What is the typical dosage of amoxicillin (amoxicillin-clavulanic acid) for a 12-year-old child?

Amoxicillin-Clavulanic Acid Dosing for a 12-Year-Old

For a 12-year-old child, the standard dose of amoxicillin-clavulanic acid is 90 mg/kg/day of the amoxicillin component divided into 2 doses (maximum 4 g/day), which translates to approximately 45 mg/kg per dose given twice daily. 1

Standard Dosing Recommendations

For Most Infections

• The typical dose is 90 mg/kg/day of amoxicillin divided into 2 doses 1
• This can also be given as 45 mg/kg/day divided into 3 doses, though twice-daily dosing is now preferred for convenience and comparable efficacy 2, 3
• Maximum daily dose should not exceed 4 g of amoxicillin 1

Weight-Based Calculation

For a typical 12-year-old weighing approximately 40 kg:

• Total daily dose: 3,600 mg amoxicillin (90 mg/kg × 40 kg)
• Per dose: 1,800 mg twice daily or approximately 1,200 mg three times daily
• The clavulanic acid component is typically in a 4:1 or higher ratio with amoxicillin 4, 5

Indication-Specific Considerations

Respiratory Tract Infections (Pneumonia, Sinusitis)

• High-dose amoxicillin-clavulanate at 90 mg/kg/day in 2 divided doses is recommended when resistant Streptococcus pneumoniae is suspected 1, 5
• This dosing provides adequate coverage for penicillin-intermediate and some penicillin-resistant strains 5

Acute Otitis Media

• Standard dose: 90/6.4 mg/kg/day (amoxicillin/clavulanate) in 2 divided doses 5
• The high-dose formulation (90 mg/kg/day) is particularly important for recurrent or persistent cases where resistant pathogens are likely 5

Urinary Tract Infections

• 40 mg/kg/day divided into 2 doses for 5 days for acute infections 6
• For recurrent infections, initial treatment at 40 mg/kg/day followed by long-term prophylaxis at 20 mg/kg once daily may be considered 6

Dosing Frequency

Twice-daily dosing is as effective as three-times-daily dosing and improves compliance 3

• Clinical cure rates, recurrence rates, and adverse event profiles are comparable between once/twice daily and three-times daily regimens 3
• Twice-daily dosing may reduce gastrointestinal side effects compared to three-times-daily dosing 5, 3

Important Clinical Considerations

Common Pitfalls to Avoid

• Do not underdose: Using conventional doses (40-45 mg/kg/day) may be inadequate for resistant organisms, particularly in respiratory infections 5
• Ensure proper ratio: The amoxicillin-clavulanate formulation matters—high-dose formulations use a higher amoxicillin-to-clavulanate ratio (14:1 or 16:1) to minimize clavulanate-related diarrhea while maximizing amoxicillin exposure 5

Tolerability

• Most common adverse effects are mild gastrointestinal disturbances (diarrhea, nausea) 4, 5, 6
• Diarrhea occurs less frequently with twice-daily versus three-times-daily dosing 5
• If gastrointestinal symptoms occur, switching from 12-hour to 8-hour intervals may help 6
• Overall adverse event rates are low (approximately 3.6% in large postmarketing studies) 5

Duration of Therapy

• 5-7 days is typically adequate for most infections 4, 6
• Specific infections may require longer courses (e.g., complicated infections, osteomyelitis)