McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 5  Mathematics and dosage calculations

C H E C K Y O U R U N D E R S T A N D I N G

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

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

c. 8.0 mL d. 0.4 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

COMPLETE THE FOLLOWING PROBLEMS

b. 2.5 mL c. 6.2 mL d. 2.45 mL

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. 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?

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

a. 2 tablets b. 3 tablets c. 4 tablets d. 30 tablets