Question

"You receive the following prescription:

Cephalexin 250 mg/5 mL susp
1 tsp po QID x 14 days
Which stock bottle size of cephalexin suspension should be dispensed to complete the therapy?"

a) 120 mL

b) 240 mL

c) 360 mL

d) 480 mL

Answer 1

The correct stock bottle size to dispense for the 14-day therapy of cephalexin 250 mg/5 mL suspension, taken 1 tsp QID, is 360 mL, as the total volume needed for the duration is 280 mL.

Step-by-step explanation:

To determine which stock bottle size of cephalexin suspension should be dispensed to complete the therapy, we need to calculate the total volume of medication the patient will require over the course of 14 days. The prescribed dose is 1 teaspoon (tsp) taken orally four times a day (QID). Knowing that 1 teaspoon is equal to 5 milliliters (mL), we can calculate the daily volume needed and then the total volume for 14 days.

First, calculate the daily volume needed: 1 tsp/dose × 5 mL/tsp × 4 doses/day = 20 mL/day.

Then, calculate the total volume for 14 days: 20 mL/day × 14 days = 280 mL.

Since the total volume required is 280 mL, the closest stock bottle size that would provide enough medication to complete the therapy without having too much excess would be:

Option c) 360 mL