A healthcare provider prescribes Ampicillin 125 mg/kg/day PO divided into doses every 8 hours for a child weighing 50lbs 8 oz. The pharmacy has Ampicillin suspension available as 250 mg/5mL. Using the safe dosing range and accurate conversions, what is the correct volume (in mL) of Ampicillin to administer per dose? Round to the nearest tenth.
Explanation & Rationale
Identify the child's weight and convert to total pounds Weight: 50 lbs 8 oz 8 oz / 16 oz = 0.5 lbs Total Weight = 50.5 lbs Convert weight to kilograms (kg) Weight in kg = 50.5 / 2.2 Weight in kg = 22.9545... kg Calculate the total daily dose in milligrams (mg) Ordered Dose: 125 mg/kg/day Total Daily Dose = 22.9545 kg * 125 mg/kg/day Total Daily Dose = 2,869.3125 mg/day Calculate the dose per administration (Frequency: every 8 hours) Doses per day = 24 / 8 = 3 doses Single Dose = 2,869.3125 mg / 3 Single Dose = 956.4375 mg Calculate the volume to administer in milliliters (mL) Available Concentration: 250 mg / 5 mL Volume = (Single Dose / Available mg) * Available Volume Volume = (956.4375 / 250) * 5 Volume = 3.82575 * 5 = 19.128... mL Round to the nearest tenth 19.128... rounded = 19.1 = 19.1 mL