# Med Calc Calculations - Practice Questions

```College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
Calculations - Practice Questions
Reminders:
 DOSAGES: all fractions MUST be converted to decimals.
 DRIP RATES: for rates gtts/min convert all fractions to the nearest whole number (example:
75.4 = 75; 43.5 = 44). You cannot count a portion of a drop.
 PUMP RATES: for rates in mL/hr, round according to how many digits the IV pump can
accommodate. With Baxter pumps you can input up to 3 digits (example: 999 mL/hour; 97.8
mL/hr; 9.85 mL/hr.
 You MUST give the units of measure in your answers (example: “mg” or “mL/hr”).
 If there is a drop factor in the question, you are being asked to calculate gravity drip rate.
Drip Rates
1. Calculate the drops per minute (gtts/min) using an administration set with drop factor of 10
drops/ml (macro drip):
a. IV of D1/2NS at 150 ml/hr
b. IV of D5W at 125 ml/hr
c. IV of D1/2NS with 20 mEq of KCl at 100 ml/hr
d. IV of NS at 75 ml/hr
e. IV of 1/3 Dextrose, 2/3 Saline at 50 ml/hr
2. Calculate the drops per minute (gtts/min) for the each of the above using an administration
set with a drop factor of 15 drops/ml (macro drip).
3. Calculate the drops per minute (gtts/min) for the each of the above using an administration
set with a drop factor of 60 drops/ml (micro drip):
4. The physician's order reads: 1 unit packed red blood cells over 2 hours
The blood administration set delivers 10 drops/ml. The blood bag contains 350 ml of red cell
concentrate.
What should the flow rate (drops/min) be set at?
5. The physician's order reads: 1 unit 25% albumin (100 ml) over 1 hour
The albumin administration set delivers 10 drops/ml.
What should the flow rate be set at?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
IV Medications: Dosages, Concentrations, Pump Rates and Completion Times
Penicillin G 1,000,000 units IV q8h
Reconstitute by adding 9.5 ml of sterile water to vial.
Final concentration = 100,000 units/ml.
How many ml are required for one dose?
Clindamycin 300 mg IV q6h
Add 4.8 ml of sterile water to the vial for a final concentration of
150mg/ml.
How many ml are required for one dose?
Carbenicillin 750 mg IV q6h
Add 9.5 ml of sterile water to vial
Final concentration = 500mg/ml.
How many ml are required for one dose?
Erythromycin 250 mg IV q8h
1g vial: Add 19.2 ml of sterile water to vial
Final volume = 20 ml.
What is the final concentration of the vial?
How many ml are required for one dose?
Vancomycin 250 mg IV q12h
Add 10 ml of sterile water to vial
Final concentration = 50 mg/mL.
How many ml are required for one dose?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
Ativan 1 mg IV x 1 STAT
Final concentration = 4 mg/ ml
How many ml are required for one dose?
Aminophylline 0.25 g IV over 6 hours.
The label of the medication reads:
500 mg per 20 mL
What is the final concentration?
How many ml are required for one dose?
Morphine sulfate 2.5 mg IV STAT
The label reads: 10 mg/ ml
How many ml are required for one dose?
Gentamycin 80 mg IV q8h
The label reads: 40 mg/ ml
How many ml are required for one dose?
Dilaudid 2 mg IV q6h prn
The label reads: 4 mg / ml
How many ml are required for one dose?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
IV D5W at 100 mL/hr
Ranitidine 150 mg IV
The vial = 50 mg/2 mL
Dilute in 50 mL of IV solution
What is the final concentration of this medication in the vial?
How many ml of the drug will you administer?
IV D51/2NS at 75 ml/hr
Mefoxin 1000 mg IV
Vial of Mefoxin = 1g
Dilute in 20-150 ml of IV solution
What is the final concentration of this medication in the vial?
How many ml of the drug will you administer?
IV D5W at 50 ml/hr
Cefuroxime 750 mg IV
Final concentration = 100 mg/ml.
Dilute in 100 ml of IV solution
How many ml of the drug will you administer?
19. Dr. Evermore has ordered an IV Bolus of NS 1 L.
What will the IV rate be set at in order to infuse the bolus over 2 hours via an IV
pump?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
20. Nurse Pam is administering IV Cloxacillin via an intermittent infusion lock. She dilutes the
medication in 50 mL of IV fluid. The monograph gives a range of 30-60 min for administration
of the medication. When using a IV pump:
At what rate should Pam set the pump if administering the
medication over 30min?
At what rate should Pam set the pump if administering the
medication over 60min?
21. You have a patient with a 500 ml IV of 0.9%NS running at 75 ml/hr. At 0900 hrs you do
your hourly check. 150 ml have been absorbed. At what time will the IV fluid be completely
absorbed?
22. If you have an IV bag of D5W (1000 ml) running at 125 ml/hr, how many hours will it take
to infuse?
23. At 2200 hrs you do a round to check on your patients. Mr. Smith’s IV is a 1000 ml bag of
0.9%NS infusing at 50 ml/hr. When you check it, 300 ml have been infused. At what time will
the IV fluid be completely absorbed?
24. Your patient is receiving an IV of D5W with 40 mEq KCL per litre. The doctors order says
to run the IV infusion at 150 ml/hr. How much KCL is your patient receiving each hour?
25. Your surgery patient has an IV established prior to going to the OR. An IV of D5 &frac12; NS
started. The patient is supposed to get 500 ml of fluid before going for surgery in 3 hours.
What is the infusion rate in ml per hour?
26. You are looking after a laboring patient who is receiving an IV. The physician wants 1000 ml
of 0.9%NS to infuse in 5 hours.
What is the infusion rate in ml per hour?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
27. The laboring patient you are looking after requires Fentanyl for analgesia. Fentanyl is
supplied by pharmacy in a 200 mcg/ml vial. The order is to give 50 mcg IV push now and then
50 mcg IV push in 10 minutes.
How many ml are you going to draw up in the syringe?
If you draw up 0.5 ml of Fentanyl in a syringe, what dose of the medication are you
28. Methylprednisone is supplied in a 125 mg vial. The monograph reads: Add 1.8 mL of sterile
water for a total volume of 2 mL.
(a) Once reconstituted, what is the final concentration in the vial?
(b) How many mL would be required for an 85 mg dose?
(c) You further dilute the medication in a 50 mL mini-bag.
The monograph states the medication rate of administration is 125 mL/hr. How long
will it take for the medication to infuse?
29. The physician order reads: Gentamicin 140 mg IV bid.
The label on the 2 mL vial supplied by the pharmacy reads gentamicin 40 mg/mL.
(a) How many mL are required for one dose?
(b) The patient’s dose is increased and he now receives 5 mL of the same concentration
of Gentamicin. How many milligrams of drug will he now be given in one dose?
(c) You further dilute the 3.5 mL dose in a 100 mL mini-bag and the patient’s IV rate is
125 mL/hr.
How long will it take for the medication to infuse?
30. Your patient has a 1 litre bag of NS infusing at 60 mL/hr. When doing rounds at 0800
you check the infusion and note that it is running on time. 270 mL have been absorbed.
At what time should the bag be completely infused?
31. Your patient has a 500 mL bag of NS infusing at 25 mL / hr. When doing rounds at 1000
you check the infusion and note that it is running on time. 150 mL have been absorbed.
At what time should the bag be completely infused?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
32. The physician order reads: Give 3480 ml IV Normal Saline fluid replacement over 24 hours.
Calculate the hourly rate.
33. The physician’s order reads: Lactated Ringer’s IV @ 150 mL / hr.
Calculate the total volume of IV fluid your client will receive in a 24 hour period at
this rate of infusion.
34. The physician’s order reads: Heparin 4000 units IV STAT. You have a 10 ml Heparin vial
labelled 1000 units/ml.
How many mL would be required to give the ordered dose?
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
1. Calculate the drops per minute (gtts/min) using an administration set with drop factor of 10
drops/ml (macro drip):
a. IV of D1/2NS at 150 ml/hr
25gtts/min
b. IV of D5W at 125 ml/hr
20.8=21gtts/min
c. IV of D1/2NS with 20 mEq of KCl at 100 ml/hr
16.67=17gtts/min
d. IV of NS at 75 ml/hr
12.5=13gtts/min
e. IV of 1/3 Dextrose, 2/3 Saline at 50 ml/hr
8.33=8gtts/min
2. Calculate the drops per minute (gtts/min) for the each of the above using an administration
set with a drop factor of 15 drops/ml (macro drip):
a. 37.5=38gtts/min b. 31.2=31gtts/min
c. 24.9=25gtts/min d. 18.75=19gtts/min
e. 12.5=13gtts/min
3. Calculate the drops per minute (gtts/min) for the each of the above using an administration
set with a drop factor of 60 drops/ml (micro drip):
a. 150gtts/min b. 125gtts/min
c. 100gtts/min d. 75gtts/min
e. 50gtts/min
1 unit packed cells over 2 hours
The blood administration set delivers 10 drops/ml. The blood bag contains
350 ml of red cell concentrate.
What should the flow rate (drops/min) be set at?
29.17=29gtts/min
1 unit 25% albumin (100 ml) over 1 hour
The albumin administration set delivers 10 drops/ml.
What should the flow rate (drops/min) be set at? 16.6 gtts/min = 17 gtts/min
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
Penicillin G 1,000,000 units IV q8h
Reconstitute by adding 9.5 ml of sterile water to vial.
Final concentration = 100,000 units/ml.
How many ml are required for one dose?
1 000 000u/100 000u X 1ml =10ml
Clindamycin 300 mg IV q6h
Add 4.8 ml of sterile water to the vial for a final concentration of
150mg/ml.
How many ml are required for one dose?
300mg/150mg X 1ml =2ml
Carbenicillin 750 mg IV q6h
Add 9.5 ml of sterile water to vial
Final concentration = 500mg/ml.
How many ml are required for one dose?
750mg/500mg X 1ml = 1.5ml
Erythromycin 250 mg IV q8h
1g vial: Add 19.2 ml of sterile water to vial
Final volume = 20 ml.
What is the final concentration?
1000mg/20ml = 50mg/ml
How many mLs are required for one dose?
250mg/50mg X 1ml =5ml
Vancomycin 250 mg IV q12h
Add 10 ml of sterile water to vial
Final concentration = 50 mg/mL.
How many mLs are required for one dose?
250mg/50mg X 1ml = 5ml
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
Ativan 1mg IV x 1 STAT
Final concentration = 4 mg/ ml
How many ml are required for one dose?
1mg/4mg X 1ml = 0.25ml
Aminophylline 0.25g IV over 6 hours.
The label of the medication reads:
500 mg per 20mL
What is the final concentration?
500mg/20ml = 25mg/ml
How many ml are required for one dose?
250mg/25mg X 1ml = 10ml
Morphine sulfate 2.5 mg IV STAT
The label reads: 10 mg/ ml
How many ml are required for one dose?
2.5mg/10mg X 1ml = 0.25ml
Gentamycin 80mg IV q8h
The label reads: 40 mg/ ml
How many ml are required for one dose?
80mg/40mg X 1ml = 2ml
Dilaudid 2 mg IV q6h (prn)
The label reads: 4 mg / ml
How many ml are required for one dose?
2mg/4mg X 1ml = 0.5ml
IV D5W at 100 ml/hr
Ranitidine 150 mg IV
Dilute in 50 ml of IV solution
What is the final concentration of this medication?
50mg/2ml = 25mg/ml
How many ml of the drug will you administer?
150mg/25mg X 1ml = 6ml
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
IV 5D /2NS at 75 ml/hr
Mefoxin 1000 mg IV
the vial of Mefoxin reads- 1g
dilute in 20-150 ml of IV solution
What is the final concentration of this medication?
1000mg/10ml = 100mg/ml
How many ml of the drug will you administer?
1000mg/100mg X 1ml = 10ml
IV D5W at 50 ml/hr
Cefuroxime 750 mg IV
Final concentration of 100 mg/ml.
Dilute in 100 ml of IV solution
How many ml of the drug will you administer?
750mg/100 mg X 1ml = 7.5ml
19. Dr. Ivmoore has ordered an IV Bolus of NS 1L. What will the IV rate be
set at in order to infuse the bolus over 2hrs via an IV pump.
1000ml/2hrs = 500ml/hr
20. Nurse Pam is administering IV Cloxacillin via an intermittent infusion lock.
She dilutes the medication in 50 mls of IV fluid. The monograph gives a
range of 30-60 min for administration of the medication.
When using a volumetric pump :
At what rate should Pam set the pump if administering the
medication over 30min?
50ml/0.5hr = 100ml/hr
At what rate should Pam set the pump if administering the
medication over 60min?
50ml/1hr = 50ml/hr
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
21. You have a patient with a 500 ml IV of 0.9%NS running at 75 ml/hr. At 0900
hrs you do your hourly check. 150 ml have been absorbed. At what time
will the IV fluid be completely absorbed?
500 ml – 150 ml= 350 ml fluid remaining
350 &divide; 75=4.67 (It will take 4.67 hours for the infusion to be
completed)
0900+0400=1300
0.67 &times; 60 (to find out the minutes)=40.2, rounded off equals 40
minutes
1300+40=1340 hrs
The IV fluid will be completely absorbed at 1340 hrs.
22. If you have an IV bag of D5W (1000 ml) running at 125 ml/hr, how many
hours will it take to infuse?
1000 mls &divide; 125 mls/hr= 8 hours
23. At 2200 hrs you do a round to check on your patients. Mr. Smith’s IV is a
1000ml bag of 0.9%NS infusing at 50 ml/hr. When you check it, 300 ml have
been infused. At what time will the IV fluid be completely absorbed?
1000 ml-300 ml= 700 ml
700 &divide; 50=14 hours
2200 hrs + 14hrs= 1200hrs
24. Your patient is receiving an IV of D5W with 40 mEq KCL per litre. The
doctors order says to run the IV infusion at 150 ml/hr. How much KCL is
40 mEq = x
1000 ml 150 ml
40mEq &times;150ml =6 mEq
1000
25. Your surgery patient has an IV established prior to going to the OR. An IV of
D5 &frac12; NS started. The patient is supposed to get 500 ml of fluid before
going for surgery in 3 hours.
What is the infusion rate in ml per hour?
500 ml &divide; 3 hrs = 166.67, rounded off is 167 ml/hr.
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
26. You are looking after a laboring patient who is receiving an IV. The
physician wants 1000 ml of 0.9%NS to infuse in 5 hours.
What is the infusion rate in ml per hour?
1000 ml &divide; 5hrs = 200 ml/hr
27. The laboring patient you are looking after requires Fentanyl for analgesia.
Fentanyl is supplied by pharmacy in a 200mcg/ml vial.
The order is to give 50 mcg IV push now and then 50 mcg IV push in 10 minutes.
a. How many mLs are you going to draw up in the syringe?
1ml =
200mcg
x
50mcg
1ml x 50mcg
200mcg
0.25 ml is needed
b. If you draw up 0.5 ml of Fentanyl in a syringe, what dose of the
200 mcg = x
1ml
0.5ml
200mcg x 0.5ml
1ml
100mcg
28. Methylprednisone is supplied in a 125 mg vial. The monograph reads:
Add 1.8 mL of sterile water for a total volume of 2 mL.
Once reconstituted, what is the final concentration in the vial? 125mg/ 2ml = 62.5mg/ml
How many mL would be required for a 85 mg dose? 85/62.5 mg X 1ml = 1.36ml
You further dilute the medication in a 50 mL minibag.
The monograph states the medication rate of administration is 125 mL/hr. How long will
it take for the medication to infuse?
125 ml = 51.36ml
60 min.
X
X= 24.7min.
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
29. The physician order reads: Gentamicin 140 mg IV bid.
The label on the 2 mL vial supplied by the pharmacy reads gentamicin 40 mg/mL.
How many mL are required for one dose? 140mg/40mg x 1ml = 3.5ml
The patient’s dose is increased and he now receives 5 mL of the same concentration of
Gentamicin. How many milligrams of drug will he now be given in one dose?
5ml x 40mg/ml = 200mg
You further dilute the 3.5 ml in a 100mL minibag and the patient’s IV rate is 125 mL/hr.
How long will it take for the medication to infuse?
125ml = 103.5ml
X= 49.7 min.
60 min.
x min.
30. Your patient has a 1 litre bag of NS infusing at 60 mL / hr. When doing rounds at 0800
you check the infusion and note that it is running on time. 270 mL have been absorbed.
At what time should the bag be completely infused?
1000ml – 270 ml = 730 ml remaining in the bag
730ml/60ml/hr = 12.17 hrs = 12.2 hours = 12hr12min.
0800hrs + 12hr12min. = 2012 hrs.
31. Your patient has a 500 mL bag of NS infusing at 25 mL / hr. When doing rounds at 1000
you check the infusion and note that it is running on time. 150 mL have been absorbed.
At what time should the bag be completely infused?
500ml – 150 ml = 350ml remaining in the bag
350ml/25ml/hr = 14 hours
1000hrs + 1400hours = 2400 hrs
32. The physician order reads: Give 3480 ml IV Normal Saline fluid replacement over 24 hours.
(a) Calculate the hourly rate.
3480 ml/ 24 hr. = 145ml/hr
33. The physician’s order reads: Lactated Ringer’s IV @ 150 mL / hr.
Calculate the total volume of IV fluid your client will receive in a 24 hour period at this
rate of
infusion. 150ml/hr x 24 hr = 3600 ml
College of Nursing, University of Manitoba
NURS 3530: Nursing Skills 3
34. The physician’s order reads: Heparin 4000 units IV STAT. You have a 10 ml Heparin vial
labelled 1000 units/ml.
How many mL would be required to give the ordered dose?
4000units/1000units x 1mL = 4 ml
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