Wasting Morphine Medication Calculation Problem

[dukegurl]

Hey guys I wanted some help with this question: The doctor prescribes 4 mg of I.M. morphine every 3 hours for your patient's pain. The drug is available in a prefilled syringe containing 10 mg of morphine/mL. How many milliliters of morphine should you waste?

I understand that you should give 0.4mL to the patient but how much do you waste? If anybody could help me understand this part of the question I would really appreciate it. Thanks guys

[ComeTogether, LPN]

if there are 10mg in 1 mL each 0.1 mL has 1 mg morphine which equals 0.4mL given and 0.6mL wasted.