Worked example

Oral dose - tablets - practice problem 9

The prescriber orders 20 mg of lisinopril PO. The pharmacy stocks lisinopril in 40 mg tablets.

Ordered dose20 mg

On hand40 mg per tablet

How many tablets should the nurse give?

Answer: 0.5 tablets

Step-by-step solution

1. Identify what you have and what you want

Have: 40 mg per tablet · Want: 20 mg

2. Set up dimensional analysis so mg cancels

20 mg × ( 1 tablet ÷ 40 mg )

3. Cancel mg and solve

= ( 20 × 1 ) ÷ 40 tablet

= 0.5 tablets