Final answer:
To find the correct volume, a simple proportion is used. For the provided concentration of 500 mg/mL, the calculation would result in 0.15 mL. However, this appears incorrect for the given options. Assuming a typo and a correct concentration of 50 mg/mL, the volume would be 1.5 mL.
Step-by-step explanation:
To determine how many milliliters of Demerol should be administered, we need to convert the dosage from milligrams (mg) to milliliters (mL) using the concentration given on the drug label. The label states that the concentration is 500 mg/mL, which means each milliliter contains 500 mg of Demerol.
Starting with the physician's order for 75 mg of Demerol, we can set up a simple proportion to find out the volume in milliliters:
75 mg Demerol x (1 mL / 500 mg) = (75 / 500) mL
Calculating this gives us:
75/500 = 0.15 mL
Therefore, 0.15 milliliters should be administered. However, since this is not one of the options provided, there seems to be a typo in the question. The correct concentration should likely be 50 mg/mL to match a provided answer choice.
So, with the corrected concentration of 50 mg/mL:
75 mg Demerol x (1 mL / 50 mg) = (75 / 50) mL
Calculating this gives us:
75/50 = 1.5 mL
So, with the corrected concentration, the correct answer would be 1.5 mL, which matches one of the options.
Note: Always verify drug concentrations and calculation before administration, as medication errors can have serious consequences.