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: 10
Rationale:
To determine the volume to administer, first convert the child's weight from pounds to kilograms: 88 pounds × 0.454 kg/pound = 39.952 kg (rounded to 40 kg). The safe dose is 50 mg/kg/24 hours, so 50 × 40 = 2000 mg/day. The prescribed dose is 500 mg every 8 hours, or 500 × 3 = 1500 mg/day, which is safe. The suspension is 250 mg/5 mL. Set up a proportion: 250 mg / 5 mL = 500 mg / x mL. Solving, x = (500 × 5) / 250 = 10 mL.
Question 2 of 5
A client receives a prescription for 1 liter of lactated Ringer's intravenously (IV) to be infused over 12 hours. The IV administration set delivers 60 gtt/mL. How many gtt/min should the nurse regulate the infusion? (Enter numerical value only. If rounding is required, round to the nearest whole number.)
Correct Answer: 83
Rationale: Volume = 1000 mL, drop factor = 60 gtt/mL, time = 12 hours = 720 minutes. Flow rate = (1000 × 60) / 720 = 83.333 gtt/min, rounded to 83.
Question 3 of 5
A client returns from the PACU with a bag of IV fluids that has 630 mL remaining in the 1,000 mL bag. The prescription reads, 'Continue the present IV over the next 7 hours.' The IV administration set delivers 10 gtt/mL. The nurse should regulate the infusion to deliver how many drops/minute to accomplish the new prescription? (Enter numeric value only.)
Correct Answer: 15
Rationale: Flow rate = (630 mL × 10 gtt/mL) / (7 × 60) = 15 gtt/min.
Question 4 of 5
The healthcare provider prescribes lamivudine oral solution 150 mg twice daily for a client who is HIV positive. The available bottle contains 240 mL of lamivudine labeled, '10 mg/mL.' How many mL should the nurse administer in a 24 hour period? (Enter numeric value only.)
Correct Answer: 30
Rationale: Dose per administration: 150 mg / (10 mg/mL) = 15 mL. Daily volume: 15 × 2 = 30 mL.
Question 5 of 5
A child who weighs 42 kg receives a prescription for methylprednisolone succinate 1.5 mg/kg/day intravenously in divided doses every 6 hours. The medication is available in 40 mg/mL vials. How many mL should the nurse administer with each dose? (Enter numerical value only. If rounding is required, round to the nearest tenth.)
Correct Answer: 0.4
Rationale: Daily dose: 1.5 mg/kg/day × 42 = 63 mg/day. Per dose (every 6 hours, 4 doses/day): 63 / 4 = 15.75 mg. Volume: 15.75 / 40 = 0.39375 mL, rounded to 0.4 mL.