What is the recommended dose of cephalexin (antibiotic) for a child weighing 80.6 pounds?

Recommended Dose of Cephalexin for a Child Weighing 80.6 Pounds

The recommended dose of cephalexin for a child weighing 80.6 pounds (approximately 36.6 kg) is 25-50 mg/kg/day divided into 2-4 doses, which translates to approximately 915-1830 mg per day total, typically given as 250-500 mg every 6 hours or 500-750 mg every 12 hours. 1

Dosing Calculation

• 80.6 pounds = 36.6 kg (conversion factor: 1 kg = 2.2 pounds)
• Standard pediatric dosing range: 25-50 mg/kg/day divided into 2-4 doses 1
• For this child:
  • Minimum dose: 36.6 kg × 25 mg/kg/day = 915 mg/day
  • Maximum dose: 36.6 kg × 50 mg/kg/day = 1830 mg/day

Dosing Schedule Options

• Four times daily (q.i.d.) dosing:

  • 225-450 mg every 6 hours 1
  • Practically administered as 250-500 mg every 6 hours

• Twice daily (b.i.d.) dosing:

  • 450-900 mg every 12 hours 1
  • Practically administered as 500-750 mg every 12 hours

Condition-Specific Dosing

• For streptococcal pharyngitis and skin/skin structure infections:

  • Can use twice daily (b.i.d.) dosing 1
  • 500 mg every 12 hours would be appropriate for this child

• For otitis media:

  • Higher dosing of 75-100 mg/kg/day in 4 divided doses is required 1
  • For this child: 2750-3660 mg/day or approximately 700-900 mg every 6 hours

• For β-hemolytic streptococcal infections:

  • Treatment should continue for at least 10 days 1

Formulation Options

• For a child this size (80.6 pounds/36.6 kg):
  • Capsules or tablets (250 mg or 500 mg) are appropriate 1
  • Suspension can also be used if needed:
    • 250 mg/5 mL: 2-4 teaspoons (10-20 mL) per dose for q.i.d. dosing 1
    • 250 mg/5 mL: 4-8 teaspoons (20-40 mL) per dose for b.i.d. dosing 1

Important Considerations

• For severe infections, the dosage may be doubled 1
• Cephalexin is well absorbed from the gastrointestinal tract 2
• Children may need higher doses per kilogram than adults due to greater body water turnover 2
• Cephalexin has a low incidence of side effects, primarily mild gastrointestinal upset, rash, or urticaria 3
• Cephalexin is effective against common pathogens causing respiratory, skin, and urinary tract infections 3, 4

Administration Guidelines

• Cephalexin can be administered with or without food 1
• If using suspension, it must be prepared at time of dispensing and stored in refrigerator 1
• The prepared suspension remains potent for 14 days when refrigerated 1