Worked example

Reconstitution - practice problem 13

The prescriber orders 40 mg of methylprednisolone IV. The vial directs: add 2 mL of diluent to yield 125 mg/mL.

Ordered dose40 mg
After reconstitution125 mg/mL
Diluent2 mL

How many milliliters should the nurse draw up?

Answer: 0.32 mL

Step-by-step solution

1. Read the concentration after reconstitution
Add 2 mL diluent → 125 mg per 1 mL
2. Set up dimensional analysis so mg cancels
40 mg × ( 1 mL ÷ 125 mg )
3. Cancel mg and solve
= 40 ÷ 125 mL
= 0.32 mL

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