How many ml of diphenhydramine should a nurse administer to a 50 lb child based on a dose of 5mg/kg/day?

To determine the correct dosage of diphenhydramine for a 50 lb child based on the prescribed dosage of 5 mg/kg/day, one must first convert the child's weight from pounds to kilograms. The conversion factor is that 1 kg equals approximately 2.2 lbs. Therefore, the child's weight in kilograms can be calculated as follows:

50 lbs ÷ 2.2 = approximately 22.73 kg.

Next, to find the total daily dose of diphenhydramine required for the child, multiply the weight in kilograms by the dosage:

22.73 kg × 5 mg/kg/day = approximately 113.65 mg/day.

Since diphenhydramine comes in a liquid form (often with a concentration where 1 tsp (5 ml) contains 12.5 mg), the next step is to determine how many milliliters are needed for the calculated daily dose. If the medication concentration is known, the nurse would find that 12.5 mg/5 ml is equivalent to:

113.65 mg ÷ 12.5 mg = approximately 9.09 ml.

This total daily dose can then be rounded appropriately if necessary, and since it's typically administered in divided doses (for example,