HESI Dosage Calculations Practice Exam

1. Amoxicillin 500 mg PO every 8 hours is prescribed for a client with an infection. The drug is available in a suspension of 125 mg/5ml. How many ml should the nurse administer with each dose? Correct calculation 500 : X :: 125 : 5 125X = 2,500 X = 20 ml 2. Oxytocin (Pitocin) 4 milliunits/min is prescribed for a client with an ineffective contraction pattern. To administer the prescribed dosage, the nurse adds 20 units of oxytocin to 1,000 ml of Ringer's Lactate. The infusion pump should be set to deliver how many ml/hour? (Enter numeric value only.) Correct calculation 4 milliunits/min x 1 unit/1000 milliunits x 1000 ml/20 units x 60 min/hr =240,000/20,000 = 12 ml/hr 3. The healthcare provider prescribes the adjustment of the IV hourly rate based on the nasogastric tube (NGT) output q4h for a client who had abdominal surgery yesterday. From 1200 to 1600, the NGT output was 240 ml, and the IV of D5W 0.45% NS was infused at a rate of 100 ml/hour. At 1600 the nurse should regulate the IV to deliver how many ml/hour to replace this fluid loss? (Enter numeric value only.) Correct calculation To calculate the hourly rate of IV fluid replacement based on the last 4 hours of NGT output, the nurse should calculate an average hourly output by dividing 240 ml by 4 hours = 60 ml NGT output q1h. The nurse should then add the 60 ml loss per hour to the present infusion rate of 100 ml/hr, totaling an infusion rate of 160 ml/hour for the next 4 hours.