A healthcare provider prescribes amoxicillin oral suspension at 100 mg per dose. The label reads 250 mg per 5 mL. How many milliliters are in one dose?

• A. 1 mL
• B. 2 mL
• C. 3 mL
• D. 4 mL

Answer: (B)

To dose using an oral suspension, first convert the concentration to mg per mL. The label has 250 mg in 5 mL, which equals 250/5 = 50 mg per mL. You need 100 mg per dose, so the required volume is 100 mg ÷ 50 mg/mL = 2 mL. A quick check: 2 mL × 50 mg/mL = 100 mg, which matches the prescribed dose. If you used 1 mL, you’d get 50 mg; 3 mL would be 150 mg; 4 mL would be 200 mg, all of which are incorrect for a 100 mg dose.