A nurse prepares to administer morphine 4 mg IM at 0800. Available is morphine injection 10 mg/mL. How many mL should the nurse administer per dose?

Question

(If rounding is necessary, round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero. Do not include the unit of measure (ex. mg, ml, etc) __________mL

Answer 1

The formula is Dose Ordered/ Dose in hand X Quantity

4/10 *1= 4/10= 0.4ml

4 is the dose ordered, 10 is the dose in hand and 1 ml is the quantity.

Answer 2

I like to have my students think of it this way:

1. The dose you need: 4mg
2. What you have on hand: 10mg/1mL (concentration)
3. Note that the volume you are looking for will be less than 1mL because 4 < 10 (easily self check)

1. 4mg/xmL = 10mg/1mL
2. Cross multiply and you get 4 = 10x
3. To get what you are looking for (x), you need to solve for x. To do this divide each side by 10
4. 4/10 = 10x/10
5. The 10s on the right side of the equal sign cancel out, therefore your answer is what you get after dividing 4 by 10
6. Answer = 0.4mL

Answer 3

0.4 mL

10mg = 1mL

1mg = 0.1mL

4mg = 0.4mg

Follow the logic?