What is the appropriate dose of amoxicillin (200 mg/5 ml suspension) for a child weighing 8.62 kg?

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Last updated: September 15, 2026 • View editorial policy

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Amoxicillin Dosing for 8.62 kg Child

For a child weighing 8.62 kg, the appropriate amoxicillin dose depends on the infection severity and type, but generally ranges from 172-388 mg per day (4.3-9.7 mL of 200mg/5mL suspension), divided into 2-3 doses.

Dosing by Infection Type and Severity

For Mild to Moderate Infections (Ear/Nose/Throat, Skin, Genitourinary)

  • Standard dose: 20-25 mg/kg/day divided every 8-12 hours 1
    • Calculation: 8.62 kg × 20-25 mg/kg = 172-216 mg/day
    • Volume: 4.3-5.4 mL/day of 200mg/5mL suspension
    • Divided dosing: 2.2-2.7 mL every 12 hours OR 1.4-1.8 mL every 8 hours

For Severe Infections or High-Risk Situations

  • High dose: 40-45 mg/kg/day divided every 8-12 hours 1
    • Calculation: 8.62 kg × 40-45 mg/kg = 345-388 mg/day
    • Volume: 8.6-9.7 mL/day of 200mg/5mL suspension
    • Divided dosing: 4.3-4.9 mL every 12 hours OR 2.9-3.2 mL every 8 hours

For Respiratory Tract Infections (Including Pneumonia)

  • Recommended dose: 40-45 mg/kg/day divided every 8-12 hours 2, 3
    • This higher dose is preferred for lower respiratory tract infections regardless of severity
    • Volume: 8.6-9.7 mL/day divided into 2-3 doses

High-Risk Factors Requiring Higher Doses

Use 40-45 mg/kg/day (high-dose) if the child has:

  • Age < 2 years (this child at 8.62 kg is likely < 2 years)
  • Attends daycare
  • Received antibiotics within the past 30 days
  • Lives in area with high pneumococcal resistance (>10% penicillin non-susceptibility) 4
  • Moderate to severe illness presentation

Practical Prescribing

For this 8.62 kg child, I recommend:

  • 345 mg/day (8.6 mL/day) divided as 4.3 mL every 12 hours for most infections
  • This provides 40 mg/kg/day, which is appropriate for:
    • Any respiratory tract infection
    • Moderate to severe infections
    • High-risk patients (likely given the low weight)

For confirmed mild infections in a low-risk child:

  • 215 mg/day (5.4 mL/day) divided as 2.7 mL every 12 hours
  • This provides 25 mg/kg/day

Special Considerations for Infants < 3 Months

If this child is < 3 months old (< 12 weeks), the maximum dose is 30 mg/kg/day divided every 12 hours due to immature renal function 1:

  • Calculation: 8.62 kg × 30 mg/kg = 259 mg/day
  • Volume: 6.5 mL/day divided as 3.2 mL every 12 hours

Administration Instructions

  • Give at the start of meals to minimize gastrointestinal side effects 1
  • Shake suspension well before each dose
  • Can mix with formula, milk, fruit juice, or water if needed; administer immediately after mixing 1
  • Continue treatment for minimum 48-72 hours after symptom resolution 1
  • For streptococcal infections, treat for at least 10 days to prevent rheumatic fever 1

Common Pitfalls to Avoid

  • Don't underdose based on "adult maximum": The 8.62 kg child is well below weight thresholds where adult maximum doses become relevant
  • Don't use standard dose for pneumonia: Respiratory infections require 40-45 mg/kg/day regardless of severity 2
  • Don't forget age-based restrictions: If < 3 months, cap at 30 mg/kg/day 1
  • Don't use twice-daily dosing for standard dose: 20-25 mg/kg/day should be divided every 8 hours (three times daily), while 40-45 mg/kg/day can be given every 12 hours (twice daily) 1

References

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.