HESI Dosage Calculations Practice Exam, Hesi Pharmacology Review (Grade A+)

HESI Dosage Calculations Practice Exam, Hesi Pharmacology Review (Grade A+) 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. 4. A client with a Trichomonas vaginalis infection receives a prescription for metronidazole (Flagyl) 1 gram. The medication is available in 500 mg tablets. How many tablets should the nurse administer? (Enter numeric value only.) Correct calculation 1 gram = 1000 mg 1 tablet :: 500 mg = X tablets :: 1000 mg X = 1000/500 = 2 tablets 5. A client is receiving an IV solution of 2 grams of medication diluted in 100 ml of normal saline over a one hour time period. How many mg of medication is the client receiving per minute? (Enter numeric value only. If rounding is required, round to the nearest whole number.) Correct calculation 2 grams = 2000 mg 1 hour = 60 minutes 2000 mg/60 minutes = 33.333 mg/minute, rounded to 33 mg/minute 6. The healthcare provider prescribes propofol (Diprivan) at 8 mcg/kg/minute for a client during conscious sedation. The drug is dispensed as 100 mg/50 ml 0.9% normal saline. The client's weight is 198 pounds. 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 tenth.) Correct calculation The client's weight in kg is 90 kg (198 pounds / 2.2 pounds). Next, determine the total mcg in the NS infusion (1 mg : 1000 mcg :: 100 mg : 100,000 mcg) and the IV concentration per ml (100,000 mcg : 50 ml :: X mcg : 1 ml). 100,000 / 50 = 2000 mcg/ml. Then, calculate the prescribed dose (mcg/kg/min) x 60 min/hour x kilograms divided by concentration (mcg/ml). 8 x 90 x 60 divided by 2000 = 21.6 ml/hour 7. The healthcare provider prescribes an intermittent infusion of nafcillin (Unipen) 800 mg IV for a pediatric client. The drug is dispensed in a concentration of 250 mg/ml, and the recommended infusion concentration is 40 mg/ml. When adding the prescribed dose to the volume control device, how many ml of IV solution should the nurse add to dilute? (Enter numeric value only. If rounding is required, round to the nearest tenth.) Correct calculation First, calculate the amount of milliliters of medication needed to provide 800 mg of nafcillin. Prescribed dose (800 mg) divided by dose on hand (250 mg/ml) equals 3.2 ml Next, determine the recommended concentration using equivalent fractions. 800 mg/X = 40 mg/1 ml 40X = 800 = 20 ml (the total volume at the recommended concentration) 20 ml (total volume) minus the 3.2 ml (800 mg dose) equals an additional 16.8 ml of fluid to be added to the volume control device to obtain the recommended concentration.