Morphine 2mg Prn pain Supply Morphine in a 20 ml multi dose

Morphine 2mg Prn pain. Supply: Morphine in a 20 ml multi dose vial. Each ml contains 15 mg of Morphine.

How many ml will the nurse administer?

Solution

Each mL contains 15 mg of Morphine

So, we need to find how many mL will 2mg contain

1 mL ---> 15 mg
x mL ---> 2mg

Using the method of ratios :
1/x = 15/2
1/x = 7.5
x = 1/7.5
x = 10/75
x = 2/15 mL

2/15 mL needed