A child weighs 77 pounds and is prescribed amoxicillin 70 mg/kg/day divided into two doses. How many milligrams should be given per dose?

A child weighs 77 pounds and is prescribed amoxicillin 70 mg/kg/day divided into two doses. How many milligrams should be given per dose?

• A. 875 mg
• B. 2450 mg
• C. 1225 mg
• D. 615 mg

Answer: (C)

Calculating a weight-based antibiotic dose requires converting weight to kilograms, then applying the mg/kg/day dose, and finally dividing by how many times per day the dose is given. Convert weight to kilograms: 77 lb ÷ 2.2046 ≈ 34.9 kg. Total daily dose: 34.9 kg × 70 mg/kg/day ≈ 2445 mg/day. Per dose (divided into two doses): 2445 mg ÷ 2 ≈ 1222 mg per dose, which rounds to 1225 mg. So you should give about 1225 mg per dose.

Calculating a weight-based antibiotic dose requires converting weight to kilograms, then applying the mg/kg/day dose, and finally dividing by how many times per day the dose is given.

Convert weight to kilograms: 77 lb ÷ 2.2046 ≈ 34.9 kg.

Total daily dose: 34.9 kg × 70 mg/kg/day ≈ 2445 mg/day.

Per dose (divided into two doses): 2445 mg ÷ 2 ≈ 1222 mg per dose, which rounds to 1225 mg.

So you should give about 1225 mg per dose.