NCLEX Dosage Calculation Practice Questions (Part 1: 20 Items)

NCLEX Dosage Calculation Practice Questions (Part 1: 20 Items)A 1. 1. Question You are caring for a patient at home who must take magnesium hydroxide/aluminum hydroxide (Maalox) 30 mL PO. How will you instruct the patient to measure the dose using ordinary household measuring devices? Fill in the blanks. Record your answer to the nearest whole number. o Answer: (2) tbsp. Incorrect Correct answer: • 2 tbsp. Rationale: • One tablespoon is equal to 15 mL. • Convert 30 mL to tablespoons by multiplying it by one tablespoon. • Then, divide 30 by 15 mL to get the final answer of 2 tbsp. Computation: 2. 2. Question A patient has a bottle of warfarin (Coumadin) 5 mg tablets at home. After his most recent international normalized ratio (INR), the doctor calls and tells him to take 7.5 mg/day. How many tablets (scored) should the patient take? Fill in the blanks and record your answer using one decimal place. • Answer: (1.5) tablet(s) Incorrect Correct answer: • 1.5 tablet Formula: Rationale: • Use the standard formula above. • First, multiply the desired dose (7.5 mg) to the vehicle (1 tablet) to get 7.5mg. • Then, divide 7.5 mg by the drug on hand (5 mg) to get 1.5 tablets. Computation: 3. 3. Question You have an IVPB of ranitidine (Zantac) 50 mg in 50 mL D5W to run over 30 minutes. The tubing has a drip factor of 15. How many drops per minute will you set on the IV infusion controller? Fill in the blanks. • Answer: (25) gtts/minute Incorrect Correct answer: • 25 gtts/minute Formula: Rationale: • Use the IV flow rate formula for gtts/minute above. • Multiply 50 mL (total volume) to 15 gtts (drop factor) to get 750 gtts. • Divide 750 gtts with 30 minutes (time in minutes) to get 25 gtts/minute. Computation: 4. 4. Question The physician orders alprazolam (Xanax) 0.5 mg PO. You have on hand Xanax 0.25 mg tablets. How many tablet(s) will you give? Fill in the blanks. • Answer: (2) tablets(s) Incorrect Correct answer: • 2 tablets Formula: Rationale: • Use the standard formula above. • Multiply 0.5 mg to 1 tablet (vehicle) to get 0.5 mg. • Then divide 0.5 mg with 0.25 units (drug on hand) to get 2 tablets. Computation: 5. 5. Question You need to administer 250 mg of erythromycin (Erythrocin) PO. You have on hand 0.5 g tablets. How many tablet(s) will you give? Fill in the blanks. • Answer: (1/2,0.5) tablet(s) Incorrect Correct answer: • 1/2 tablet or 0.5 tablet Formula: Rationale: • 1 g is equal to 1000 mg. • Convert 250 mg to grams first by multiplying 250 mg to 1 g, then divide the answer by 1000 mg to get 0.25 g. • Then use the standard formula above. • Multiply 0.25 g (desired dose) to 1 tablet (vehicle) to get 0.25 g. • Finally, divide 0.25 g by 0.5 g (drug on hand) to get 0.5 g or ½ tablet. Computation: 6. 6. Question You have available lorazepam (Ativan) 0.5 mg tablets, and you need to administer 1 mg PO. How many tablet(s) will you administer? Fill in the blanks. • Answer: (2) tablet(s) Incorrect Correct answer: • 2 tablets Formula: Rationale: • Use the standard formula above. • Multiply 1 mg (desired dose) to 1 tablet (vehicle) to get 1 mg. • Then, divide 1 mg by 0.5 mg (drug on hand) to get 2 tablets. Computation: 7. 7. Question A patient with heart failure has a daily order for digoxin (Lanoxin) 0.25 mg PO. Digoxin 0.125 mg tablets are available. How many tablet(s) should you give? Fill in the blanks. • Answer: (2) tablet(s) Incorrect Correct answer: • 2 tablets Formula: Rationale: • Use the standard formula above. • Multiply 0.25 mg (desired dose) to 1 tablet (vehicle) to get 0.25 mg. • Divide 0.25 mg by 0.125 mg (drug on hand) to get 2 tablets. Computation: 8. 8. Question The physician writes a “now” order for codeine 45 mg IM for a patient with a vertebral compression fracture. You have on hand codeine 60 mg/2 mL. How many milliliters should you give? Fill in the blanks and record your answer using one decimal place. • Answer: (1.5) ml Incorrect Correct answer: • 1.5 mL Formula: Rationale: • Use the standard formula above. • Multiply 45 mg (desired dose) to 2 mL (vehicle) to get 90 mL. • Divide 90 mL by 60 mg (drug on hand) to get 1.5 mL. Computation: 9. 9. Question You have on hand hydromorphone (Dilaudid) 4 mg/mL. You need to administer 0.015 mg/kg to a patient who weighs 150 pounds. How many milliliters should you administer? Fill in the blanks. Record your answer using two decimal places. • Answer: (0.26) ml Incorrect Correct answer: • 0.26 ml Formula: Rationale: • 1 kg is equal to 2.2 lbs. • Convert 150 lbs to kilograms by dividing it with 2.2 to get 68.18 kg. • Then, multiply 68.18 kg with 0.015 mg/kg to get 1.022 mL. • Use the standard formula above to get the amount to be administered. • Multiply 1.022 mL to 1 mL, then divide it by 4 mg to get 0.255 mL. • Finally, round it off to two decimal places to get 0.26 mL. Computation: 10. 10. Question You have an order to administer 40 mg of methadone (Dolophine) SC for opioid detoxification. You have on hand 30 mg/mL. How much should you draw into the syringe? Fill in the blanks. Record your answer using one decimal place. • Answer: (1.3) ml Incorrect Correct answer: • 1.3 ml Formula: Rationale: • Use the standard formula above. • Multiply 40 mg (desired dose) to 1 mL (vehicle) to get 40 mL. • Then, divide 40 with 30 mg (drug on hand) to get 1.3 mL. Computation: 11. 11. Question A patient has a primary IV of dextrose in water 1,000 mL to be infused over 24 hours. What would be the drip rate (gtts/min) using tubing with a drop factor of 60? Fill in the blanks and record your answer using a whole number. • Answer: (42) gtts/minute Incorrect Correct answer: • 42 gtts/minute Formula: Rationale: • Use the intravenous (IV) flow rate formula for gtts/minute above. • Multiply 1000 mL (total volume) to 60 gtts (drop factor) to get 60,000. • Then, divide 60,0000 with 1,440 minutes (24 hours) to get 41.6 gtts. • Finally, round it off to a whole number to get 42 gtts/minute. Computation: 12. 12. Question Your patient needs 2,000 mL of saline IV over 4 hours for severely deficient fluid volume. How many milliliters per hour will you set on a controller? Fill in the blanks. • Answer: (500) ml/hr Incorrect Correct answer: • 500 ml/hr Formula: Rationale: • Use the IV flow rate formula for mL/hour above. • Divide 2000 mL (total volume) with 4 hours (number of hours to run) to get 500mL/hour. Computation: 13. 13. Question Your patient needs 2,000 mL of D5W IV over 24 hours, to be delivered with tubing set with a drop factor of 15. How many drops per minute will you set for an infusion rate? Fill in the blank and round to the nearest whole number for your final answer. • Answer: (21) gtts/minute Incorrect Correct answer: • 21 gtts/minute Formula: Rationale: • Use the IV flow rate formula for gtts/minute above. • Multiply 2000 mL (total volume) to 15 gtts (drop factor) to get 30,000. • Divide 30,000 with 1440 minutes (time in minutes) to get 20.8 gtts. • Finally, round off to a whole number to get 21 gtts/minute (always round up when dealing with IV flow rates because you can’t administer half a drop). Computation: 14. 14. Question You need to administer furosemide (Lasix) 2 mg/minute via continuous IV infusion on a controller. Pharmacy has sent a bag of Lasix 400 mg diluted in D5W 250 mL. How many milliliters per hour will you set on the controller? Fill in the blanks. • Answer: (75) ml/hr Incorrect Correct answer: • 75 ml/hr Formulas: Standard Formula: Infusion Time (in hours): Rationale: • Use the standard formula first and then the IV flow rate formula for mL/hr as shown above. • First, multiply 2 mg (desired dose) to 250 mL (vehicle) to get 500 mg. • Divide 500 mg with 400 mg to get 1.25 mg. • Then, multiply 1.25 mg with 60 minutes to get 75 mL. • Finally, divide 75 mL by 1 hour to get 75 mL/hour Computation: 15. 15. Question The physician orders an IV with heparin at 700 units/hour. You have a bag with 100 units/mL of solution. How many milliliters per hour will you set on the IV infusion controller? Fill in the blanks. • Answer: (7) ml/hour Incorrect Correct answer: • 7 ml/hour Formula: Standard Formula: Infusion Time (in hours): Rationale: • Use the standard formula first then the IV flow rate formula for mL/hour. • Multiply 700 units (desired dose) to 1 mL (vehicle) to get 700 mL. • Divide 700 units with 100 units (drug on hand) to get 7 mL. • Finally, divide 7 mL by 1 hour to get 7 mL/ hour. Computation: 16. 16. Question A 12-year-old child was admitted to the emergency department because of an asthma attack. Upon assessment, you found out that the child’s weight measures 82.4 lbs. The primary care provider ordered 2 mg/kg of methylprednisolone (Solu-Medrol). The available stock dose is 125 mg/2mL. How many mL will the nurse administer? Fill in the blank and record round off your final answer using one decimal place. • Answer: (1.2) milliliters (mL). Incorrect Correct answer: • 1.2 mL Formula: Rationale: • First, convert weight in lbs to kilograms (1 kg is equal to 2.2 lbs): 82.4 lbs divided by 2.2 lbs/kg to get 37.45 kg (37.5 kg). Always round off lbs to kg conversions to the nearest tenths before proceeding with the rest of the problem. • Compute for the required dosage by multiplying weight in kg to weight per dosage: 37.5 kg multiplied by 2 mg/kg to get 75 mg. • Using the standard formula: divide 75 mg (desired) by 125 (on hand) mg then multiply 2 mL (vehicle) to get 1.2 mL which is your final answer. Computation: 17. 17. Question A health care provider orders amoxicillin syrup to a 3-year-old child with UTI. Your assessment reveals the following data: • Temperature of 38.5º C • Heart rate of 88 bpm • Respiratory rate of 30 bpm • Blood pressure of 90/50 • Height of 98 cm • Weight 12 kg (26.4 lbs) The dosage required as per order is 50 mg/kg/day divided into 3 doses per day (TID). Available stock is a suspension with a concentration of 400 mg/5mL. How much will you administer per dose? Fill in the blank and record your answer using one decimal place. • Answer: (2.5) mL Incorrect Correct Answer: • 2.5 mL Formula: Rationale: • Calculate the whole dose per day by multiplying the child’s weight and order: 12 kg multiplied by 50 mg/kg/day will get you 600 mg per day. • Divide the dose per day with required frequency (TID): 600 mg/day divided by 3/day to get 200 mg per dose. • Next, use the standard formula to calculate for the desired dosage: 200 mg/400 mg multiplied by 5 mL to get 2.5 mL. Computation: 18. 18. Question A patient with ventricular fibrillation is prescribed with bretylium 5 mcg/kg/minute. The medication comes mixed 50 mg in 50 mL of 0.9 % normal saline. The patient’s weight is 170 lbs. How much of the medication will you administer per hour? Fill in the blank and round off your final answer to a whole number. • Answer: (23) mL/hour Incorrect Correct answer: • 23 mL/hour Formula: Rationale: • Convert the patient’s weight from lbs to kg. Divide 170 by 2.2 kg to get 77.3 kg (77.27 kg). Always round off lbs to kg conversions to the nearest tenths before proceeding with the rest of the problem. • Next, determine the correct dosage based on the weight of the patient. Multiply 77.3 kg to 5 mcg/kg/min to get 386.5 mcg/minute. • Convert the equivalent ordered (mcg) to the unit measurement on hand (mg) by dividing 386.35 mcg/minute with 1,000 mcg per 1 mg –– or by moving the decimal place three digits to the left – to get 0.3865 mg/minute. • Use the standard formula to calculate for the desired dose. Divide 0.3865 mg/minute to 50 mg to get 0.00773/minute then multiply to 50 mL to get 0.38635 mL/minute – you can actually cancel out the 50 and still get the same answer (this lengthy process is done for visualization purposes). • Next, multiply 0.38635 mL/minute to 60 minutes/hour to get 23.19 mL/hour • Finally, round off your answer to the nearest whole number to get 23 mL/hour. Computation: 19. 19. Question A client suffering from chest discomfort and shortness of breath is brought to the emergency department due to acute angina pectoris. The healthcare provider orders IV nitroglycerin (Nitroglycerin) 75 mg in 500 mL of 5% Dextrose Water at 100 mcg/min. The nurse will set the pump at which rate (mL/hr)? Fill in the blank and write your answer using a whole number. • Answer: (40) mL/hr Incorrect Correct Answer: • 40 mL/hr Formula: Rationale: • First, you need to convert 100 mcg/min to mg by moving the decimal point three digits to the left – alternatively, you can divide 100 mcg with 1000 – to get 0.1 mg/min. • Use the standard formula to calculate for the desired dose. Divide the desired dose of 0.1 mg/min to 75 mg (stock dose) to get 0./min the multiply it to the 500 mL to get 0.66 mL/min. • Finally, calculate for the mL/hr by multiplying 0.66 mL/min to 60 min/hour to arrive at the final answer of 40 mL/hr. Computation: 20. 20. Question A primary healthcare provider ordered ceftriaxone (Rocephin) for a 4-year old child with lower respiratory tract infection. The dose required is 20 mg/kg/day divided twice a day, administered per dose via IV. The child’s weight is 29 lbs. The drug comes prediluted in a concentration of 10mg/ml. How much of the medication will you administer in mL? Fill in the blank and record your final answer using one decimal place. • Answer: (13.2) mL Incorrect Correct Answer: • 13.2 mL. Formula: Rationale: • Convert the patient’s weight from lbs to kg: Divide 29 by 2.2 kg to get 13.2 kg (13.18 kg). Always round off lbs to kg conversions to the nearest tenths before proceeding with the rest of the problem. • Calculate the dosage in milligrams (mg) by multiplying the patient’s weight of 13.2 kg to 20 mg/kg/day to get 264 mg/day • Next, divide the dosage with its ordered frequency of two times a day: 264 mg/day divided by 2 to get 132 mg per dose. • Using the standard formula, calculate for the desired dosage: 132 mg divided by 10 mg to get 13.2 then multiply by 1 mL to get 13.2 mL. Calculations: