Pediatric Dosages
                        

Pediatric dosages are calculated by safety and therapeutic recommended minimum and maximum dose range that is provided in a drug handbook. It's a calculation process to make sure health care professionals do not overdose the child as well as under dosing the child. Ex) 10 to 15 mg/kg/day [10 would be the minimum dose & 15 would be the maximum dose]
[If 5 was the minimum dose, it would be under dosing 10 & if 25 was the maximum dose, it would overdose 15]

Pediatric dosages are also calculated by a 24 hour dosage range usually for antibiotics and 24 hour doses can be calculated into an individual dose. Pediatric IV solutions are calculated as well.
                                                                                       

1) A child weighs 22 lbs. The child is prescribed acetaminophen for pain & fever. The recommended dose is 10 to 15 mg/kg/dose q4-6h. How many mg/dose will the child receive when given acetaminophen?

Step 1: 22 lbs / 2.2kg = 10kg

Step 2:  10 mg = 1 kg
                 X mg  = 10 kg  -------< 10mg X 10 kg / 1 kg = 100 mg/dose

Step 3: 15 mg = 1 kg
                X mg  = 10 kg -------< 15 mg X 10 kg / 1 kg = 150 mg/dose

**[The child may receive 100 to 150 mg/dose each time he or she is given acetaminophen]

 

 



2) Doctor ordered Gentamicin 50mg q8h for a child who weighs 50 lbs. The recommended dosage is 6 - 7.5 mg/kg/day 3x a day. Is the dose safe?

Step 1: 50 lbs / 2.2 kg = 22.7 kg

Step 2: 22.7 kg X 6 mg/kg/day = 136.2 mg/kg/day

Step 3: 22.7 kg X 7.5 mg/kg/day = 170.25
mg/kg/day

Step 4: 50 mg X 3 (q8h) = 150 mg/day

** Yes the dose is safe because 150 mg is within the safe and therapeutic dose range of 136.2 - 170.25
mg/kg/day

 

 



3) An infant is admitted to the hospital to rule out sepsis (a severe illness in which the bloodstream is overwhelmed by bacteria). The infant weighs 8 lbs. Ampicillin is prescribed. The recommended dose is 200 to 400 mg/kg/24h q4-6h. Calculate the 24 hour dose range that is to be given to the infant.

Step 1: 8 lbs / 2.2 kg = 3.6
kg


Step 2: 3.6 kg X 200 mg/kg/24h = 720 mg/24h [cancel out kg]

Step 3: 3.6 kg X 400 mg/kg/24h = 1440 mg/24h [cancel out kg]

** 720 mg/24h to 1410 mg/24h will be the 24 hour dose range that the infant can receive in a 24 hour period.

 

 



4) A child weighs 22 lbs. The physician prescribes ampicillin 100 to 200 mg/kg/24h divided q6h which would be the recommended dose range as well. Calculate the individual dose range for ampicillin.

Step 1:
22 lbs / 2.2 kg = 10 kg

Step 2: 10 kg X 100 mg/kg/24h = 1000 mg/24h [cancel out kg]

Step 3: 10 kg  X 200 mg/kg/24h = 2000 mg/24h [cancel out kg]

Step 4: 24 hrs / 6 (q6h) = 4 hours or 4 doses

Step 5: 1000 mg/24h [divide] 4 doses = 250 mg/dose [cancel out 24h]

Step 6: 2000 mg/24h [divide] 4 doses = 500 mg/dose [cancel out 24h]

** 250 to 500 mg/dose would be the individual dose range

 

 



5) Infuse 100 ml of 0.9% NS over 5 hours to a 6 month old child. How many ml per hour should the IV pump be programmed for?

**Medication that is being infused with an IV pump, formula will be calculated with hours
An IV pump is a device used to control the delivery of fluids into the vein through an intravenous catheter
.

Formula:    Total volume to be infused
                    ___________________  =  X ml/h
                         Total time in hours

Setup:         100 ml
                    _______  =   20 ml/h
                       5 hrs



 

6) Infuse 200 ml Lactated Ringer's solution (LR) over 4 hours to an 8 year old child. The tubing drop factor is 60 gtt/ml. How many drops per minute of LR should be infused?
**Medication that is being infused with an Buretrol (soluset), formula will be calculated with minutes.
A Buretrol is a device used to deliver IV fluids that holds 100-150 ml. This device can deliver medication safely into the child.

Formula:    Total volume to be infused
                   ____________________   X Drop Factor = X gtt/min
                        Total time in minutes

Setup:   Convert 4 hours to minutes [4 X 60 min = 240 minutes]

                               200 ml
                              ______  X 60 gtt/ml = 50 gtt/min
                               240 min


 

7) Doctor ordered Keflex 250 mg qid. The drug is supplied 125mg/5ml. The child weighs 50 lbs. The recommended dose is 25 - 50 mg/kg/day 4x a day. Is the dose safe? How many ml do you need to administer per dose and day?

Step 1: 50 lbs / 2.2 kg = 22.7 kg

Step 2: 22.7 kg X 25 mg/kg/day = 567.5

Step 3: 22.7 kg X 50 mg/kg/day = 1135

Step 4: 250 mg X 4 (qid) = 1000 mg

**Yes the dose is safe because 1000 mg is within the safety & therapeutic recommended dose range of 567.5 - 1135 mg/kg/day

Step 5:   125 mg = 5 ml
                250 mg = X ml --------< 250 mg X 5 ml / 125 mg = 10 ml/dose

Step 6:   125mg = 5 ml
              1000 mg = X ml -------< 1000 mg X 5 ml / 125 mg = 40 ml/day



Note: A doctor at times may prescribe an adult dose to a child, the health care professional would calculate the final pediatric dose by using the Clark's rule, Fried's rule, or Young's rule depending on the child's age. This tutorial is provided above this page.