1. Pediatric and Adult Dosages Based on Body Weight
Chapter 13
Pediatric and Adult Dosages Based on Body Weight
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2. Caution
Those who administer drugs to patients are legally responsible for recognizing incorrect and unsafe dosages
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3. Administering Medications to Children
Children aged birth to one year have a high percentage of body water
Children aged 1 to 12 years metabolize drugs more readily than adults
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4. Administering Medications to Children (Continued)
Immature physiological processes related to absorption, distribution, metabolism and excretion
Place children at risk for overdose, toxic reactions, and death
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5. Remember 1 kg = 2.2 lbs 1 lb to 16 oz
When converting pound to kilograms
Round kilogram weight to one decimal place (tenths)
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6. Pounds to Kilograms Convert 45 lb to kg
Think ½ of 45 = approximately 23
45 lb = 45 lb ÷ 2.2 lb/kg = 20.5 kg
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7. Conversions Convert 10 lbs 12 oz to kg Then
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8. Verifying Safe Dosages
Order: morphine sulfate 1.8 mg IM stat
The child weighs 79 lbs
Is the dose safe?
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9. Verifying Safe Dosages (Continued)
Convert 79 lb to kg
79 lbs = 79 lb ÷ 2.2 lb/kg = 35.9 kg
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10. Verifying Safe Dosages (Continued)
Calculate mg/kg as recommended by a drug resource
Resource indicates the usual IM/subcut dosage may be initiated at 0.05 mg/kg/dose
The dose is safe and matches the order
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11. Body Weight To verify safe pediatric dosage
Convert child’s weight from pounds to kilograms (rounded to tenth)
Calculate safe weight in mg/kg or mcg/kg
Compare ordered dosage to recommended dosage and decide if dosage is safe
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12. Body Weight (Continued)
To verify safe pediatric dosage
If safe, calculate the amount to give and administer the dose
If dosage seems unsafe, contact ordering practitioner
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13. Verifying Safe Pediatric Dosages: Body Weight Method
Convert child’s weight from pounds to kilograms (rounded to tenths)
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14. Verifying Safe Pediatric Dosages: Body Weight Method (Continued)
Calculate safe dosage in mg per kg or mcg per kg (rounded to tenths) for a child of this weight
As recommended by a reputable drug reference
Multiply mg per kg by child’s weight in kg
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15. Verifying Safe Pediatric Dosages: Body Weight Method (Continued)
Compare ordered dose to recommended dose
Decide if dosage is safe
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16. Verifying Safe Pediatric Dosages: Body Weight Method (Continued)
If safe:
Calculate amount to administer dose
If dosage seems unsafe, consult with ordering practitioner
NOTE: Dosage per kg may be mg per kg, mcg per kg, g per kg, mEq per kg, units per kg, milliunits per kg, etc.
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17. Calculation of Safe Dosage
Order: amoxicillin 200 mg p.o. q.8h for a child who weighs 22 lbs
Is this dosage safe?
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18. Calculation of Safe Dosage (Continued)
Convert lb to kg
Approximate equivalent: 1 kg = 2.2 lbs
Think: ½ of 22 = 11
22 lbs = 22 lb ÷ 2.2 lb/kg = 10 kg
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19. Calculation of Safe Dosage (Continued)
Calculate recommended dosage
Amoxil (amoxicillin) label describes recommended dosage as 20 to 40 mg per kg per day in divided doses every 8 hours
Label recommends that total daily dosage be divided and administered every 8 hours, resulting in 3 doses in 24 hours
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20. Calculation of Safe Dosage (Continued)
Calculate minimum and maximum dosage for each single dose
Minimum total daily dosage
20 mg/kg/day × 10 kg = 200 mg per day
Minimum dosage for each single dose
200 mg ÷ 3 doses = 66.7 mg per dose
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21. Calculation of Safe Dosage (Continued)
Maximum total daily dosage
40 mg/kg/day × 10 kg = 400 mg/day
400 mg ÷ 3 doses = mg/dose
Single dosage is 66.7 to mg per dose
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22. Calculation of Safe Dosage (Continued)
Decide if ordered dosage is safe
200 mg
Allowable, safe dosage is 66.7 to mg per dose
Dosage is considered too high and not safe
Contact physician to discuss order
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23. Caution
Once an adolescent attains a weight of 50 kg (110 lbs) or greater, the standard adult dosage is frequently prescribed
Verify that the order for a child’s dosage does not exceed the maximum
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24. Quick Review
To use the body weight method to verify the safety of pediatric and adult dosages
Convert body weight from pounds and ounces to kilograms: 1 kg = 2.2 lbs; 1 lb = 16 oz
Calculate the recommended safe dosage in mg/kg
Compare the ordered dosage with the recommended dosage to decide if it is safe
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25. Quick Review (Continued)
If the dosage is safe, calculate the amount to give for 1 dose; if not safe, notify the prescriber
Combination drugs are ordered by dose volume; check a reputable drug reference to be sure the dose ordered contains the recommended safe amount
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