Examples · Reconstitution
Worked example
Reconstitution — practice problem 4
The prescriber orders 250 mg of cefazolin IV. The vial directs: add 5 mL of diluent to yield 125 mg/mL.
Ordered dose250 mg
After reconstitution125 mg/mL
Diluent5 mL
How many milliliters should the nurse draw up?
Answer: 2 mL
Step-by-step solution
1. Read the concentration after reconstitution
Add 5 mL diluent → 125 mg per 1 mL
2. Set up dimensional analysis so mg cancels
250 mg × ( 1 mL ÷ 125 mg )
3. Cancel mg and solve
= 250 ÷ 125 mL
= 2 mL
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