Reconstitution volume practice problems
Work each problem on paper first, rounding as the question says. Then open the answer to check it and see every step.
For study and exam practice, not for patient care. The orders in these problems are written for practice. In the clinic, follow the prescriber's order, your facility's protocols, and your pharmacy.
Problem 1
A client with a complicated intra-abdominal infection is prescribed meropenem 500 mg IV every 8 hours. The pharmacy supplies meropenem 1 g vial. The label says: for IV use, add 20 mL of Sterile Water for Injection to yield 50 mg/mL. How many mL should the nurse administer? Record your answer using a whole number.
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Answer: 10 mL
- mL = ordered dose ÷ concentration.
- 500 mg ÷ 50 mg/mL = 10 mL.
- 10 mL is exact, so no rounding is needed.
Problem 2
A client with a serious intra-abdominal infection is to receive meropenem by intravenous route. Order: meropenem 1 g IV every 8 hours. Available: meropenem 1 g vial. The label says: for IV use, add 20 mL of Sterile Water for Injection to yield 50 mg/mL. How many mL should the nurse administer? Record your answer using a whole number.
Show answer and steps
Answer: 20 mL
- Convert the order to the label's unit: 1 g = 1,000 mg.
- mL = ordered dose ÷ concentration.
- 1,000 mg ÷ 50 mg/mL = 20 mL.
- 20 mL is exact, so no rounding is needed.
Problem 3
The nurse is preparing an antibiotic for a client with a postoperative wound infection. Order: cefuroxime 750 mg IV every 8 hours. Available: cefuroxime 1.5 g vial. The label says: for IV use, add 16 mL of Sterile Water for Injection to yield 90 mg/mL. How many mL should the nurse administer? Record your answer using 1 decimal place.
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Answer: 8.3 mL
- mL = ordered dose ÷ concentration.
- 750 mg ÷ 90 mg/mL = 8.3333 mL.
- A volume of 1 mL or more is rounded to the nearest tenth: 8.3 mL.
Problem 4
A client with a lower respiratory tract infection is prescribed IV antibiotic therapy. Order: cefuroxime 1.5 g IV every 8 hours. Available: cefuroxime 1.5 g vial. The label says: for IV use, add 16 mL of Sterile Water for Injection to yield 90 mg/mL. How many mL should the nurse administer? Record your answer using 1 decimal place.
Show answer and steps
Answer: 16.7 mL
- Convert the order to the label's unit: 1.5 g = 1,500 mg.
- mL = ordered dose ÷ concentration.
- 1,500 mg ÷ 90 mg/mL = 16.6667 mL.
- A volume of 1 mL or more is rounded to the nearest tenth: 16.7 mL.
Problem 5
A client with a community-acquired respiratory infection is prescribed IV azithromycin. The prescription reads: azithromycin 500 mg IV daily. The pharmacy supplies azithromycin 500 mg vial. The label says: for IV use, add 4.8 mL of Sterile Water for Injection to yield 100 mg/mL. How many mL should the nurse administer? Record your answer using a whole number.
Show answer and steps
Answer: 5 mL
- mL = ordered dose ÷ concentration.
- 500 mg ÷ 100 mg/mL = 5 mL.
- 5 mL is exact, so no rounding is needed.
Problem 6
The nurse is caring for a client who has a prescription for cefoxitin 1 g, IV. The nurse has a 2 g vial of cefoxitin available. The label says: for IV use, add 10 mL of Sterile Water for Injection, Bacteriostatic Water for Injection, 0.9 percent Sodium Chloride Injection, or 5 percent Dextrose Injection to yield 180 mg/mL. How many mL should the nurse administer? Record your answer using 1 decimal place.
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Answer: 5.6 mL
- Convert the order to the label's unit: 1 g = 1,000 mg.
- mL = ordered dose ÷ concentration.
- 1,000 mg ÷ 180 mg/mL = 5.5556 mL.
- A volume of 1 mL or more is rounded to the nearest tenth: 5.6 mL.
Problem 7
Order: meropenem 500 mg IV every 8 hours. Available: meropenem 500 mg vial. The label says: for IV use, add 10 mL of Sterile Water for Injection to yield 50 mg/mL. How many mL should the nurse administer? Record your answer using a whole number.
Show answer and steps
Answer: 10 mL
- mL = ordered dose ÷ concentration.
- 500 mg ÷ 50 mg/mL = 10 mL.
- 10 mL is exact, so no rounding is needed.
Problem 8
A client with a lower respiratory tract infection is prescribed IV cefuroxime. The prescription reads: cefuroxime 750 mg IV every 8 hours. The available supply is a cefuroxime 750 mg vial. The label says: for IV use, add 8.3 mL of Sterile Water for Injection to yield 90 mg/mL. How many mL should the nurse administer? Record your answer using 1 decimal place.
Show answer and steps
Answer: 8.3 mL
- mL = ordered dose ÷ concentration.
- 750 mg ÷ 90 mg/mL = 8.3333 mL.
- A volume of 1 mL or more is rounded to the nearest tenth: 8.3 mL.
Problem 9
A client with a urinary tract infection needs an antibiotic given intravenously. Order: cefoxitin 1 g IV. Available: cefoxitin 2 g vial. The label says: for IV use, add 20 mL of Sterile Water for Injection, Bacteriostatic Water for Injection, 0.9 percent Sodium Chloride Injection, or 5 percent Dextrose Injection to yield 95 mg/mL. How many mL should the nurse administer? Record your answer using 1 decimal place.
Show answer and steps
Answer: 10.5 mL
- Convert the order to the label's unit: 1 g = 1,000 mg.
- mL = ordered dose ÷ concentration.
- 1,000 mg ÷ 95 mg/mL = 10.5263 mL.
- A volume of 1 mL or more is rounded to the nearest tenth: 10.5 mL.
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