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

Amoxicillin Syrup Dosing for Pediatric Patients

For children ≥3 months old, amoxicillin dosing is weight-based and indication-specific: use 45 mg/kg/day divided every 12 hours for mild-to-moderate respiratory infections, and 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

Standard Dosing Algorithm by Indication

Mild-to-Moderate Respiratory Tract Infections

• 45 mg/kg/day divided every 12 hours is the recommended dose for uncomplicated community-acquired pneumonia, acute otitis media, and sinusitis in children ≥3 months and <40 kg 1, 2
• This provides adequate coverage for most susceptible pathogens including Streptococcus pneumoniae, non-β-lactamase-producing Haemophilus influenzae, and Streptococcus pyogenes 1
• The FDA label supports 25 mg/kg/day divided every 12 hours for mild infections, though current guidelines favor the higher 45 mg/kg/day dosing 2

Severe Infections or High-Resistance Areas

• 90 mg/kg/day divided every 12 hours is indicated for: 1
  • Community-acquired pneumonia in areas with >10% penicillin-resistant S. pneumoniae
  • Children <2 years old with pneumonia
  • Recent antibiotic exposure within the past 30 days
  • Children attending daycare
  • Severe infections requiring hospitalization

Group A Streptococcal Pharyngitis (Strep Throat/Scarlet Fever)

• 50-75 mg/kg/day divided every 12 hours for 10 days, not exceeding 1000 mg per dose 1
• The 10-day duration is critical to prevent acute rheumatic fever 1, 2
• Amoxicillin offers better palatability and adherence compared to penicillin V due to twice-daily dosing 1

Acute Otitis Media

• 45 mg/kg/day divided every 12 hours for children ≥2 years without risk factors 1
• 80-90 mg/kg/day divided every 12 hours for children <2 years, in daycare, or with recent antibiotic use 1

Special Populations

Infants <3 Months (12 Weeks)

• Maximum dose is 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 2
• This lower dosing is critical to prevent drug accumulation 2

Children with β-Lactamase-Producing Organisms

• Switch to amoxicillin-clavulanate (Augmentin) at 90 mg/kg/day of the amoxicillin component for coverage of β-lactamase-producing H. influenzae or Moraxella catarrhalis 1
• This is particularly important for children with incomplete H. influenzae type b vaccination or concurrent purulent acute otitis media 1

Critical Dosing Considerations

Maximum Daily Dose

• Never exceed 4000 mg/day regardless of weight 1
• For children >40 kg, use adult dosing: 500 mg every 12 hours for mild infections or 875 mg every 12 hours for severe infections 2

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
• Continue treatment for a minimum of 48-72 hours beyond symptom resolution 2

Clinical Monitoring

• Expect clinical improvement within 48-72 hours; if no improvement occurs, reevaluate for resistant organisms or alternative diagnoses 1
• Fever typically resolves within 24-48 hours for pneumococcal pneumonia, though cough may persist longer 1
• If deterioration or no improvement by 48-72 hours, consider atypical pathogens and potentially add a macrolide 1

Administration Guidance

Preparation and Storage

• Reconstitute powder with the specified amount of water per FDA label instructions 2
• Shake vigorously after adding water to ensure complete mixing 2
• Shake well before each use 2
• Refrigeration is preferable but not required; discard unused suspension after 14 days 2

Timing

• Administer at the start of a meal to minimize gastrointestinal intolerance 2
• For young children, place suspension directly on the tongue or mix with formula, milk, fruit juice, water, or cold drinks; administer immediately after mixing 2

Common Pitfalls to Avoid

• Do not use age-based dosing—always calculate based on weight in kg 1
• Do not underdose in severe infections—use 90 mg/kg/day, not 45 mg/kg/day, when indicated 1
• Do not prescribe 875 mg tablets to children with renal impairment (GFR <30 mL/min) 2
• Do not use amoxicillin alone for β-lactamase-producing organisms—switch to amoxicillin-clavulanate 1
• Do not stop treatment early for streptococcal infections—complete the full 10-day course 1, 2

Adverse Effects

• Most common: gastrointestinal disturbances (diarrhea, nausea, vomiting) 1
• Hypersensitivity reactions including rash and urticaria may occur 1
• For non-anaphylactic penicillin allergy, consider second- or third-generation cephalosporins (cefdinir, cefuroxime) 1