What is the recommended dosage of amoxicillin (amoxicillin) for pediatric patients?

Amoxicillin Dosing for Pediatric Patients

For most pediatric infections, amoxicillin should be dosed at 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

Standard Dosing by Weight and Severity

Children Weighing Less Than 40 kg

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

• 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours 3
• This provides adequate coverage for typical pathogens while minimizing adverse effects 1

Severe Infections or Lower Respiratory Tract Infections:

• 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours 3
• For areas with high pneumococcal resistance or severe pneumonia, increase to 90 mg/kg/day divided every 12 hours 1, 2, 4

Children Weighing 40 kg or More

Mild to Moderate Infections:

• 500 mg every 12 hours OR 250 mg every 8 hours 3

Severe Infections:

• 875 mg every 12 hours OR 500 mg every 8 hours 3

Age-Specific Considerations

Infants Less Than 3 Months (12 Weeks)

• Maximum dose: 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 3
• No dosing recommendations exist for infants with impaired renal function in this age group 3

Children 3 Months and Older

• Follow weight-based dosing as outlined above 1, 3
• Twice-daily dosing (every 12 hours) improves adherence compared to three-times-daily regimens 1

Indication-Specific Dosing

Community-Acquired Pneumonia

Outpatient Treatment:

• 90 mg/kg/day divided every 12 hours for children under 5 years 4
• 90 mg/kg/day divided every 12 hours (maximum 4 g/day) for children 5 years and older 4
• The higher dose (90 mg/kg/day) is essential to overcome pneumococcal resistance; underdosing with 40-45 mg/kg/day is a common and dangerous error 4

Treatment Duration:

• 7-10 days for most respiratory infections 1, 2
• Pneumonia specifically requires 10 days of treatment 1, 2

Group A Streptococcal Infections (Including Scarlet Fever)

• 50-75 mg/kg/day divided into 2 doses for 10 days, not exceeding 1000 mg per dose 1, 2
• The 10-day duration is mandatory to prevent rheumatic fever 1, 2
• Patients become non-contagious after 24 hours of therapy 2

Acute Otitis Media

• Standard dose: 45 mg/kg/day divided every 12 hours 1
• High-dose: 90 mg/kg/day divided every 12 hours for patients who received antibiotics within the past 4-6 weeks or in areas with high resistance 2

Renal Impairment Adjustments

GFR 10-30 mL/min:

• 500 mg or 250 mg every 12 hours, depending on infection severity 3

GFR Less Than 10 mL/min:

• 500 mg or 250 mg every 24 hours 3

Hemodialysis:

• 500 mg or 250 mg every 24 hours, with an additional dose during and at the end of dialysis 3

Important: Patients with GFR less than 30 mL/min should NOT receive the 875 mg dose 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

• Administer at the start of a meal to minimize gastrointestinal intolerance 3
• For oral suspension, shake well before each use 3
• Refrigeration is preferable but not required; discard unused suspension after 14 days 3

Monitoring and Follow-Up

Expected Clinical Response:

• Clinical improvement should occur within 48-72 hours of starting treatment 1, 2
• If no improvement by 72 hours, reassess the diagnosis and consider alternative antibiotics 1, 2

Treatment Completion:

• Continue for minimum 48-72 hours beyond symptom resolution 3
• Complete the full prescribed course even if symptoms improve 1, 2

Common Adverse Effects

• Gastrointestinal disturbances (diarrhea, nausea, vomiting) are most common 1, 2
• Rash, urticaria, and hypersensitivity reactions may occur 1, 2
• Monitor patients throughout treatment for these effects 1

Critical Pitfalls to Avoid

Underdosing for Pneumonia:

• Using 40-45 mg/kg/day instead of the recommended 90 mg/kg/day for pneumonia is inadequate for resistant Streptococcus pneumoniae 4, 5

Inadequate Duration for Streptococcal Infections:

• Less than 10 days of treatment for Group A Streptococcal infections risks rheumatic fever 1, 2

MRSA Coverage:

• Amoxicillin alone will not be effective if MRSA is suspected or confirmed; alternative antibiotics must be considered 1

Viral Coinfection:

• Amoxicillin penetration into middle ear fluid is reduced during viral coinfection, potentially requiring higher doses 5