Worked example

Reconstitution - practice problem 12

The prescriber orders 40 mg of methylprednisolone IV. A 40 mg vial directs: add 1 mL of diluent to yield 40 mg/mL.

Ordered dose40 mg
Vial40 mg
Diluent1 mL
After reconstitution40 mg/mL

How many milliliters should the nurse draw up?

Answer: 1 mL

Step-by-step solution

1. Read the concentration after reconstitution
Add 1 mL diluent → 40 mg per 1 mL
2. Set up dimensional analysis so mg cancels
40 mg × ( 1 mL ÷ 40 mg )
3. Cancel mg and solve
= 40 ÷ 40 mL
= 1 mL

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