A patient is prescribed aspirin 650 mg every 12 hours. With 325 mg tablets, how many tablets are needed per day?

A patient is prescribed aspirin 650 mg every 12 hours. With 325 mg tablets, how many tablets are needed per day?

• A. 2 tablets
• B. 3 tablets
• C. 4 tablets
• D. 5 tablets

Answer: (C)

Calculating the number of tablets comes from matching the prescribed amount per dose to the tablet strength and multiplying by how many doses occur in a day. Each dose is 650 mg and each tablet is 325 mg, so you need 650 ÷ 325 = 2 tablets for one administration. Since it’s given every 12 hours, there are two administrations daily, so 2 tablets per dose × 2 doses per day = 4 tablets daily. (You can also check by total daily amount: 650 mg × 2 doses = 1300 mg per day; 1300 mg ÷ 325 mg per tablet = 4 tablets.) Four tablets per day.

Calculating the number of tablets comes from matching the prescribed amount per dose to the tablet strength and multiplying by how many doses occur in a day. Each dose is 650 mg and each tablet is 325 mg, so you need 650 ÷ 325 = 2 tablets for one administration. Since it’s given every 12 hours, there are two administrations daily, so 2 tablets per dose × 2 doses per day = 4 tablets daily. (You can also check by total daily amount: 650 mg × 2 doses = 1300 mg per day; 1300 mg ÷ 325 mg per tablet = 4 tablets.) Four tablets per day.