HESI RN
RN Hesi Med Surg Dosage Calculations Questions
Extract:
Question 1 of 5
The healthcare provider prescribes amoxicillin 500 mg every 8 hours for a child who weighs 88 pounds. The recommended maximum safe dose is 50 mg/kg/24 hour. The available suspension is labeled, Amoxicillin Suspension 250 mg/5 mL. Based on this child weight, how many mL should the nurse administer ? (Enter numerical value only. (If rounding is required, round to the whole number.))
Correct Answer: 3
Rationale: Weight: 88 × 0.454 = 39.952 kg. Max safe dose: 50 mg/kg/day × 39.952 = 1997.6 mg/day. Per dose (3 doses/day): 1997.6 / 3 = 665.87 mg. Volume: 665.87 / (250 mg / 5 mL) = 2.6635 mL, rounded to 3 mL.
Question 2 of 5
An adult client receives a prescription for diphenhydramine 15 mL by mouth every 12 hours PRN for pruritus. The bottle is labeled, diphenhydramine 12.5 mg/5 mL. What is the total daily dose in mg that the client receives? (Enter numerical value only.)
Correct Answer: 75
Rationale:
To find the total daily dose, calculate the mg per dose: 12.5 mg/5 mL means 15 mL contains (12.5 × 15) / 5 = 37.5 mg. The prescription allows two doses daily (every 12 hours PRN), so 37.5 × 2 = 75 mg/day.
Question 3 of 5
A client receives a prescription for warfarin 2 mg IM daily. The pharmacy delivers a vial labeled, warfarin 5 mg/single-use vial. The instructions read, reconstitute with 2.7 mL of sterile water for injection to yield 2 mg/mL. How many mL should the nurse administer? (Enter the numerical value only.)
Correct Answer: 1
Rationale: Volume: 2 mg / 2 mg/mL = 1 mL.
Question 4 of 5
A pediatric client with cerebral palsy receives a prescription for a 75% enteral nutrition formula of 320 mL to infuse at 80 mL/hour via an enteral feeding pump. The formula is available full strength in a 240 mL can. To prepare the solution, the nurse should use how many mL of the enteral nutrition formula? (Enter numeric value only. If rounding is required, round to the nearest whole number.)
Correct Answer: 192
Rationale: For a 75% solution, let x = formula volume, y = water. x + y = 320 mL, x / 320 = 0.75. Solving, x = 0.75 × 320 = 240 mL formula, but adjusted for dilution: x = (3/2) y, x + y = 320, yields x = 192 mL formula.
Question 5 of 5
A client with a renal calculi receives a prescription for an intravenous infusion of 0.9% Sodium chloride Injection, USP 1,000 mL to be infused over 2.5 hours. The nurse should program the infusion pump to deliver how many mL/hour? (Enter numeric value only. If rounding is required, round to the nearest whole number.)
Correct Answer: 400
Rationale: Infusion rate = 1000 mL / 2.5 hours = 400 mL/hour.