A physician orders amoxicillin 50 mg/mL for a child at 1 mL PO q8h for 10 days. What is the total volume to be dispensed, in mL, if the amoxicillin stock is 125 mg/5 mL?

C. 60

C. 60

First, find how many mg the child should receive per day according to the instructions. Taking 1 mL of 50 mg/mL amoxicillin q8h means that the child will be taking 50 mg every 8 hours, or three times a day:

50 mg per dose x 3 doses per day = 150 mg per day

Since the stock amoxicillin contains 125 mg per 5 mL, this means that the stock contains 25 mg per mL. Divide 150 mg per day by 25 mg/mL to find how many mL are required per day:

150 mg per day ÷ 25 mg/mL = 6 mL per day

Finally, multiply the total mL required per day by the total days of therapy to find how many mL are needed to complete the course:

6 mL per day x 10 days of therapy = 60 mL total