DOSAGE CALCULATIONS MADE
EASY
SOLVING PROBLEMS USING
DIMENSIONAL ANALYSIS
8TH EDITION
• AUTHOR(S)GLORIA PEARL
CRAIG
TEST BANK
,Question 1
A primary care provider prescribes cephalexin 500 mg PO every
6 hours for an adult patient with a urinary tract infection. The
pharmacy dispenses cephalexin capsules labeled 250 mg. How
many capsules should the nurse administer per dose? A. 0.5
capsules B. 1 capsule C. 2 capsules D. 4 capsules
Correct Answer: C
Rationale:
• Step 1: Identify the ordered dose (500 mg) and the
available concentration (250 mg/capsule). The goal is to
find the number of capsules per dose.
• Step 2: Set up the equation using dimensional analysis to
cancel out milligrams (mg) and leave capsules.
capsules/dose=1 dose500 mg×250 mg1 capsule
• Step 3: Calculate the final value.
250500×1=2 capsules/dose
Medication Safety Note: Capsules cannot be split or divided.
Always verify that the calculated number of capsules is a whole
number. If a calculation results in a partial capsule, stop and
clarify the order with the provider or pharmacist.
Question 2
,The healthcare provider orders furosemide 30 mg IV push stat
for a patient presenting with acute pulmonary edema. The vial
on hand is labeled furosemide 40 mg/4 mL. How many
milliliters should the nurse draw up to administer the correct
dose? A. 0.75 mL B. 3 mL C. 4 mL D. 7.5 mL
Correct Answer: B
Rationale:
• Step 1: Identify the ordered dose (30 mg) and the available
concentration (40 mg/4 mL). The goal is to calculate the
volume in milliliters (mL).
• Step 2: Set up the equation using dimensional analysis to
cancel out milligrams (mg) and solve for milliliters (mL).
mL=30 mg×40 mg4 mL
• Step 3: Calculate the final value.
4030×4=40120=3 mL
Medication Safety Note: High-alert medications like
intravenous loop diuretics require precise measurement. Ensure
the volume is drawn up using a syringe appropriate for the
volume (e.g., a 3 mL or 5 mL syringe) to maximize measurement
accuracy.
Question 3
, A patient is prescribed 0.125 mg of oral digoxin daily. The
pharmacy provides digoxin tablets labeled 250 mcg per tablet.
How many tablets should the nurse administer? A. 0.5 tablets B.
1 tablet C. 1.5 tablets D. 2 tablets
Correct Answer: A
Rationale:
• Step 1: Identify the ordered dose (0.125 mg) and the
available dose (250 mcg/tablet). Conversion between
milligrams (mg) and micrograms (mcg) is required
(1 mg=1,000 mcg).
• Step 2: Set up the dimensional analysis to convert units
and solve for the number of tablets.
tablets=0.125 mg×1 mg1,000 mcg×250 mcg1 tablet
• Step 3: Calculate the final value.
0.125×1,000=125 mcg
250125=0.5 tablets
Medication Safety Note: Digoxin is a high-alert medication with
a narrow therapeutic index. Misinterpreting decimal points or
failing to convert units properly can lead to severe toxicity or
underdosing. Always check the metric units carefully.
Question 4
EASY
SOLVING PROBLEMS USING
DIMENSIONAL ANALYSIS
8TH EDITION
• AUTHOR(S)GLORIA PEARL
CRAIG
TEST BANK
,Question 1
A primary care provider prescribes cephalexin 500 mg PO every
6 hours for an adult patient with a urinary tract infection. The
pharmacy dispenses cephalexin capsules labeled 250 mg. How
many capsules should the nurse administer per dose? A. 0.5
capsules B. 1 capsule C. 2 capsules D. 4 capsules
Correct Answer: C
Rationale:
• Step 1: Identify the ordered dose (500 mg) and the
available concentration (250 mg/capsule). The goal is to
find the number of capsules per dose.
• Step 2: Set up the equation using dimensional analysis to
cancel out milligrams (mg) and leave capsules.
capsules/dose=1 dose500 mg×250 mg1 capsule
• Step 3: Calculate the final value.
250500×1=2 capsules/dose
Medication Safety Note: Capsules cannot be split or divided.
Always verify that the calculated number of capsules is a whole
number. If a calculation results in a partial capsule, stop and
clarify the order with the provider or pharmacist.
Question 2
,The healthcare provider orders furosemide 30 mg IV push stat
for a patient presenting with acute pulmonary edema. The vial
on hand is labeled furosemide 40 mg/4 mL. How many
milliliters should the nurse draw up to administer the correct
dose? A. 0.75 mL B. 3 mL C. 4 mL D. 7.5 mL
Correct Answer: B
Rationale:
• Step 1: Identify the ordered dose (30 mg) and the available
concentration (40 mg/4 mL). The goal is to calculate the
volume in milliliters (mL).
• Step 2: Set up the equation using dimensional analysis to
cancel out milligrams (mg) and solve for milliliters (mL).
mL=30 mg×40 mg4 mL
• Step 3: Calculate the final value.
4030×4=40120=3 mL
Medication Safety Note: High-alert medications like
intravenous loop diuretics require precise measurement. Ensure
the volume is drawn up using a syringe appropriate for the
volume (e.g., a 3 mL or 5 mL syringe) to maximize measurement
accuracy.
Question 3
, A patient is prescribed 0.125 mg of oral digoxin daily. The
pharmacy provides digoxin tablets labeled 250 mcg per tablet.
How many tablets should the nurse administer? A. 0.5 tablets B.
1 tablet C. 1.5 tablets D. 2 tablets
Correct Answer: A
Rationale:
• Step 1: Identify the ordered dose (0.125 mg) and the
available dose (250 mcg/tablet). Conversion between
milligrams (mg) and micrograms (mcg) is required
(1 mg=1,000 mcg).
• Step 2: Set up the dimensional analysis to convert units
and solve for the number of tablets.
tablets=0.125 mg×1 mg1,000 mcg×250 mcg1 tablet
• Step 3: Calculate the final value.
0.125×1,000=125 mcg
250125=0.5 tablets
Medication Safety Note: Digoxin is a high-alert medication with
a narrow therapeutic index. Misinterpreting decimal points or
failing to convert units properly can lead to severe toxicity or
underdosing. Always check the metric units carefully.
Question 4
