Nursing
DOSAGE CALCULATIONS PRACTICE TEST
Doctor’s Orders: You Have: You Give:
1. Bactrim 1.5 G 1 tab = 500 mg ____________
2. Morphine gr ¼ gr 1/8 per ml ____________
3. Atropine gr 1/150 gr 1/100 per ml ____________
4. Levoxyl 0.3 mg 1 tab = 300 mcg ____________
5. KCl 30 meq 20 meq/30 ml ____________
6. Valium 2.5 mg 1 tab = 5 mg ____________
7. PENN V – K 250,000 U 2 ml = 1 million U ____________
8. Demerol 35 mg 1 ml = 100 mg ____________
9. Tetracycline 500mg 1.5 ml = 1 gram ____________
10. Bactrim 1 Gm p.o. 200 mg/5ml ____________
11. Benadryl gr i gr 1/2 in 2ml ____________
12. Ancef 1000 mg 1 cap = 250 mg ____________
13. Codeine gr 1/3 1 tab = gr ¼ ____________
14. NaHCO3 1.7 Gm 1 tab = 600mg ____________
15. Robitussin 20 ml is ordered. Robitussin comes in 4 ounce bottles. How many doses are in each bottle. __________________________
16.Garamycin 20 mg is ordered. The drug is supplied in a 2 ml vial containing 40 mg per ml. How many ml’s will you give? ____________________
17.You are to administer potassium chloride 36 meq. The label on the vial reads KCL 10 ml = 20 meq. How much will you give? ______________________-
18.The vial of powdered material is labeled Keflin 1 Gram. The directions say to add 2.5 ml of sterile saline. The solution will then equal 3 mls. You are to administer Keflin 500 mg IM. How much will you give:___________________________
19.Patient is to receive 1000 ml. D5W over 8 hours. How many gtts/minute?__________
Gtt factor = 20
20.Patient is to receive 75 ml. D5LR per hour. How many ml will he receive in 24
hours?_____________________
Gtt factor = 60
21.Patient is to receive 2500 ml over 24 hours. How many gtts/minute?___________
Gtt factor = 20
22. Patient is to receive 250 ml over 3 hours. How many gtts/minute?___________
Gtt factor = 15
23.Patient is to receive 1000 ml NS with 60 Meq KCL (50ml), 50ml NaHCO3, and 20 ml MVI over 10 hours. How many gtts/minute?____________________________
gtt factor = 60.
24. Patient is receiving an IV at 15 gtt/minute. At 8PM, when you get report, there are 720 ml to count. At what time should it be completed? _________
Gtt factor = 10
25. Your patient has an IV infusing at 25 gtt/minute. How many ml will he receive per hour?________________
Gtt factor 20
Answers to Practice Calculation Quiz:
- 3 tabs
- 2 ml
- 2/3 ml
- 1 tabs
- 45 ml
- 0.5 tabs
- 0.5 ml
- 0.35 ml
- 0.75 ml
- 25 ml
- 4 ml
- 4 caps
- 1 1/3 tabs
- 2.83
- 6
- 0.5 ml
- 18 ml
- 1.5 ml
- 41-42
- 1800
- 34-35
- 20-21
- 112
- 4am
- 75 ml
MORE problems for practice:
How to do the problems
gr 1 means 1 grain; 1 grain is equal to 60 milligrams
gr ss mean 1/2 of a grain
d/b means divided by in the problems below.
1 ounce is equal to 30 ml
The formula for IV calculations is:
Drops per minute = (volume times the drop factor) divided by time in minutes.
To calculate drug dosage:
Desired amount divided by the amount on hand times what the amount you have on hand is in.
1) (1.5G divided by (d/b) 500mg) x 1 tablet (have to convert grams to milligrams)
1500/500 x 1 = ______ tab(s)
3 x 1 =
3 tablets to give the person
2) gr 1/4 d/b gr 1/8 x 1ml. = _________ml.
(1/4 d/b 1/8) = 1/4 x 8/1 = 8/4 = 2 Then 2 x 1ml. = 2ml.
3) gr 1/150 d/b gr 1/100 x 1ml. = _______ml.
1/150 d/b 1/100 = 1/150 x 100/1 = 100/150 = 2/3 Then 2/3 x 1ml. = 2/3 ml. .
4) 0.3 mg d/b 300 mcg x 1 tablet = ________tab(s)
0.3 mg = 300mcg So….. 300mcg d/b 300 mcg = 1;
Then 1 x 1 tablet = 1 tablet to give the patient
5) 30 meq d/b 20 meq x 30ml. = _______ ml.
30 / 20 = 1 ½
Then 1.5 x 30 = 45 ml. to give the person
6) 2.5 mg d/b 5 mg x 1 tablet = _______ tab(s)
2.5 / 5 = 0.5
0.5 x 1 tablet = 0.5 tab to give the patient or ½ tablet to the patient
7) 250,000 units d/b 1 million units x 2ml. = _______ml.
Convert first, then divide
250,000 / 1,000,000 = ¼
So ¼ x 2 ml. = 2/4 which = ½
So give patient 0.5 ml. or ½ ml.
8) 35 mg d/b 100 mg x 1ml. = ______ ml.
35/100 = 0.35
So 0.35 x 1ml. = 0.35 ml. to give the patient
9) 500 mg d/b 1 gram x 1.5ml. = _______ml.
Convert then divide
500mg/1000mg = 0.5
so 0.5 x 1.5 = 0.75ml. to give the patient
10) 1 gram d/b 200 mg x 5 ml. = _______ml.
Convert then divide
1000mg / 200 mg = 5
so 5 x 5ml. = 25 ml. to give the patient
11) griss d/b 0.12 grams x 2 ml. = _______ml.
Convert first
1 ½ grains = ______ mg; 0.12 grams = 120 mg
There are 60 mg in 1 grain so 1.5 x 60 = 90 mg
So…
90/120 x 2ml.
0.75 x 2 ml. = 1.5 ml. to give the patient
12) 1000 mg d/b 250mg x 1 capsule = ______ caps
1000/250 x 1 =
4 x 1 = 4 caps to give the patient.
13) 1/3 gr d/b 1/4 gr x 1 tab = _______tab(s)
Convert then divide
1 grain is 60 mg so…
1/3 of 60 or 1/3 x 60 = 20 mg
Then 1/4 of 60 or 1/4 x 60 = 15 mg
Then 20/15 x 1 tablet = ____
1.3 x 1 = 1 1/3 tablets
14) 1.7 grams d/b 10 grains x 1 tablet =______tablet(s)
Convert first
If there are 60 mg in 1 grain then there are
60 x 10 in 10 grains or
600 mgs in 10 grains.
1.7 grams = 1700 mgs so
1700mg/600mg x 1 tablet = _______ tablet(s)
2.83 x 1 tab = 2.83 tabs.
In real life you’d need to call the doctor and get him to order it in liquid or
increase the dose or something because you can’t divide a tablet into 0.83!
This is strictly a math problem. For drug dosage test, do not round unless
instructed to do so.
15) 20ml. each dose 4 ounces in 1 bottle. How many doses are in each bottle?
1 ounce = 30 ml. s so 4 ounces = how many ml. = 4 x 30 = 120 ml. s
120 / 20 = 6; so there are 6 doses in each bottle
16) 20 mg / 40 mg x 1 ml
20/40 = ½
½ x 1 ml = ½ ml or 0.5 ml to give the patient
(you had a 2 ml vial with 40mg/ml) (80 mg total in the vial)
17) 36meq/20meq x 10 ml = ______ mls
1.8 x 10 mls = 18mls to give the patient
18) 500mg / 1 gram x 3 mls = _______ mls
Convert first
500mg/ 1000mg x 3 ml = ______
½ x 3 ml = 1.5 mls
Remember that you will administer the solution, not the solute or powder in the
vial. Have to mix it first; so use the total volume of the solution (powder & saline).
19) 1000 ml. over 8 hours. How many gtts per minute do you infuse.
I like small numbers, so I find out how many ml. s in 1 hour.
1000ml. / 8 hours = 125 ml. / hour. ( 125 ml. in 1 hour)
Our drop factor is 20, so now plug into the equation:
Gtts/minute = volume x gtt factor
time in minutes
X = 125 x 20
- (since there are 60 minutes in 1 hour)
X = 2500/60
X = 41.666 or 42 gtts per minute
Always round drops to the nearest drop.
You could reduce first then multiply: 125 x 1 = 41.666 or 42 gtts per minute.
20) 75ml. /hour. How many in 24 hours. 75 x 24 = 1800 ml. or mls in 24 hours.
75ml = xml
1 hr 24hr x = 75 x 24
x = 1800 mls.
21) 2500ml over 24 hours Gtts per minute? Gtt factor = 20
2500ml /24hours = 104.2 ml in one hour
Gtts per minute = 104.2 x 20
60 minutes
x = 2084/60 or 34.7 or 35 gtts per minute
could reduce and say (104.2 x 1) divided by 3 = 34.7 or 35 gtts per minute
22) 250 ml over 3 hours Gtts per minute?
250/3 = 83.3 ml in 1 hour
gtts per minute = 83.3 x 15 (the drop factor given in the problem)
60
x = 1249.5/60 = 20.8
x = 20.8 or 21 gtts per minute
could reduce and say (83.3 x 1) divided by 4 = 20.8 or 21 gtts per minute
23) Need to add all of the volumes injected into the IV bag to get the total volume in the bag.
1000 +50 +50 + 20 = 1120 mls in the bag total. Need to know this first.
Needs to infuse over 10 hours so
1120/10 = 112 mls per hour the patient needs to receive.
Gtt factor – 60 in this problem.
Gtts/minute = 112 x 60
60
The 60s cancel each other out and the answer is 112 gtts per minute. That’s what
is great about a drop factor of 60 in these problems.
24) getting 15 gtts per minute, since the drop factor is 10; 15/10 = 1.5 ml per minute
1.5 x 60 minutes = 90 ml /hour
If 720 to count in the bag at 8PM when you get report:
720 ml /90ml in 1 hour = 8 hours left to go
When will it be completed?
If 8 hours are left and it is 8PM, then should be in at 0400 or 4AM.
25) 25 gtt/minute infusing. How many ml will he get per hour if drop factor is 20. Just
fill in the numbers into the equation. You know he is getting 25 gtts in one minute.
A drop factor of 20 means that 20 gtts = 1 ml
So how many ml is 25 gtts? 25/20 = 1.25
So the patient is receiving 1.25ml in one minute.
So in 60 minutes or 1 hour, he receives 1.25 x 60 or 75 ml or mls
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