A nurse is caring for a client who has a prescription for amoxicillin 250 mg orally every 8 hr. Available is amoxicillin powder for oral suspension 200 mg÷5 mL. How many mL should the nurse administer per dose?

52 Step 1 is to divide the prescribed dose by the available concentration per unit volume, which is 250 mg ÷ (200 mg ÷ 5 mL). Step 2 is to simplify the available concentration fraction by dividing the mass by the volume, which is 200 mg ÷ 5 mL = 40 mg/mL. Step 3 is to divide the prescribed dose by this simplified concentration value, which is 250 mg ÷ 40 mg/mL = 6.25 mL. Step 4 is to round the final volume to the nearest tenth as per pediatric or standard liquid dosing guidelines, which yields 6.3 mL.