What is the recommended dosage of Amoxiclav (amoxicillin/clavulanic acid) for a 12kg child with no known allergies to penicillin or other medications and no severe renal impairment?

Amoxicillin-Clavulanate (Amoxiclav) Dosing for a 12kg Child

For a 12kg child, prescribe amoxicillin-clavulanate at 45 mg/kg/day of the amoxicillin component divided into 2 doses (270 mg twice daily) for mild to moderate infections, or 90 mg/kg/day divided into 2 doses (540 mg twice daily) for severe infections or suspected resistant pathogens. 1, 2

Standard Dosing Algorithm

Mild to Moderate Infections

• Standard dose: 45 mg/kg/day divided every 12 hours 1, 3
  • For a 12kg child: 270 mg twice daily (540 mg total daily dose)
  • This provides adequate coverage for most susceptible pathogens including Streptococcus pneumoniae, Haemophilus influenzae (non-β-lactamase producing), and Streptococcus pyogenes 1
  • Appropriate for uncomplicated respiratory tract infections, skin infections, and genitourinary infections 1

Severe Infections or High-Resistance Areas

• High-dose regimen: 90 mg/kg/day divided every 12 hours 1, 4, 2
  • For a 12kg child: 540 mg twice daily (1,080 mg total daily dose)
  • This dosing is specifically indicated for:
    • Community-acquired pneumonia in areas with >10% penicillin-resistant S. pneumoniae 1
    • Children <2 years old 1
    • Recent antibiotic exposure within the past 30 days 1
    • Children attending daycare 1
    • Severe infections requiring hospitalization 1
    • β-lactamase-producing organisms (H. influenzae, M. catarrhalis) 1, 5

Indication-Specific Dosing

Respiratory Tract Infections

• Mild to moderate pneumonia: 45 mg/kg/day in 2 doses (270 mg twice daily for 12kg child) 1, 4
• Severe pneumonia or resistant pathogens: 90 mg/kg/day in 2 doses (540 mg twice daily for 12kg child) 1, 4, 2
• The high-dose formulation (90 mg/kg/day) provides optimal coverage for penicillin-resistant Streptococcus pneumoniae and β-lactamase-producing organisms 1, 4

Acute Otitis Media

• Standard: 45 mg/kg/day in 2 doses for uncomplicated cases 1
• High-dose: 90 mg/kg/day in 2 doses for children with recent antibiotic use (within 4-6 weeks) to cover β-lactamase-producing organisms 1

Acute Bacterial Sinusitis

• Standard: 45 mg/kg/day in 2 doses for children ≥2 years without risk factors 1
• High-dose: 80-90 mg/kg/day in 2 doses for children <2 years, in daycare, or with recent antibiotic use 1

Critical Dosing Considerations

Maximum Daily Dose

• The absolute maximum limit for amoxicillin is 4,000 mg/day, regardless of weight 1, 2, 3
• For a 12kg child, this ceiling is not a concern with standard dosing regimens

Dosing Frequency

• Twice-daily dosing (every 12 hours) is preferred over three-times-daily dosing because it improves adherence and achieves superior pharmacokinetic profiles 4, 6, 7
• The FDA label supports both every 8-hour and every 12-hour dosing, but twice-daily administration is more practical 3

Administration

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

Treatment Duration and Monitoring

Duration of Therapy

• Most respiratory infections: 7-10 days 1
• Pneumonia specifically: 10 days 1, 4
• Group A Streptococcal infections: minimum 10 days to prevent acute rheumatic fever 3
• Continue treatment for at least 48-72 hours beyond symptom resolution 1, 3

Clinical Monitoring

• Children should show clinical improvement within 48-72 hours 1
• If no improvement occurs within this timeframe, reevaluation is necessary 1
• Consider atypical pathogens and potentially add a macrolide if the patient deteriorates or shows no improvement by 48-72 hours 1

Common Pitfalls and Caveats

Underdosing in Resistant Infections

• The traditional 40 mg/kg/day dosing is inadequate to effectively eradicate resistant Streptococcus pneumoniae, particularly during viral coinfection 8
• A dosing regimen of 75-90 mg/kg/day is recommended for acute otitis media and other infections where resistance is suspected 8

Viral Coinfection Impact

• Viral coinfection in acute otitis media reduces antibacterial efficacy of antibiotics 8
• Amoxicillin middle ear fluid penetration tends to be lower in children with viral infection 8
• This supports the use of higher doses (90 mg/kg/day) in clinical practice, especially during respiratory virus season

Adverse Effects

• The most common adverse effects include gastrointestinal disturbances (diarrhea, nausea, vomiting) 1
• Diarrhea is reported more frequently with amoxicillin-clavulanate compared to amoxicillin alone 5
• Rash, urticaria, and other hypersensitivity reactions may occur 1

Renal Impairment

• For children with severe renal impairment (GFR <30 mL/min), dose adjustment is required 3
• However, for a 12kg child with no known renal impairment, standard dosing applies