C HAPTER 9: C ALCULATING O RAL
M EDICATION D OSES
Castillo: Calculating Drug Dosages: A Patient -Safe Approach to Nursing
and Math 2nd Edition
MULTIPLE CHOICE
1. The MD order is to administer C efdinir for Oral Suspension 0.375 g PO
BID. A bottle of Cefdinir for Oral Suspension USP 250 mg/5 mL (60 mL
when reconstituted) is available. The label notes:
DIRECTIONS FOR RECONSTITUTION: Prepare suspension by
adding a total of 50 mL water to the bottle . Shake well before each
use. Use within 10 days of reconstitution.
Based on this information, what is the dose will the nurse administer to
the patient?
A. 7.5 m L per dose
B. 10 m L per dose
C. 12.5 mL per dose
D. 15 m L per dose
ANS: A
Feedback
, Choose a method of calculation to solve for x. Note that the units in
the order and the available medication are not the same and need to be
converted (g to mg). After calculating, the nurse will administer 7.5
mL of Cefdinir.
2. A bottle of Azithromycin Oral Suspension USP 10 0 mg/5 mL (15 m L when
reconstituted) is available. The label notes the following:
DIRECTIONS FOR RECONSTITUTION: Prepare suspension by
adding a total of 9 mL water to the bottle. Shake well before each use.
After reconstitution, what is the total amount in the bottle?
A. 5 mL
B. 9 mL
C. 15 m L
D. 20 m L
ANS: C
Feedback
Following the directions for reconstitution, the nurse will mix the
powder with 9 mL water. The bottle will then contain a total amount of
15 m L.
3. The MD order is to administer Ondansetron Oral Soluti on 6 mg PO 30 min
before chemotherapy treatment. The pharmacy provides a bottle of
Ondansetron Oral Solution USP 4 mg/5 mL. What dose will the nurse
instruct the patient to take?
, A. 5 mL
B. 7.5 m L
C. 8 mL
D. 8.5 m L
ANS: B
Feedback
No conversions are needed to solve this problem. Choose a method of
calculation and solve for x. The patient will take 7.5 m L ondansetron
solution.
4. The MD changes the dose of the patient’s diltiazem hydrochloride to:
Diltiazem hydrochloride 180 mg PO every 12 hr.
The nurse is preparing to administer the new order and finds several
tablets labeled diltiazem hydrochloride ER 90 mg in the patient’s drawer.
Which action by the nurse is correct?
A. Call the MD to clarify the ordered dose.
B. Administer two 90 mg ER tablets to the patient.
C. Call the pharmacy to obtain the new dose.
D. Administer one 90 mg ER tablet for the morning dose.
ANS: C
Feedback
The nurse should call the pharmacist to obtain the new dose to
administer to the patient. The order does not need MD clarification.
, The nurse should not administer the 90 mg ER tablets because these are
“extended-release” tablets.
5. MD Order: Caduet (amlodipine 10 mg/atorvastatin 80 mg) 1 tablet PO
dail y. The nurse finds Caduet 10/40 mg tablets in the patient’s medication
drawer. What initial action by the nurse shows that safe medication
administration practice was demonstrated?
A. Using two patient identifiers before administering the ordered dose.
B. Administering two Caduet 10 mg/40 mg tablets to the patient.
C. Requesting the ordered dose from the pharmacy.
D. Splitting the tablet in half.
ANS: C
Feedback
Requesting the ordered dose from the pharmacy demonstrates safe
practice because Caduet 10 mg/80 mg is a fixed dose combination drug
and therefore must be administered as ordered. Using two patient
identifiers demonstrates safe practice and must be done after preparing
the dose and at the bedside before the administration of the medication.
Administering two Caduet 10 mg/40 mg tablets and splitting the tablet
will result in the administration of an incorrect dose.
6. MD Order: Vibram ycin syrup 75 mg PO BID. Pharmacy sends:
Vibram ycin syrup 25 mg/ 5 mL. The nurse measures the dose in the
medicine cup.
M EDICATION D OSES
Castillo: Calculating Drug Dosages: A Patient -Safe Approach to Nursing
and Math 2nd Edition
MULTIPLE CHOICE
1. The MD order is to administer C efdinir for Oral Suspension 0.375 g PO
BID. A bottle of Cefdinir for Oral Suspension USP 250 mg/5 mL (60 mL
when reconstituted) is available. The label notes:
DIRECTIONS FOR RECONSTITUTION: Prepare suspension by
adding a total of 50 mL water to the bottle . Shake well before each
use. Use within 10 days of reconstitution.
Based on this information, what is the dose will the nurse administer to
the patient?
A. 7.5 m L per dose
B. 10 m L per dose
C. 12.5 mL per dose
D. 15 m L per dose
ANS: A
Feedback
, Choose a method of calculation to solve for x. Note that the units in
the order and the available medication are not the same and need to be
converted (g to mg). After calculating, the nurse will administer 7.5
mL of Cefdinir.
2. A bottle of Azithromycin Oral Suspension USP 10 0 mg/5 mL (15 m L when
reconstituted) is available. The label notes the following:
DIRECTIONS FOR RECONSTITUTION: Prepare suspension by
adding a total of 9 mL water to the bottle. Shake well before each use.
After reconstitution, what is the total amount in the bottle?
A. 5 mL
B. 9 mL
C. 15 m L
D. 20 m L
ANS: C
Feedback
Following the directions for reconstitution, the nurse will mix the
powder with 9 mL water. The bottle will then contain a total amount of
15 m L.
3. The MD order is to administer Ondansetron Oral Soluti on 6 mg PO 30 min
before chemotherapy treatment. The pharmacy provides a bottle of
Ondansetron Oral Solution USP 4 mg/5 mL. What dose will the nurse
instruct the patient to take?
, A. 5 mL
B. 7.5 m L
C. 8 mL
D. 8.5 m L
ANS: B
Feedback
No conversions are needed to solve this problem. Choose a method of
calculation and solve for x. The patient will take 7.5 m L ondansetron
solution.
4. The MD changes the dose of the patient’s diltiazem hydrochloride to:
Diltiazem hydrochloride 180 mg PO every 12 hr.
The nurse is preparing to administer the new order and finds several
tablets labeled diltiazem hydrochloride ER 90 mg in the patient’s drawer.
Which action by the nurse is correct?
A. Call the MD to clarify the ordered dose.
B. Administer two 90 mg ER tablets to the patient.
C. Call the pharmacy to obtain the new dose.
D. Administer one 90 mg ER tablet for the morning dose.
ANS: C
Feedback
The nurse should call the pharmacist to obtain the new dose to
administer to the patient. The order does not need MD clarification.
, The nurse should not administer the 90 mg ER tablets because these are
“extended-release” tablets.
5. MD Order: Caduet (amlodipine 10 mg/atorvastatin 80 mg) 1 tablet PO
dail y. The nurse finds Caduet 10/40 mg tablets in the patient’s medication
drawer. What initial action by the nurse shows that safe medication
administration practice was demonstrated?
A. Using two patient identifiers before administering the ordered dose.
B. Administering two Caduet 10 mg/40 mg tablets to the patient.
C. Requesting the ordered dose from the pharmacy.
D. Splitting the tablet in half.
ANS: C
Feedback
Requesting the ordered dose from the pharmacy demonstrates safe
practice because Caduet 10 mg/80 mg is a fixed dose combination drug
and therefore must be administered as ordered. Using two patient
identifiers demonstrates safe practice and must be done after preparing
the dose and at the bedside before the administration of the medication.
Administering two Caduet 10 mg/40 mg tablets and splitting the tablet
will result in the administration of an incorrect dose.
6. MD Order: Vibram ycin syrup 75 mg PO BID. Pharmacy sends:
Vibram ycin syrup 25 mg/ 5 mL. The nurse measures the dose in the
medicine cup.
