The provider orders amoxicillin 400 mg by mouth. The suspension on hand is labeled 250 mg/5 mL. How many milliliters should the medical assistant prepare?
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Answer: B
5 mL: 5 mL delivers only 250 mg, the strength per 5 mL, which is less than the 400 mg ordered.
8 mL: Correct. (Desired ÷ Have) × Quantity = (400 ÷ 250) × 5 mL = 1.6 × 5 = 8 mL.
3.1 mL: This inverts the ratio (250 ÷ 400 × 5) and would underdose the patient.
10 mL: 10 mL would deliver 500 mg, which is more than the 400 mg ordered.
Dose formula: (D ÷ H) × Q. Check: is the answer larger or smaller than the stock volume, as the ordered dose suggests?