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The physician has ordered 750 mg of Amoxicillin to be given PO QID X 10 days. The pharmacy has 0.5 g/1.5 ml available. What is the correct dosage in mL for this patient's dose?

A.

2.3 mL/dose

B.

1.2 mL/dose

C.

2.1 mL/dose

D.

1.7 mL/dose

Answer and Explanation

The Correct Answer is A

Step 1: Convert the available concentration to mg/mL

  • The pharmacy has 0.5 g in 1.5 mL.
  • 0.5 g = 500 mg.
  • So the concentration is 500 mg per 1.5 mL, which equals about 333 mg per 1 mL.

Step 2: Calculate the volume needed for the ordered dose

  • Ordered dose = 750 mg.
  • Volume = 750 ÷ 333 ≈ 2.25 mL.

Step 3: Match to the closest option

  • 2.25 mL rounds to 2.3 mL.

Correct Answer: 2.3 mL/dose


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Related Questions

Correct Answer is A

Explanation

A. 3.5 mL:The directions explicitly state: "For IM use, add 3.5mL sterile water for injection". This is the volume of diluent added to reconstitute the powder.

B. 250 mg/mL:This is the resulting concentration after the diluent has been added, not the volume of the diluent itself.

C. 1mL:This volume is too small and is an incorrect interpretation of the label. 1Ml is the volume that contains 250mg of the drug, but it is not the volume of diluent added.

D. 35 mL:This is 10 times the correct amount and is an incorrect reading of the label. Adding this much would severely dilute the medication.

Correct Answer is A

Explanation

Dimensional analysis:

  • Ordered dose: 8 mg IM.
  • Available concentration: 5 mg per 1 mL.
  • Volume needed = 8 mg × (1 mL / 5 mg) = 1.6 mL.

A. 3 mL:A 3 mL syringe is appropriate for IM injections and can accurately deliver 1.6 mL. It provides clear mL markings and enough capacity for the dose.

B. Insulin U-100:Insulin syringes are calibrated in insulin units, not mL, and are designed for subcutaneous insulin, not IM lorazepam.

C. Insulin U-50:Same issue as U-100; calibrated in units and not appropriate for IM medication administration.

D. 1 mL:A 1 mL syringe cannot hold the required 1.6 mL volume, so it is insufficient for this dose.

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