Amoxyclav Dosing for 18 kg Pediatric Patient
For an 18 kg child, the appropriate dose of Amoxyclav is 5 mL of 250/62 suspension twice daily (providing 90 mg/kg/day of amoxicillin component), which is the high-dose regimen recommended for most pediatric infections. 1
Weight-Based Calculation
- For this 18 kg patient, the high-dose regimen calculates to 1620 mg/day of amoxicillin (90 mg/kg/day × 18 kg = 1620 mg/day), divided into 2 doses of 810 mg each 1
- Using the 250/62 suspension (250 mg amoxicillin per 5 mL), this equals approximately 16 mL per day total, or 8 mL twice daily 1
- However, practical age-based dosing guidelines recommend 5 mL of 250/62 suspension twice daily for children in the 7-12 year age range, which provides approximately 500 mg per dose 1, 2
Why High-Dose Therapy is Preferred
The high-dose formulation (90 mg/kg/day with 6.4 mg/kg/day clavulanate in 2 divided doses) is indicated for children with specific risk factors: 1
Age less than 2 years 1
Daycare attendance 1
Recent antibiotic use within the previous 30 days 1
Incomplete Haemophilus influenzae type b vaccination 1
Geographic areas with high prevalence of penicillin-resistant Streptococcus pneumoniae (>10%) 1
Moderate to severe illness 1
The high-dose regimen achieves middle ear fluid concentrations adequate to overcome penicillin-resistant S. pneumoniae and provides coverage for β-lactamase-producing organisms 1
Using standard doses when high-dose therapy is indicated leads to treatment failure with resistant organisms 1
Practical Dosing Recommendation
The dose you mentioned (228.5 mg BD) appears to be significantly underdosed for an 18 kg child. 1
- The correct high-dose regimen should provide approximately 810 mg of amoxicillin per dose (twice daily), not 228.5 mg 1
- This represents less than 30% of the recommended dose and will fail to achieve adequate serum and tissue concentrations 1
- Subtherapeutic dosing promotes antimicrobial resistance and increases risk of treatment failure 1
Treatment Duration and Monitoring
- Continue treatment for 10 days for most pediatric infections, including respiratory tract infections and acute otitis media 1
- Clinical improvement should be evident within 48-72 hours of starting therapy 1
- If no improvement or worsening occurs after 72 hours, reevaluate the diagnosis and consider switching antibiotics or further investigation 1
Administration Considerations
- Administer at the start of meals to minimize gastrointestinal intolerance and enhance absorption of clavulanate 3
- The medication can be given with or without food, though administration with meals may improve tolerability 2
- Shake oral suspension well before using 4
Common Pitfalls to Avoid
- Never use two 250/125 tablets to substitute for one 500/125 tablet, as both contain the same amount of clavulanic acid (125 mg) 3
- Verify the suspension concentration (125/31 vs 250/62) before calculating volume to avoid dosing errors 1
- The 14:1 ratio formulation (90/6.4 mg/kg/day) causes less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy 1
- Most common adverse effects include diarrhea, nausea, vomiting, and rash 1