What is the dosage of amoxicillin (250mg/5ml) for a pediatric patient based on weight?

Amoxicillin Dosing for Pediatric Patients (250mg/5ml Suspension)

For most common pediatric infections, amoxicillin should be dosed at 40-50 mg/kg/day divided into two doses (every 12 hours), with the specific dose depending on infection severity and type. 1

Weight-Based Dosing Algorithm

For Children ≥3 Months and <40 kg:

Mild to Moderate Infections (otitis media, skin infections, uncomplicated respiratory infections):

• 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours 1
• Using 250mg/5ml suspension: Calculate total daily dose in mg, divide by 2 for twice-daily dosing
• Example: 15 kg child = 375 mg/day = 187.5 mg per dose = 3.75 ml twice daily 1

Severe Infections (lower respiratory tract, resistant organisms):

• 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours 1
• Using 250mg/5ml suspension: Calculate total daily dose in mg, divide by 2 for twice-daily dosing
• Example: 15 kg child = 675 mg/day = 337.5 mg per dose = 6.75 ml twice daily 1

High-Dose Regimen (acute otitis media, pneumonia in areas with resistant Streptococcus pneumoniae):

• 90 mg/kg/day divided into two doses (maximum 4000 mg/day) 2
• This requires the higher concentration suspension (400mg/5ml) or tablets for practical administration 2

For Children <3 Months:

• Maximum 30 mg/kg/day divided every 12 hours due to immature renal function 1
• Do NOT exceed this dose in neonates and young infants 1

For Children ≥40 kg:

• Use adult dosing: 500 mg every 12 hours for mild/moderate infections OR 875 mg every 12 hours for severe infections 1

Specific Infection Guidelines

Acute Otitis Media:

• 40 mg/kg/day divided twice daily for 5 days 2
• Alternative: 90 mg/kg/day divided twice daily in areas with high penicillin resistance 2

Community-Acquired Pneumonia (outpatient):

• Children <5 years: 90 mg/kg/day divided twice daily 2
• Children ≥5 years: 90 mg/kg/day divided twice daily (maximum 4000 mg/day) 2

Streptococcal Pharyngitis:

• 50 mg/kg once daily (maximum 1000 mg) for 10 days 2
• Alternative: 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 2

Skin/Soft Tissue Infections:

• Mild/moderate: 25 mg/kg/day divided every 12 hours 1
• Severe: 45 mg/kg/day divided every 12 hours 1

Critical Dosing Considerations

Duration of Therapy:

• Continue for minimum 48-72 hours beyond symptom resolution 1
• Streptococcal infections require minimum 10 days to prevent rheumatic fever 1
• Most common infections: 5-10 days 2

Administration Instructions:

• Give at the start of meals to minimize gastrointestinal intolerance 1
• Shake suspension well before each use 1
• Can mix with formula, milk, fruit juice, water, or cold drinks; must be taken immediately after mixing 1
• Refrigeration preferred but not required; discard after 14 days 1

Renal Impairment:

• GFR 10-30 mL/min: 250-500 mg every 12 hours 1
• GFR <10 mL/min: 250-500 mg every 24 hours 1
• No specific pediatric renal dosing guidelines available for children <3 months 1

Common Pitfalls to Avoid

Underdosing: The traditional 20-40 mg/kg/day regimen may be inadequate for resistant organisms; current evidence supports 40-90 mg/kg/day for most infections 2, 3, 4

Age-based vs. Weight-based Dosing: Always use weight-based dosing (mg/kg) rather than age-based dosing for accuracy 3, 5

Suspension Concentration Confusion: The 250mg/5ml suspension requires larger volumes for high-dose regimens; ensure adequate supply is dispensed 5

Prescription Clarity: Include on prescription: total daily dose in mg/kg, number of divided doses, duration, indication, and child's weight 3

Twice vs. Three Times Daily: Evidence supports twice-daily dosing (every 12 hours) as equally effective and superior for compliance compared to three-times-daily dosing 4