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

Amoxicillin Dosing for Pediatric Patients

For most pediatric respiratory infections, amoxicillin should be dosed at 45 mg/kg/day divided into 2 doses for mild-to-moderate infections, or 90 mg/kg/day divided into 2 doses for severe infections or areas with high pneumococcal resistance. 1

Standard Dosing by Indication

Respiratory Tract Infections (Most Common)

Mild to Moderate Infections:

• 45 mg/kg/day divided every 12 hours is the preferred regimen for uncomplicated community-acquired pneumonia and other respiratory infections 1
• This dosing provides adequate coverage for typical pathogens while minimizing adverse effects 1

Severe Infections or High Resistance Areas:

• 90 mg/kg/day divided every 12 hours should be used when pneumococcal resistance is suspected or confirmed 1
• The FDA label supports dosing up to 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours for severe lower respiratory tract infections 2
• Maximum daily dose is 4000 mg (4 g) per day 1

Group A Streptococcal Infections (Including Scarlet Fever and Impetigo)

• 50-75 mg/kg/day divided into 2 doses for 10 days, not exceeding 1000 mg per dose 1, 3
• Treatment must continue for at least 10 days to prevent acute rheumatic fever 2
• Patients become non-contagious after 24 hours of therapy 1

Age-Specific Considerations

Infants Under 3 Months (12 Weeks)

• Maximum dose is 30 mg/kg/day divided every 12 hours due to immature renal function 2
• No specific dosing recommendations exist for infants 2 weeks to 2 months of age in current guidelines 4

Children 3 Months and Older

Weight-based dosing is preferred over age-based dosing 1, 5

For children weighing less than 40 kg 2:

• Mild/moderate infections: 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours
• Severe infections: 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours

For children weighing 40 kg or more 2:

• Mild/moderate: 500 mg every 12 hours OR 250 mg every 8 hours
• Severe: 875 mg every 12 hours OR 500 mg every 8 hours

Treatment Duration

• 7-10 days for most respiratory infections, with pneumonia specifically requiring 10 days 1
• 10 days mandatory for Group A Streptococcal infections to prevent rheumatic fever 1, 2
• Recent evidence suggests 5-day courses may be non-inferior to 10-day courses for uncomplicated CAP, though 7-10 days remains standard practice 6, 7

Renal Impairment Adjustments

For patients with GFR 10-30 mL/min 2:

• 500 mg or 250 mg every 12 hours (depending on severity)

For patients with GFR less than 10 mL/min 2:

• 500 mg or 250 mg every 24 hours
• Additional dose during and after hemodialysis 2

Critical Administration Details

Every prescription should include 5:

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

Administration tips 2:

• Give at the start of meals to minimize gastrointestinal intolerance 2
• Suspension can be mixed with formula, milk, fruit juice, water, or cold drinks and taken immediately 2
• Shake suspension well before each use 2

Monitoring and Follow-Up

• Clinical improvement should occur within 48-72 hours 1
• If no improvement by 72 hours, reassess diagnosis and consider alternative antibiotics 1, 3
• Complete the full prescribed course even if symptoms improve 1

Common Adverse Effects

• Gastrointestinal disturbances (diarrhea, nausea, vomiting) are most common 1
• Rash, urticaria, and hypersensitivity reactions may occur 1
• Monitor for these effects throughout treatment 3

Important Clinical Pitfalls

Viral coinfection reduces amoxicillin efficacy - children with combined viral and bacterial infections may have lower middle ear fluid penetration of amoxicillin and may require higher dosing (90 mg/kg/day) 8

Twice-daily dosing improves adherence compared to three-times-daily regimens, making the 45-90 mg/kg/day divided every 12 hours the preferred approach over more frequent dosing 1, 5

MRSA coverage - if MRSA is suspected or confirmed, amoxicillin alone will not be effective and alternative antibiotics must be considered 3