Question

The physician orders promethazine (Phenergan) 25 mg intramuscularly for a patient with nausea. The bottle is labeled "50 mg per ml." How much of the drug should be administered to the patient?

Answer 1

To administer the correct dosage of promethazine, which is 25 mg, one must inject 0.5 ml from a vial that has a concentration of 50 mg per ml.

Step-by-step explanation:

The physician orders promethazine (Phenergan) 25 mg intramuscularly for a patient with nausea. The bottle is labeled "50 mg per ml." To calculate the amount of drug to be administered, we use the following formula: Volume to administer (ml) = Dosage ordered (mg)/Concentration of stock (mg/ml). Substituting the known values gives us 25 mg / 50 mg/ml, which equals 0.5 ml. Therefore, 0.5 ml of the drug should be administered to the patient.