A nurse is preparing to administer nafcillin 25 mg/kg IM to an adolescent who weighs 96 lb. Available is nafcillin injection 250 mg/mL. The nurse prepares to administer two injections. How many mL should the nurse administer per injection? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)

Calculation: Convert the adolescent's weight from pounds (lb) to kilograms (kg) using the conversion factor of 2.2 lb/kg. Patient's weight in kg = 96 lb / 2.2 lb/kg = 43.6363 kg. Calculate the total dose in milligrams (mg) for the adolescent. Total dose (mg) = Ordered dose (mg/kg) × Patient's weight (kg) = 25 mg/kg × 43.6363 kg = 1090.9075 mg. Available concentration = 250 mg/mL. Calculate the total volume in milliliters (mL) to be administered. Total volume (mL) = Total dose (mg) / Available concentration (mg/mL) = 1090.9075 mg / 250 mg/mL = 4.3636 mL. Calculate the volume per injection, as the total dose is divided into two injections. Volume per injection (mL) = Total volume (mL) / 2 = 4.3636 mL / 2 = 2.1818 mL. Round the answer to the nearest tenth. = 2.2 mL.