Worked example

Reconstitution — practice problem 7

The prescriber orders 50 mg of methylprednisolone IV. The vial directs: add 2.5 mL of diluent to yield 100 mg/mL.

Ordered dose50 mg
After reconstitution100 mg/mL
Diluent2.5 mL

How many milliliters should the nurse draw up?

Answer: 0.5 mL

Step-by-step solution

1. Read the concentration after reconstitution
Add 2.5 mL diluent → 100 mg per 1 mL
2. Set up dimensional analysis so mg cancels
50 mg × ( 1 mL ÷ 100 mg )
3. Cancel mg and solve
= 50 ÷ 100 mL
= 0.5 mL

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