Almost every pediatric medication is dosed by weight. A small math error can mean a big overdose for a small child, so always check that the dose is in the safe range.
Step 1: Get the weight in kilograms
Step 2: Check the safe dose range
- Multiply the low and high mg/kg/day limits by the child's weight.
- If the drug is split into doses, divide the daily range by the number of doses.
- Compare the ordered dose to that range.
A child weighs 22 lb. The safe range for a drug is 20 to 40 mg/kg/day, divided every 8 hours. The order is 125 mg every 8 hours. Is it safe?
Show answer
Yes. 22 ÷ 2.2 = 10 kg. Daily range: 200 to 400 mg. Every 8 hours is 3 doses, so 66.7 to 133.3 mg per dose. 125 mg is inside the range.
Maintenance IV fluids: the 4-2-1 rule
| Weight | Per hour |
|---|---|
| First 10 kg | 4 mL/kg/hr |
| Next 10 kg (11 to 20 kg) | 2 mL/kg/hr |
| Each kg above 20 | 1 mL/kg/hr |
Example: a 25 kg child. (10 × 4) + (10 × 2) + (5 × 1) = 40 + 20 + 5 = 65 mL/hr.
Fluid bolus
For dehydration or shock, providers often order an isotonic fluid bolus (normal saline or lactated Ringer's) of 10 to 20 mL/kg. A 15 kg child getting 20 mL/kg receives 300 mL. Reassess after every bolus.
Urine output
Children should make at least about 1 mL/kg/hr of urine. Teens and adults: at least 0.5 mL/kg/hr. Weighing diapers works: 1 gram of wet diaper weight is about 1 mL of urine.
More formulas: Dosage calculation formulas.
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Quick answers
How do you check a pediatric safe dose range?
Convert the weight to kilograms, multiply by the low and high mg/kg limits, divide by the number of doses if needed, and compare the order to that range.
What is the 4-2-1 rule for pediatric fluids?
4 mL/kg/hr for the first 10 kg, 2 mL/kg/hr for the next 10 kg, and 1 mL/kg/hr for each kg above 20.
Evidence & Clinical Sources
- Vallerand & Sanoski, Davis's Drug Guide for Nurses, F.A. Davis
- ISMP List of High-Alert Medications
- Hockenberry, Wong's Essentials of Pediatric Nursing, Elsevier
Reviewed against current guidelines and drug labels. Always follow your program, a current drug reference, and facility policy. Our sources policy
For learning only. Lab ranges and policies vary. Always follow your nursing program, a current drug reference, and your facility's policies.