Overview
This lecture explains three methods for calculating pediatric drug dosages: Fried's Rule, Young's Rule, and Clark's Rule, using a sample problem to demonstrate each.
Methods for Pediatric Dosage Calculation
Fried's Rule
- Used for infants and younger children.
- Formula: Pediatric dose = (Age in months / 150) × Adult dose.
- Example: For a 15-month-old infant (adult dose = 1000 mg): (15/150) × 1000 mg = 100 mg.
Young's Rule
- Applied for older children based on age in years.
- Formula: Pediatric dose = [Age in years / (Age in years + 12)] × Adult dose.
- Convert months to years for calculation.
- Example: 15 months = 1.25 years, so [1.25 / (1.25 + 12)] × 1000 mg = 94 mg.
Clark's Rule
- Uses child's weight in pounds for dosage.
- Formula: Pediatric dose = (Weight in lbs / 150) × Adult dose.
- Example: 20 lbs child: (20/150) × 1000 mg = 133 mg.
Comparing Results
- Fried's Rule: 100 mg for the sample problem.
- Young's Rule: 94 mg for the sample problem.
- Clark's Rule: 133 mg for the sample problem.
- Method selection depends on the child's age, weight, and clinical context.
Key Terms & Definitions
- Fried's Rule — Dosage calculation based on age in months, often for infants.
- Young's Rule — Dosage calculation based on age in years, for older children.
- Clark's Rule — Dosage calculation based on child's weight in pounds.
- Pediatric Dose — The correct drug dose for a child, adjusted from the adult dose.
Action Items / Next Steps
- Practice pediatric dosage calculations using all three rules with different ages and weights.
- Review the formulas and memorize when to apply each rule.