Calculation of Drug Dosages 12th Edition
Test Bank – Sheila Ogden & Linda
Fluharty (2025/2026 Latest Update)
A nurse is preparing to administer codeine 20 mg PO every 6 hr PRN
pain. Available is codeine oral solution 10 mg/ 5 mL. How many mL
should the nurse administer per dose?
(Round to the nearest whole number. Use a leading zero if it applies. Do
not use a trailing zero.) - ANSWER -Answer: 10 mL
Follow these steps for the Ratio and Proportion method of calculation:
Step 1: What is the unit of measurement the nurse should calculate? mL
Step 2: What is the dose the nurse should administer? Dose to
administer = Desired 20 mg
Step 3: What is the dose available? Dose available = Have 10 mg
Step 4: Should the nurse convert the units of measurement? No
Step 5: What is the quantity of the dose available? 5 mL
Step 6: Set up an equation and solve for X.
Have/Quantity = Desired/X
10 mg/ 5 mL = 20 mg/ X mL
X mL = 10 mL
pg. 1
,Step 7: Round if necessary.
Step 8: Determine whether the amount to administer makes sense. If
there are 10 mg/5 mL and the prescription reads 20 mg, it makes sense
to administer 10 mL. The nurse should administer codeine oral solution
10 mL PO every 6 hr PRN pain.
A nurse is preparing to administer eszopiclone 2,000 mcg PO to a client.
How many mg should the nurse administer?
(Round to the nearest whole number. Use a leading zero if it applies. Do
not use a trailing zero.) - ANSWER -Answer: 2 mg
Follow these steps for the Ratio and Proportion method of calculation:
Step 1: What is the unit of measurement the nurse should calculate?
mg
Step 2: What is the dose the nurse should administer? Dose to
administer = Desired 2,000 mcg
Step 3: What is the dose available? Dose available = Have 1 mg
Step 4: Should the nurse convert the units of measurement? Yes (mcg
does not equal mg)
1,000 mcg/1 mg = 2,000 mcg/X mg
X mg = 2 mg
Step 5: Round if necessary.
Step 6: Determine whether the amount to administer makes sense. If
the prescription reads 2,000 mcg and 1,000 mcg equals 1 mg, it makes
pg. 2
, sense to administer 2 mg. The nurse should administer eszopiclone 2
mg PO.
A nurse is preparing to administer tobramycin 4 mg/kg/day IM divided
in three equal doses to a patient who weighs 60 kg. Available is
tobramycin 40 mg/mL. How many mL should the nurse administer per
dose?
(Round to the nearest whole number. Use a leading zero if it applies. Do
not use a trailing zero.) - ANSWER -Answer: 2 mL
Follow these steps for the Ratio and Proportion method of calculation:
Step 1: What is the unit of measurement the nurse should calculate?
mg
Step 2: Set up an equation and solve for X.
X = Dose per kg × Client's weight in kg
X mg = 4 mg/kg × 60 kg
X mg = 240 mg
The dose is divided into three equal doses; therefore, divide X by 3.
240 mg = 80 mg3
Step 3: What is the unit of measurement the nurse should calculate? mL
Step 4: What is the dose the nurse should administer? Dose to
administer = Desired 80 mg
Step 5: What is the dose available? Dose available = Have 40 mg
pg. 3
Test Bank – Sheila Ogden & Linda
Fluharty (2025/2026 Latest Update)
A nurse is preparing to administer codeine 20 mg PO every 6 hr PRN
pain. Available is codeine oral solution 10 mg/ 5 mL. How many mL
should the nurse administer per dose?
(Round to the nearest whole number. Use a leading zero if it applies. Do
not use a trailing zero.) - ANSWER -Answer: 10 mL
Follow these steps for the Ratio and Proportion method of calculation:
Step 1: What is the unit of measurement the nurse should calculate? mL
Step 2: What is the dose the nurse should administer? Dose to
administer = Desired 20 mg
Step 3: What is the dose available? Dose available = Have 10 mg
Step 4: Should the nurse convert the units of measurement? No
Step 5: What is the quantity of the dose available? 5 mL
Step 6: Set up an equation and solve for X.
Have/Quantity = Desired/X
10 mg/ 5 mL = 20 mg/ X mL
X mL = 10 mL
pg. 1
,Step 7: Round if necessary.
Step 8: Determine whether the amount to administer makes sense. If
there are 10 mg/5 mL and the prescription reads 20 mg, it makes sense
to administer 10 mL. The nurse should administer codeine oral solution
10 mL PO every 6 hr PRN pain.
A nurse is preparing to administer eszopiclone 2,000 mcg PO to a client.
How many mg should the nurse administer?
(Round to the nearest whole number. Use a leading zero if it applies. Do
not use a trailing zero.) - ANSWER -Answer: 2 mg
Follow these steps for the Ratio and Proportion method of calculation:
Step 1: What is the unit of measurement the nurse should calculate?
mg
Step 2: What is the dose the nurse should administer? Dose to
administer = Desired 2,000 mcg
Step 3: What is the dose available? Dose available = Have 1 mg
Step 4: Should the nurse convert the units of measurement? Yes (mcg
does not equal mg)
1,000 mcg/1 mg = 2,000 mcg/X mg
X mg = 2 mg
Step 5: Round if necessary.
Step 6: Determine whether the amount to administer makes sense. If
the prescription reads 2,000 mcg and 1,000 mcg equals 1 mg, it makes
pg. 2
, sense to administer 2 mg. The nurse should administer eszopiclone 2
mg PO.
A nurse is preparing to administer tobramycin 4 mg/kg/day IM divided
in three equal doses to a patient who weighs 60 kg. Available is
tobramycin 40 mg/mL. How many mL should the nurse administer per
dose?
(Round to the nearest whole number. Use a leading zero if it applies. Do
not use a trailing zero.) - ANSWER -Answer: 2 mL
Follow these steps for the Ratio and Proportion method of calculation:
Step 1: What is the unit of measurement the nurse should calculate?
mg
Step 2: Set up an equation and solve for X.
X = Dose per kg × Client's weight in kg
X mg = 4 mg/kg × 60 kg
X mg = 240 mg
The dose is divided into three equal doses; therefore, divide X by 3.
240 mg = 80 mg3
Step 3: What is the unit of measurement the nurse should calculate? mL
Step 4: What is the dose the nurse should administer? Dose to
administer = Desired 80 mg
Step 5: What is the dose available? Dose available = Have 40 mg
pg. 3
