Drug Dosage Calculations NCLEX Exam 3

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1. You need to administer prochlorperazine (Compazine) 10 mg IM to a nauseated patient. You have on hand Compazine 5 mg/mL. How should you prepare the correct dose?

5 mL
2 mL
1 mL
0.5 mL

2. An order reads furosemide (Lasix) 40 mg IV push. You have on hand Lasix 20 mg/2 mL. How should you prepare the correct dose?

4 mL
2 mL
1 mL
0.5 mL

3. You need to administer 15 mg of morphine IM. It is supplied as gr 1/6 per mL. How should you prepare the correct dose?

4.5 mL
4 mL
2 mL
1.5 mL

4. You have on hand diazepam (Valium) 5 mg/mL. You need to administer 8 mg IV push stat. to a patient having a seizure. How much should you draw into the syringe?

0.6 mL
1 mL
1.6 mL
2 mL

5. A patient has an aminophylline IV drip ordered for acute asthma, to run at 20 mL/hour. No IV infusion controller is available right now. How many drops per minute will be required if microdrip tubing is used?

30 gtts/min
20 gtts/min
15 gtts/min
10 gtts/min

6. A safe maintenance dose of aminophylline is 0.36 mg/kg/hour. It is supplied as 100 mg/100 mL. Your patient is 130 pounds and is receiving 20 mL/hour. Is the dose safe?

patient is receiving 20 mg/hour; yes, dose is safe
patient is receiving 20 mg/hour; yes, dose is not safe
patient is receiving 40 mg/hour; yes, dose is safe
patient is receiving 40 mg/hour; yes, dose is not safe

7. Your patient is to receive metoprolol tartrate (Lopressor) 25 mg/day PO. The pharmacist dispenses 50 mg scored tablets. How many tablets should your patient take each day?

1 tab
1/2 tab
2 tabs
2 1/2 tabs

8. A patient has an IV piggyback of ceftriaxone (Rocephin) 500 mg in 50 mL D5W to run over 20 minutes. The tubing has a drip factor of 10. How many drops per minute should be administered?

25 gtts/min
20 gtts/min
10 gtts/min
4 gtts/min

9. A home care patient must restrict fluid intake to 2 L every 24 hours. He has only household measuring cups. How many cups may he drink daily and not exceed the 2 L limit?

12 cups
12.3 or 12 and 1/3 cups
8 cups
8.3 or 8 and 1/3 cups

10. A patient has an IV piggyback of ceftriaxone (Rocephin) 500 mg in 50 mL D5W to run over 20 minutes. If you use an IV infusion controller, how many milliliters per hour will you set?

50 mL/hour
150 mL/hour
200 mL/hour
17 mL/hour

11. You are providing home care for a patient who needs 15 mL of magnesium hydroxide/aluminum hydroxide (Maalox) PO. She has only standard measuring spoons in the house. How do you instruct her to take her dose?

2 Tablespoon
1.5 Tablespoon
1 Tablespoon
2.5 Tablespoon

12. Your order reads penicillin 1.2 million units IM daily. You have penicillin 500,000 units/mL. How should you prepare the correct dose?

0.4 mL
2.4 mL
3 mL
4 mL

13. Your order reads labetalol 40 mg IV push every 10 minutes until blood pressure is lower than 140/90 mm Hg. You have labetalol 5 mg/mL available. How should you prepare the correct dose?

0.1 mL
4 mL
8 mL
8.5 mL

14. You have on hand ergocalciferol liquid 8000 units/2 mL. Your order reads ergocalciferol 225,000 units PO daily. How should you prepare the correct dose?

0.07 mL
14 mL
28 mL
56 mL

15. Your order reads ergocalciferol 225,000 units PO daily. You have on hand ergocalciferol in 50,000 unit tablets. How many do you administer?

4.5 tablets
3.5 tablets
2 tablets
0.5 tablet

16. Your order reads cortisone 15 mg PO every morning. You have on hand cortisone 10 mg tablets. How should you prepare the correct dose?

3 tablets
2 tablets
1.5 tablets
1 tablet

17. Your order reads ceftizoxime 1 g IV piggyback every 8 hours. The pharmacy supplies it in 100 mL D5W. You need to infuse it over 30 minutes. With a drop factor of 10, what drip rate will you set?

12 gtts/min
15 gtts/min
30 gtts/min
33 gtts/min

18. Your order reads Zosyn 4.5 g in 100 mL D5W IV over 1 hour. You have microdrip tubing. What drip rate will you set?

100 gtts/min
60 gtts/min
28 gtts/min
8 gtts/min

19. Your order reads levothyroxine 100 mg PO every morning. You have levothyroxine 0.05 mg tablets. How many tablets should you administer?

5 tablets
3 tablets
2 tablets
1.5 tablets

20. You have on hand morphine 500 mg in 500 mL normal saline. You need to administer morphine 80 mg/hour in a continuous IV infusion to a patient with terminal cancer pain. How many milliliters per hour will you set on the controller?

100 mL/hour
80 mL/hour
50 mL/hour
30 mL/hour

21. You have on hand enoxaparin (Lovenox) 30 mg/0.3 mL. You need to administer 1 mg/kg SC. Your patient weighs 200 pounds. How much will you draw into a syringe?

0.3 mL
0.9 mL
3 mL
6 mL

22. Amoxil (amoxicillin) suspension 180 mg PO bid is ordered for a patient who cannot swallow pills. It is supplied as 125 mg/5 mL. How many milliliters should you administer?

1.4 mL
3.5 mL
5 mL
7.2 mL

23. Heparin sodium, 1000 units/hour IV, is ordered for a patient with a blood clot in the leg. It is supplied as 50,000 units in 500 mL of dextrose and water. How many milliliters per hour should be set on the controller?

10 mL/hour
5 mL/hour
10.5 mL/hour
1 mL/hour

24. Diltiazem (Cardizem) 90 mg PO tid is ordered for a patient with hypertension. It is supplied in 60 mg scored tablets. How many tablets should you administer?

3.5 tablets
3 tablets
1.5 tablets
1 tablet

25. Atropine 0.6 mg IM is ordered preoperatively. It is supplied as 0.4 mg/mL. How many milliliters should you administer?

2.3 mL
2 mL
1.5 mL
0.7 mL

26. Morphine sulfate 2 mg IV push is ordered to relieve shortness of breath in a patient with chronic lung disease. It is supplied as gr 1/6 /mL. How many milliliters should you administer?

1 mL
0.2 mL
1.6 mL
0.03 mL

27. Each acetaminophen (Tylenol) #3 tablet has 325 mg of acetaminophen and 30 mg codeine. A patient is told to take 2 tablets PO every 4 hours for pain. The maximum safe dose of acetaminophen is 4 g/day. The safe dose of codeine varies with tolerance. Is the dose safe?

3.25 grams per day. Safe!
3.9 grams per day. Safe!
8.25 grams per day. Not safe!
8.9 grams per day. Not safe!

28. Levothyroxine (Synthroid) 150 mcg PO per day is ordered for a patient with hypothyroidism. It is supplied as 0.075 mg tablets. How many tablets should the patient take daily? A safe dose of Synthroid is 1.5 mcg/kg/day. The patient weighs 196 pounds. Is the dose safe?

2 tablets. The patient is receiving 1.5 mcg/kg. Safe!
1.5 tablets. The patient is receiving 1.5 mcg/kg. Safe!
2 tablets. The patient is receiving 1.7 mcg/kg. Not safe!
1.5 tablets. The patient is receiving 1.7 mcg/kg. Not safe!

29. A patient is receiving 250 mL normal saline IV over 4 hours, using tubing with a drip factor of 10 drops/mL. How many drops per minute should be delivered?

10 gtts/minute
18 gtts/minute
23 gtts/minute
31 gtts/minute

30. Cephazolin 1 g IV is ordered three times a day for a patient with pneumonia. It is supplied in 100 mL dextrose and water, to run over 20 minutes. How many milliliters per hour should you set the controller to deliver?

50 mL/hour
100 mL/hour
200 mL/hour
300 mL/hour

31. Your order reads ceftizoxime 1 g IV piggyback (IVPB) every 8 hours. The pharmacy supplies it in 100 mL D5W. You need to infuse it over 30 minutes. Using gravity drip tubing with a drop factor of 10, how fast will you run the piggyback?

23 gtts/min
33 gtts/min
38 gtts/min
42 gtts/min

32. You need to infuse 1000 mL of normal saline IV over 6 hours. How many milliliters per hour do you set on the IV infusion controller?

100 mL/hour
167 mL/hour
150 mL/hour
3 mL/hour

33. You have an order for fosphenytoin (Cerebyx) 100 phenytoin equivalents (PE) IVPB qid. It arrives in 50 mL of normal saline, with a note on the piggyback bag not to infuse faster than 150 PE/minute. How many milliliters per hour should you set on the controller?

4,500 mL/hour maximum rate
4,800 mL/hour maximum rate
5,000 mL/hour maximum rate
5,250 mL/hour maximum rate

34. You have 500 mL of lipids on a second IV infusion controller to piggyback into a primary hyperalimentation line. You want to run the infusion over 24 hours. At what rate should you run the lipids?

35 mL/hour
33 mL/hour
24 mL/hour
21 mL/hour

35. You have an order for 500 mg vancomycin IVPB every 6 hours for a patient who weighs 120 lbs. You know that you can safely administer up to 40 mg/kg/day. Is the order safe?

patient is receiving 36.7 mg/kg/day
patient is receiving 9.2 mg/kg/day
patient is receiving 40.0 mg/kg/day
patient is receiving 18.4 mg/kg/day

36. You have 350 mL packed red blood cells that you want to infuse IV over 2 hours. There is no controller available. Your blood tubing delivers 10 gtts/mL. How many drops per minute should you set?

3 gtts/minute
18 gtts/minute
29 gtts/minute
33 gtts/minute

37. You need to infuse corticotropin (Acthar) 25 U in 500 mL D5W IV over 8 hours. How many milliliters per hour do you infuse on a controller?

25 mL/hour
38 mL/hour
55 mL/hour
63 mL/hour

38. A patient is taking acetaminophen (Tylenol) 325 mg, 2 tablets PO every 6 hours. How many grams is the patient receiving in 24 hours?

2.6 g
2 g
1.6 g
1 g

39. You have an order for diphenhydramine hydrochloride (Benadryl) 40 mg IM now. You have on hand Benadryl 25 mg/mL. How many milliliters do you prepare?

2.5 mL
2 mL
1 mL
1.6 mL

40. You have digoxin (Lanoxin) 0.25 mg tablets, and you need to administer 0.375 mg PO. How many tablets should you administer?

0.7 tablet
1 tablet
1.5 tablets
2 tablets

Answers and Rationales

1. Answer: B. 2 mL

$10\, mg\times \frac{1\, mL}{5\, mg}= 2\, mL$

2. Answer: A. 4 mL

$40\, mg\times \frac{2\, mL}{20\, mg}= 4\, mL$

3. Answer: D. 1.5 mL

$15\, mg\times \frac{1\, gr}{60\, mg}\times \frac{1\, mL}{1/6\, gr}= 1.5\, mL$

4. Answer: C. 1.6 mL

$8\, mg\times \frac{1\, mL}{5\, mg}= 1.6\, mL$

5. Answer: B. 20 gtts/min

$\frac{20\, ml}{1\, hr}\times \frac{1\, hr}{60\, mins}\times \frac{60\, gtts}{mL}= 20\, gtts/min$

6. Answer: A. patient is receiving 20 mg/hour; yes, dose is safe

Because you have to compare a safe dose to the patient’s dose, you have to do two separate calculations:

$\frac{0.36\, mg}{kg}\times \frac{1\, kg}{2.2\, lbs}\times 130\, lbs= 21.3\, mg/hr\, is\, safe$

$\frac{20\, mL}{Hour}\times \frac{100\, mg}{100\, mL}= patient\, is\, receiving\, 20\, mg/hr;\, yes,\, dose\, is\, safe$

7. Answer: B. 1/2 tab

$25\, mg\times \frac{1\, tab}{50\, mg}= 1/2\, tab$

8. Answer: A. 25 gtts/min

$\frac{50\, mL}{20\, mins}\times \frac{10\, gtts}{mL}= 25\, gtts/min$

9. Answer: D. 8.3 or 8 and 1/3 cups

$2\, L\times \frac{100\, mL}{1\, L}\times \frac{1\, cup}{240\, mL}= 8.3\, or\, 8\, and\, 1/3\, cups$

10. Answer: B. 150 mL/hour

$\frac{50\, mL}{20\, mins}\times \frac{60\, mins}{1\, hr}= 150\, mL/hr$

11. Answer: C. 1 Tablespoon

$15\, mL\times \frac{1\, tbsp}{15\, mL}= 1\, tbsp$

12. Answer: B. 2.4 mL

$1,200,000\, units\times \frac{1\, mL}{500,000\, units}= 2.4\, mL$

13. Answer: C. 8 mL

$4\, mg\times \frac{1\, mL}{5\, mg}= 8\, mL$

14. Answer: D. 56 mL

$225,000\, units\times \frac{2\, mL}{8,000\, units}= 56\, mL$

15. Answer: A. 4.5 tablets

$225,000\, units\times \frac{1\, tablet}{50,000\, units}= 4.5\, tablets$

16. Answer: C. 1.5 tablets

$15\, mg\, units\times \frac{1\, tablet}{10\, mg}= 1.5\, tablets$

17. Answer: D. 33 gtts/min

$\frac{100\, mL}{30\, mins}\times \frac{10\, gtts}{mL}= 33\, gtts/min$

18. Answer: A. 100 gtts/min

$\frac{100\, mL}{1\, hr}\times \frac{1\, hr}{60\, mins}\times \frac{60\, gtts}{1\, mL}= 100\, gtts/min$

19. Answer: C. 2 tablets

$100\, mcg\times \frac{1\, mg}{1,000\, mcg}\times \frac{1\, tablet}{0.05\, mg}= 2\, tablets$

20. Answer: B. 80 mL/hour

$\frac{80\, mg}{hour}\times \frac{500\, mL}{500\, mg}= 80\, mL/hour$

21. Answer: B. 0.9 mL

$\frac{1\, mg}{kg}\times \frac{0.3\, mL}{30\, mg}\times 200\, lbs\times \frac{1\, kg}{2.2\, lbs}= 0.9\, mL$

22. Answer: D. 7.2 mL

$180\, mg\times \frac{5\, mL}{125\, mg}= 7.2\, mL$

23. Answer: A. 10 mL/hour

$\frac{1,000\, units}{1\, hour}\times \frac{500\, mL}{50,000\, units}= 10\, mL/hour$

24. Answer: C. 1.5 tablets

$90\, mg\times \frac{1\, tablet}{60\, mg}= 1.5\, tablets$

25. Answer: C. 1.5 mL

$0.6\, mg\times \frac{1\, mL}{0.4\, mg}= 1.5\, mL$

26. Answer: B. 0.2 mL

$2\, mg\times \frac{1\, gr}{60\, mg}\times \frac{1\, mL}{1/6\, gr}= 0.2\, mL$

27. Answer: B. 3.9 grams per day. Safe!

*Because the safe dose of codeine is variable and is determined by patient response, you only need to figure safe dose for the Tylenol for this problem.

$\frac{325\, mg}{tablet}\times \frac{2\, tablets}{dose}\times \frac{6\, doses}{day}\times \frac{1\, gram}{1,000\, mg}= 3.9\, grams\, per\, day$

*3.9 grams per day is less than the maximum safe dose of 4 grams, so it is safe.

28. Answer: C. 2 tablets. The patient is receiving 1.7 mcg/kg. Not safe!

$150\, mcg\times \frac{1\, mg}{1,000\, mcg}\times \frac{1\, tablet}{0.075\, mg}= 2\, tablets$

$\frac{150\, mcg}{196\, lbs}\times \frac{2.2\, lbs}{1\, kg}= the\, patient\, is\, receiving\, 1.7\, mcg/kg$

*Not safe, the dose of 1.7 mg/kg is greater than 1.5 mg/kg, so the dose is too high

29. Answer: A. 10 gtts/minute

$\frac{250\, mL}{4\, hrs}\times \frac{1\, hr}{60\, mins}\times \frac{10\, gtts}{mL}= 10\, gtts/min$

30. Answer: D. 300 mL/hour

$\frac{100\, mL}{20\, mins}\times \frac{1\, hr}{60\, mins}= 300\, mL/hour$

31. Answer: B. 33 gtts/min

$\frac{100\, mL}{30\, mins}\times \frac{60\, min}{hour}= 33\, gtts/min$

32. Answer: B. 167 mL/hour

$\frac{1000\, mL}{6\, hrs}= 167\, mL/hour$

33. Answer: A. 4,500 mL/hour maximum rate

$\frac{150\, PE}{minute}\times \frac{50\, mL}{100\, PE}\times \frac{60\, minutes}{1\, hr}= 4,500\, mL/hour$

*Although 4500 mL/hour is the maximum rate, there is no reason to run it that fast; doing so could damage the vein. Most piggybacks are infused over 20 to 30 minutes, or according to hospital policy. 50 mL infused over 30 minutes would be set at 100 mL/hour, which is well under the maximum rate.

34. Answer: D. 21 mL/hour

$\frac{500\, mL}{24\, hrs}= 21\, mL/hour$

35. Answer: A. patient is receiving 36.7 mg/kg/day

$\frac{500\, mg}{120\, lbs}\times \frac{4\, doses}{day}\times \frac{2.2\, lbs}{1\, kg}= patient\, is\, receiving\, 36.7\, mg/kg/day$

*36.7 mg/kg is less than the safe dose of 40 mg/kg, so it is safe.

36. Answer: C. 29 gtts/minute

$\frac{350\, mL}{2\, hrs}\times \frac{1\, hr}{60\, mins}\times \frac{10\, gtts}{1\, mL}= 29\, gtts/minute$

37. Answer: D. 63 mL/hour

$\frac{500\, mL}{8\, hrs}= 63\, mL/hour$

38. Answer: A. 2.6 g

$\frac{325\, mg}{tablet}\times \frac{2\, tablets}{dose}\times \frac{4\, doses}{day}\times \frac{1\, g}{1,000\, mg}= 2.6\, g$

39. Answer: D. 1.6 mL

$40\, mg\times \frac{1\, mL}{25\, mg}= 1.6\, mL$

40. Answer: C. 1.5 tablets

$0.375\, mg\times \frac{1\, tablet}{0.25\, mg}= 1.5\, tablets$