Final answer:
To administer the correct dose of chlorpromazine to an adolescent weighing 110 lb, the nurse must firstly convert pounds to kilograms, then calculate the total dose in mg, and finally convert that to the volume in mL using the concentration of the syrup. The answer is 15 mL.
Step-by-step explanation:
To solve this medication dosage problem, we need to convert the patient's weight from pounds to kilograms and then calculate the correct volume of chlorpromazine syrup to administer. First, we convert the weight from pounds to kilograms by dividing by 2.2 (since 1 kilogram equals 2.2 pounds). Thus, a 110 lb adolescent weighs 110 lb / 2.2 lb/kg = 50 kg. Now, using the dosage of 0.55 mg/kg, we find the total dose required for a 50 kg adolescent which is 0.55 mg/kg × 50 kg = 27.5 mg.
Next, we must determine how many mL of the syrup to administer to deliver 27.5 mg of chlorpromazine. The concentration of the syrup is given as 10 mg/5 mL. To find the volume needed for the 27.5 mg dose, we can set up a proportion: (10 mg / 5 mL) = (27.5 mg / x mL). Solving for x gives us x mL = (27.5 mg × 5 mL) / 10 mg, which equals 13.75 mL. Therefore, the correct answer would be 15 mL when rounding up to the nearest whole number, since medicine dosages are typically not given in fractions.
As a nurse prepares to administer the medication, it's crucial that these steps are followed closely to ensure the correct dosage calculation and patient safety.