What is the recommended dose of amoxicillin (amoxicillin) suspension for a pediatric patient weighing 23.1 kg?

Amoxicillin Suspension Dosing for a 23.1 kg Pediatric Patient

For a child weighing 23.1 kg, the recommended amoxicillin dose is 45 mg/kg/day divided every 12 hours (approximately 520 mg twice daily or 10.4 mL of 250 mg/5 mL suspension twice daily) for mild to moderate respiratory tract infections, or 90 mg/kg/day divided every 12 hours (approximately 1040 mg twice daily or 20.8 mL of 250 mg/5 mL suspension twice daily) for severe infections or areas with high pneumococcal resistance. 1

Weight-Based Dosing Algorithm

This patient weighing 23.1 kg falls into the >15 kg to ≤40 kg weight category for standard dosing recommendations. 2

For Mild to Moderate Infections:

• Standard dose: 45 mg/kg/day divided every 12 hours 1, 2
• For this 23.1 kg patient: 23.1 kg × 45 mg/kg/day = 1,040 mg/day total
• Practical dosing: 520 mg (10.4 mL of 250 mg/5 mL suspension) twice daily 1
• This regimen provides adequate coverage for most susceptible pathogens including Streptococcus pneumoniae, Haemophilus influenzae (non-β-lactamase producing), and Streptococcus pyogenes 1

For Severe Infections or High-Resistance Areas:

• High-dose regimen: 90 mg/kg/day divided every 12 hours 1, 2
• For this 23.1 kg patient: 23.1 kg × 90 mg/kg/day = 2,078 mg/day total
• Practical dosing: 1,040 mg (20.8 mL of 250 mg/5 mL suspension) twice daily 1
• The high-dose regimen is specifically indicated when:
  • Community-acquired pneumonia in areas with >10% penicillin-resistant S. pneumoniae 1
  • Child <2 years old 1
  • Recent antibiotic exposure within the past 30 days 1
  • Child attending daycare 1
  • Severe infections requiring hospitalization 1

Indication-Specific Dosing

Community-Acquired Pneumonia:

• Mild to moderate (outpatient): 45 mg/kg/day divided every 12 hours 1
• Severe or high-resistance: 90 mg/kg/day divided every 12 hours 1

Acute Bacterial Sinusitis:

• Without risk factors: 45 mg/kg/day divided every 12 hours 1
• With risk factors (age <2 years, daycare, recent antibiotics): 80-90 mg/kg/day divided every 12 hours 1

Group A Streptococcal Infections (Pharyngitis/Scarlet Fever):

• Recommended dose: 50-75 mg/kg/day divided into 2 doses for 10 days 1
• For this 23.1 kg patient: approximately 580-865 mg twice daily 1
• Maximum dose per intake should not exceed 1000 mg 1

Skin and Soft Tissue Infections:

• Mild to moderate: 25 mg/kg/day divided every 12 hours 2
• Severe: 45 mg/kg/day divided every 12 hours 2

Critical Dosing Considerations

• Maximum daily dose: The total daily dose should not exceed 4000 mg/day regardless of weight 1
• Treatment duration: Most respiratory infections require 7-10 days of treatment, with pneumonia specifically requiring 10 days 1
• Clinical improvement timeline: Children on appropriate therapy should demonstrate clinical improvement within 48-72 hours; if no improvement occurs, reevaluation and further investigation are necessary 1

When to Use Amoxicillin-Clavulanate Instead

Switch to amoxicillin-clavulanate (Augmentin) at 90 mg/kg/day of the amoxicillin component if: 1

• β-lactamase-producing organisms suspected (H. influenzae, M. catarrhalis) 1
• Recent antibiotic exposure within the past 4-6 weeks 1
• Incomplete H. influenzae type b vaccination 1
• Concurrent purulent acute otitis media 1

Administration Guidelines

• Administer at the start of meals to minimize gastrointestinal intolerance 2
• Shake suspension well before each use 2
• Use calibrated oral dosing device for accurate measurement 3
• Refrigeration is preferable but not required for reconstituted suspension 2
• Discard unused suspension after 14 days of reconstitution 2

Common Pitfalls to Avoid

• Do not underdose severe infections: Always use 90 mg/kg/day for life-threatening infections, empyema, or documented resistant pneumococcus 1
• Do not round up to the next weight category prematurely: A child weighing 23.1 kg remains in the >15 to ≤40 kg bracket and should not receive dosing for >40 kg 3
• Do not use plain amoxicillin for β-lactamase producers: If H. influenzae or M. catarrhalis with β-lactamase production is suspected, amoxicillin-clavulanate is essential for clinical success 1
• Complete the full course: Even if symptoms improve before completion, finish the prescribed duration to prevent treatment failure and resistance 1

Monitoring and Follow-Up

• Expect fever resolution within 24-48 hours for pneumococcal pneumonia, though cough may persist longer 1
• If no improvement by 48-72 hours: Consider atypical pathogens and potentially add or switch to a macrolide 1
• For Group A Streptococcal infections: Patients stop being contagious after 24 hours of antibiotic therapy 1