What is the recommended dose of Amoxicillin (Amoxil) syrup for pediatric patients?

Amoxicillin Syrup Dosing for Pediatric Patients

For children ≥3 months and <40 kg, use 45 mg/kg/day divided every 12 hours for mild to moderate infections, or 90 mg/kg/day divided every 12 hours for severe infections or areas with high pneumococcal resistance, with a maximum daily dose of 4000 mg. 1, 2, 3

Standard Dosing Algorithm by Infection Severity

Mild to Moderate Infections

• Children ≥3 months and <40 kg: 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours 3
• Preferred regimen: 45 mg/kg/day divided every 12 hours improves adherence compared to three-times-daily dosing 1
• Indications: Uncomplicated ear/nose/throat infections, skin infections, genitourinary tract infections 3

Severe Infections or High-Resistance Areas

• Children ≥3 months and <40 kg: 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours 3
• High-dose regimen: 90 mg/kg/day divided every 12 hours for community-acquired pneumonia, severe infections, or areas with >10% penicillin-resistant S. pneumoniae 1, 2
• Indications: Lower respiratory tract infections, children <2 years, recent antibiotic exposure within 30 days, daycare attendance 1, 2

Neonates and Infants <3 Months

Maximum dose: 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 3

This lower dosing is critical because renal elimination of amoxicillin is impaired in this age group, and higher doses risk accumulation and toxicity 3.

Indication-Specific Dosing

Group A Streptococcal Infections (Pharyngitis, Scarlet Fever)

• Dose: 50-75 mg/kg/day divided into 2 doses for 10 days 1, 2
• Maximum per dose: 1000 mg 1
• Duration: Full 10 days mandatory to prevent rheumatic fever 1, 3
• Non-contagious: After 24 hours of therapy 1

Community-Acquired Pneumonia

• Mild to moderate: 45 mg/kg/day divided every 12 hours 1, 2
• Severe or high resistance: 90 mg/kg/day divided every 12 hours 1, 2
• Duration: 10 days 1, 2

Acute Bacterial Sinusitis

• Children ≥2 years without risk factors: 45 mg/kg/day divided every 12 hours 2
• Children <2 years, daycare, or recent antibiotic use: 80-90 mg/kg/day divided every 12 hours 2

Renal Impairment Adjustments

• GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 3
• GFR <10 mL/min: 500 mg or 250 mg every 24 hours 3
• Hemodialysis: 500 mg or 250 mg every 24 hours, with additional dose during and at end of dialysis 3
• Important: Children with GFR <30 mL/min should NOT receive the 875 mg dose 3

Treatment Duration

• Most respiratory infections: 7-10 days 1, 2
• Pneumonia: 10 days specifically 1, 2
• Group A Streptococcal infections: 10 days mandatory 1, 3
• General rule: Continue for minimum 48-72 hours beyond symptom resolution or bacterial eradication 3

Critical Administration Details

Prescription Requirements

Every prescription must include: 1

• Total daily dose in mg/kg/day
• Number of divided doses per day
• Duration of therapy
• Indication for prescription
• Child's weight

Administration Instructions

• Timing: Give at the start of a meal to minimize gastrointestinal intolerance 3
• Suspension preparation: Place directly on child's tongue OR mix with formula, milk, fruit juice, water, ginger ale, or cold drinks and administer immediately 3
• Storage: Shake well before each use; refrigeration preferable but not required; discard unused portion after 14 days 3

Monitoring and Follow-Up

• Expected improvement: Within 48-72 hours of starting treatment 1, 2
• If no improvement by 72 hours: Reassess diagnosis, consider atypical pathogens, evaluate for complications, consider alternative antibiotics 1, 2
• Complete full course: Even if symptoms improve before completion 1

Common Adverse Effects

• Most common: Diarrhea, nausea, vomiting (gastrointestinal disturbances) 1, 2
• Hypersensitivity: Rash, urticaria 1, 2
• Monitoring: Watch for these effects throughout treatment 1

Critical Clinical Pitfalls to Avoid

Dosing Errors

• Twice-daily dosing (every 12 hours) is preferred over three-times-daily to improve adherence 1
• Verify suspension concentration (125 mg/5 mL vs 250 mg/5 mL) before calculating volume to avoid dosing errors 4
• Weight-based dosing is more accurate than age-based for optimal therapeutic outcomes 5

Resistance Considerations

• MRSA coverage: Amoxicillin alone will NOT be effective; alternative antibiotics required 1
• β-lactamase-producing organisms: (H. influenzae, M. catarrhalis) require amoxicillin-clavulanate instead 2
• Subtherapeutic doses promote antimicrobial resistance and lead to treatment failure 4

Special Populations

• Children <2 years with pneumonia: Consider high-dose regimen (90 mg/kg/day) 1, 2
• Incomplete H. influenzae type b vaccination: Use amoxicillin-clavulanate instead of amoxicillin alone 2
• Recent antibiotic exposure (within 30 days): Use high-dose regimen (90 mg/kg/day) 1, 2