Worked example

Reconstitution - practice problem 9

The prescriber orders 500 mg of cefazolin IV. A 1 g vial directs: add 10 mL of diluent to yield 95 mg/mL.

Ordered dose500 mg
Vial1 g
Diluent10 mL
After reconstitution95 mg/mL

How many milliliters should the nurse draw up?

Answer: 5.26 mL

Step-by-step solution

1. Read the concentration after reconstitution
Add 10 mL diluent → 95 mg per 1 mL
2. Set up dimensional analysis so mg cancels
500 mg × ( 1 mL ÷ 95 mg )
3. Cancel mg and solve
= 500 ÷ 95 mL
= 5.26 mL

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