C H A P T E R 5
Mathematics and dosage calculations
59
C H E C K Y O U R U N D E R S T A N D I N G
Answers to the questions in this chapter can be found in
Appendix A at the back of this book.
MULTIPLE CHOICE
Select the best answer to the following.
1.
Digoxin 0.125 mg is ordered for a person who is
having trouble swallowing. The bottle of digoxin
elixir reads 0.5 mg/2 mL. How much would you
give?
a.
5 mL
b.
0.5 mL
c.
1.5 mL
d.
1 mL
2.
An order is written for 700 mg of ampicillin PO.
The drug is supplied in liquid form as 1 g/3.5 mL.
How much of the liquid should be given?
a.
5 mL
b.
2.5 mL
c.
6.2 mL
d.
2.45 mL
3.
An order is written for 1000 mL of normal saline to
be administered IV over 10 hours. The drop factor
on the IV tubing states 15 drops/mL. What is the IV
flow rate?
a.
50 mL/h at 50 drops/minute
b.
100 mL/h at 25 drops/minute
c.
100 mL/h at 100 drops/minute
d.
100 mL/h at 15 drops/minute
4.
A person needs to take 0.75 g of tetracycline PO.
The drug comes in 250-mg tablets. How many
tablets should the person take?
a.
2 tablets
b.
3 tablets
c.
4 tablets
d.
30 tablets
5.
Aminophylline is supplied in a 500 mg/2.5 mL
solution. How much would be given if an order were
written for 100 mg of aminophylline IV?
a.
5 mL
b.
1.5 mL
c.
2.5 mL
d.
0.5 mL
6.
Heparin 800 units is ordered for a person. The
heparin is supplied in a multidose vial that is labelled
10,000 units/mL. How many millilitres of heparin
would be needed to treat this person?
a.
0.8 mL
b.
0.08 mL
c.
8.0 mL
d.
0.4 mL
COMPLETE THE FOLLOWING PROBLEMS
1.
Change to equivalents within the system:
a.
100 mg = ______ g
b.
1500 g = ______ kg
c.
0.1 L = ______ mL
d.
500 mL = ______ L
2.
Convert to units in the household system:
a.
5 mL = ______ tsp
b.
30 mL = ______ tbsp
3.
Robitussin cough syrup 225 mg PO is ordered. The
bottle reads: 600 mg in 30 mL. How much cough
syrup should be given? ______ mL
4.
Ordered: 6.5 mg. Available: 10 mg/mL. Proper dose:
______ mL
5.
Ordered: 0.35 mg. Available: 1.2 mg/2 mL. Proper
dose: ______ mL
6.
Ordered: 80 mg. Available: 50 mg/mL. Proper dose:
______ mL
7.
Ordered: 150,000 units. Available: 400,000 units/
5 mL. Proper dose: ______ mL
