Examples · Reconstitution
Worked example
Reconstitution - practice problem 2
The prescriber orders 500 mg of cefazolin IM. A 1 g vial directs: add 2.5 mL of diluent to yield 330 mg/mL.
Ordered dose500 mg
Vial1 g
Diluent2.5 mL
After reconstitution330 mg/mL
How many milliliters should the nurse draw up?
Answer: 1.52 mL
Step-by-step solution
1. Read the concentration after reconstitution
Add 2.5 mL diluent → 330 mg per 1 mL
2. Set up dimensional analysis so mg cancels
500 mg × ( 1 mL ÷ 330 mg )
3. Cancel mg and solve
= 500 ÷ 330 mL
= 1.52 mL
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