5 mg×0.25 mg1 tablet
Step 3: Cancel the units (mg) and solve.
Tablets per dose=0.50.25=2 tabletsTablets per dose=0.250.5
=2 tablets
Medication Safety Note: Verify the medication calculation with
another nurse if the patient is new to the medication or if you
are unsure. This is also an opportunity to educate the patient
on the purpose and proper administration of the medication.
Question 3
Topic: Liquid Medications (Easy)
A provider orders cephalexin 500 mg by mouth. The pharmacy
provides a bottle labeled "Cephalexin 250 mg/5 mL." How many
mL should the nurse administer?
A. 2.5 mL
B. 5 mL
C. 10 mL
D. 15 mL
Correct Answer: C. 10 mL
EASY
SOLVING PROBLEMS USING
DIMENSIONAL ANALYSIS
8TH EDITION
• AUTHOR(S)GLORIA PEARL
CRAIG
TEST BANK
,Question 1
Topic: Basic Arithmetic & Unit Conversions (Easy)
A nurse is preparing to administer 0.25 grams of a medication.
The available medication is labeled 500 mg per tablet. How
many tablets should the nurse administer?
A. 0.5 tablets
B. 1 tablet
C. 2 tablets
D. 4 tablets
Correct Answer: A. 0.5 tablets
Rationale:
Step 1: Convert the ordered dose to the same unit as the
available medication. The order is 0.25 g, and the available
medication is in mg. The conversion factor is 1 g = 1000 mg.
Step 2: Set up the dimensional analysis equation to find the
number of tablets.
Tablets=0.25 g1×1000 mg1 g×1 tablet500 mgTablets=10.25 g
×1 g1000 mg×500 mg1 tablet
Step 3: Cancel out the units (g and mg) and solve.
Tablets=0.25×1000500=250500=0.5 tabletsTablets=5000.25×10
00=500250=0.5 tablets
,Medication Safety Note: Always double-check that the unit of
the medication order matches the unit on the medication label.
A common error is misplacing a decimal point during
conversion, which can lead to a tenfold medication error.
Always verify with a second nurse for high-alert medications.
Question 2
Topic: Oral Dosage Calculations (Easy)
The healthcare provider orders alprazolam 0.5 mg by mouth
twice a day for anxiety. The available medication is alprazolam
0.25 mg tablets. How many tablets will the nurse administer for
each dose?
A. 0.5 tablets
B. 1 tablet
C. 1.5 tablets
D. 2 tablets
Correct Answer: D. 2 tablets
Rationale:
Step 1: Identify the ordered dose (0.5 mg) and the available
dose (0.25 mg/tablet).
Step 2: Use dimensional analysis to determine the number of
tablets per dose.
, Tablets per dose=0.5 mg1×1 tablet0.25 mgTablets per dose=10.
5 mg×0.25 mg1 tablet
Step 3: Cancel the units (mg) and solve.
Tablets per dose=0.50.25=2 tabletsTablets per dose=0.250.5
=2 tablets
Medication Safety Note: Verify the medication calculation with
another nurse if the patient is new to the medication or if you
are unsure. This is also an opportunity to educate the patient
on the purpose and proper administration of the medication.
Question 3
Topic: Liquid Medications (Easy)
A provider orders cephalexin 500 mg by mouth. The pharmacy
provides a bottle labeled "Cephalexin 250 mg/5 mL." How many
mL should the nurse administer?
A. 2.5 mL
B. 5 mL
C. 10 mL
D. 15 mL
Correct Answer: C. 10 mL
