Dosage
Calculation
Review
General Rules of Thumb
Identify what the question is asking for.
Discard any unnecessary information.
Never round until the absolute end of your calculations.
Make sure you round as the question requests.
Review your answer and evaluate if it sounds appropriate.
If it seems odd, repeat your calculations.
Remember, pediatric dosages are usually very small!
#1
A pediatrician has ordered cefazolin 150 mg/kg/day IV divided q8 hours for a child who
weighs 25 lbs.
How many kilograms does the child weigh? (Round to the nearest tenths
place) NUMERIC VALUE ONLY
11.4 kg=25 lbs /2.2
#2
A newborn is ordered to receive a NS fluid bolus of over 1 hour. The newborn weighs 6
lbs. 15 oz.
What does the newborn weigh in kg? (Round to the nearest tenth) NUMERIC VALUE
ONLY
16 oz = 1 lbs,
15/16=0.9375 lbs
6+0.9375=6.9375
6.9375/2.2=3.2 kg
#3
How many mLs are in 20 ounces?
30 mls = 1 ounce
20*30=600 ml
#4
A nurse is preparing to administer ibuprofen 10mg/kg every 6 hours prn for temperatures
above 38.0 C (100.5 F) to an infant that weighs 22.8 lbs. The infant has a temperate of
38.4 C (102.1 F). Ibuprofen liquid is supplied 100mg/5mL.
How many mL should the nurse administer to the infant per dose? (Round to the nearest
tenth's place.) NUMERIC VALUE ONLY
1.) 22.8/2.2=10.3636364
2.) 10.36*10=103.36 mg
3.) 103.36/100*5=5.2
#5
The recommended dosage of Rocephin is 50 to 100 mg/kg/day divided into two equal
doses. The physician has ordered Rocephin 150 mg IM every 12 hours for a child who
weighs 3000 g. The Rocephin vial contains 1g of medication that must be reconstituted
with 3.6 mL of diluent to yield 1 g/4 mL.
What is the recommended minimum amount of milligrams that the child should
receive per dose? NUMERIC VALUE ONLY
1.) 3000 g = 3 kg
2.) 50 mg * 3 kg = 150 mg per day
3.) 150 mg / 2 = 75 mg
#6
A pediatrician has ordered cefazolin 150 mg/kg/day IV divided q8 hours for a child who
weighs 25 lbs.
What dose will the child receive at 4pm? (Round to the nearest whole number) NUMERIC
VALUE ONLY
1.) 25 lbs /2.2= 11.36 kg
2.) 11.36 * 150 mg = 1704.5454
3.) 1704.5454/3= 568
#7
A pediatrician has ordered cefazolin 150 mg/kg/day p.o. divided q.8h for a child who
weighs 25 lbs.
How many milligrams should the child receive per day? (Round to the nearest whole
number) NUMERIC VALUE ONLY
1.) 25 lbs/2.2=11.4
2.) 150 mg *11.36=1705
#8
There is an order is to infuse 500mL of D5 1/2NS over 4 hours to a 16-year-old client
while in a procedure.
How many milliliters per hour should the IV pump be programmed for? NUMERIC VALUE
ONLY
500 ml/4=125
#9
The nurse is caring for a client who has been ordered acetaminophen 250mg POq 4-6
hours for pain. The nurse has available acetaminophen 160mg/5mL.
How many milliliters would be needed to administer 250mg? (Round to the nearest
tenth's place) NUMERICAL VALUE ONLY
(250/160)*5=7.8
#10
An infant weighing 7 lbs 5 ounces is to receive 400 ml of blood over 4 hours.
Using a microdrip (55 gtt/ml), how many drops per minute are needed? NUMERIC
VALUE ONLY
(55 gtt *400 ml)/240 minutes=92 gtt
#11
The doctor ordered 2000 ml of lipids to be infused from 2100 to 0900.
What rate will you set the IV to run at to achieve this? (NUMERIC VALUE ONLY)
1. 12 hrs
2. 2,000 ml /12 hrs = 167 ml
#12
A doctor orders 300 mg of zithromax once a day for a child that weighs 72lbs. The safe
dose range for this medication is 10-12 mg/kg/day.
What is the recommended max safe and therapeutic single dose for this child in mg?
(Round to the nearest whole number) NUMERIC VAULE ONLY
1.) 72/2.2= 32.73
2.) 12*32.73= 393
#13
An order is placed for a 7-year-old to receive Amoxicillin 300mg. The recommended max
safe dose of Amoxicillin for a child is 25-45mg/kg/per day divided in doses every 12
hours. The child’s weight is 40 pounds.
Amoxicillin is supplied 400mg/5ml. How many milliliters will the nurse administer per
dose? (Round to the nearest tenths place) NUMERIC VALUE ONLY
(300/400)*5=3.8
#14
The recommended dosage of Rocephin is 50 to 100 mg/kg/day divided into two equal
doses. The physician has ordered Rocephin 50 mg IM every 12 hours for a child who
weighs 3000 g. The Rocephin vial contains 1g of medication that must be reconstituted
with 3.6 mL of diluent to yield 1 g/4 mL.
Is the order within the safe dose range for this child? Write YES or NO
1. Min: 3kg*50=150/2=75
2. Max: 3kg*100=300/2=150
No, it’s too low. 50 mg is not safe.
#15
A doctor orders 350 mg of zithromax once a day for a child that weighs 72lbs. The safe
dose range for this medication is 10-12 mg/kg/day.
Is this order within the safe dose range for this child? Write YES or NO
1. 72lbs/2.2=32.73
2. Min: 32.73*10=327.3
3. Max: 32.73*12=392.73
4. Yes, 350 is right in between the min and max.
#16
A pediatrician has ordered ampicillin 100 mg/kg/day p.o. divided q.6h for a child who
weighs 30 lbs.
How many milligrams should the child receive per day? (round to the nearest whole
number) NUMERIC VALUE ONLY
1.) 30/2.2=13.64
2.) 13.64*100=1364
#17
The nurse is caring for a client who has been ordered diphenhydramine 12.5mg po q 4-6
hours for itching. The nurse has available diphenhydramine 25mg/5mL.
How many milliliters would be needed to administer 12.5mg? (Record the numerical
portion only)
(12.5/25)*5=2.5
#18
An infant weighing 6 lbs 8 ounces is to receive 150 ml of blood over 3 hours.
Using a microdrip (50 gtt/ml), how many drops per minute are needed? NUMERIC
VALUE ONLY
(50*150)/180=42
#19
An order is placed for a 5-year-old to receive Erythromycin 75mg IM q 6 hours for an
infection. The recommended max safe dose of erythromycin for a child is 20mg/kg/24
hours divided in doses every 6 hours. The child’s weight is 40 pounds.
What is the recommended max safe and therapeutic single dose for this child in mg?
(Round to the nearest number) NUMERIC VAULE ONLY
1.) 40/2.2=18.19
2.) 18.19*20=363.64
3.) 363.64/4=91
#20
An order is placed for a 5-year-old to receive Erythromycin 75mg IM q 6 hours for an
infection. The recommended max safe dose of erythromycin for a child is 20mg/kg/24
hours divided in doses every 6 hours. The child’s weight is 40 pounds.
Erythromycin is supplied 125mg/ml. How many milliliters will the nurse administer per
dose? (Round to the nearest tenths place) NUMERIC VALUE ONLY
75/125=0.6