Co-Amoxiclav Dosing for a 3-Year-Old, 15kg Patient
For a 3-year-old female weighing 15 kg, administer 5 mL of the 125/31 mg/5mL suspension three times daily for most infections, or use the high-dose regimen of 10.7 mL twice daily (90 mg/kg/day of amoxicillin component) for severe infections or when resistant organisms are suspected. 1
Standard Dosing Regimen
For children aged 1-6 years, the recommended dose is 5 mL of 125/31 suspension three times daily, which provides approximately 125 mg of amoxicillin per dose (total 375 mg/day or 25 mg/kg/day for this 15 kg child). 1
This standard regimen is appropriate for mild to moderate infections including upper respiratory tract infections, skin infections, and uncomplicated urinary tract infections. 1
The 475 mg/5mL concentration you mentioned appears to be a high-dose formulation; verify the actual concentration on the bottle before calculating the volume, as dosing errors commonly occur when prescribers confuse different suspension strengths. 1
High-Dose Regimen for Severe Infections
When high-dose therapy is indicated (90 mg/kg/day), calculate as follows for this 15 kg child:
15 kg × 90 mg/kg/day = 1,350 mg/day of amoxicillin component, divided into 2 doses = 675 mg per dose. 1
If using a 600 mg/5mL high-dose formulation (14:1 ratio), this would be approximately 5.6 mL twice daily. 2, 3
If using the standard 125 mg/5mL suspension to achieve high-dose therapy, you would need 27 mL twice daily (which is impractical, making the high-dose formulation essential). 1
Indications for High-Dose Regimen
Use the 90 mg/kg/day regimen when any of these risk factors are present:
Age less than 2 years (this patient is 3 years old, so this doesn't apply). 1
Recent antibiotic use within the past 4-6 weeks. 1
Daycare attendance. 1
Incomplete Haemophilus influenzae type b vaccination (less than 3 doses). 1
Geographic area with high pneumococcal resistance (>10% penicillin-resistant S. pneumoniae). 1
Moderate to severe illness presentation. 1
Concurrent purulent acute otitis media with pneumonia. 1
Treatment Duration and Monitoring
Continue treatment for 7-10 days for most respiratory infections, with pneumonia specifically requiring 10 days. 4, 1
Clinical improvement should be evident within 48-72 hours; if no improvement or worsening occurs, reevaluate the diagnosis and consider resistant organisms or alternative diagnoses. 4, 1
Complete the full course even if symptoms improve before completion. 4
Critical Dosing Considerations
Always verify the suspension concentration before dispensing (125/31 vs 250/62 vs 600/42.9 mg/5mL formulations exist), as this is the most common source of dosing errors. 1
The high-dose 14:1 ratio formulation (90 mg/kg/day amoxicillin with 6.4 mg/kg/day clavulanate) causes less diarrhea than standard formulations while maintaining superior efficacy against resistant organisms. 1, 2
Subtherapeutic dosing leads to treatment failure and promotes antimicrobial resistance; never use doses lower than recommended guidelines. 1
Take at the start of meals to minimize gastrointestinal intolerance. 5
Shake the suspension well before each use and refrigerate after reconstitution (though not required). 5
Discard any unused suspension after 14 days. 5
Common Pitfalls to Avoid
Do not prescribe antibiotics for viral upper respiratory tract infections, which constitute the vast majority of URTIs in children and do not benefit from antibiotics. 1
Ensure the diagnosis warrants antibiotics before prescribing (e.g., persistent symptoms >10 days, severe symptoms, or "double sickening" pattern for bacterial rhinosinusitis). 1
Using standard doses when high-dose therapy is indicated leads to inevitable treatment failure with resistant organisms. 1
The maximum single dose is 2 grams regardless of weight. 1