Yes, the 125 mg/5 mL amoxicillin suspension is appropriate for your 42-lb child
For a 42-lb (19 kg) child, the 125 mg/5 mL suspension is an acceptable formulation, though you'll need to give a larger volume per dose compared to the 250 mg/5 mL concentration. The specific dose and frequency depend on the infection being treated.
Dosing Based on Infection Type
For Mild to Moderate Ear, Nose, Throat, Skin, or Urinary Tract Infections
- Standard dose: 20-25 mg/kg/day divided every 8-12 hours 11
- For your 19 kg child: approximately 380-475 mg/day total
- Using 125 mg/5 mL suspension: Give 7.5-10 mL every 12 hours OR 5-6.5 mL every 8 hours
For Severe Infections or Lower Respiratory Tract Infections
- High dose: 40-45 mg/kg/day divided every 8-12 hours 11
- For your 19 kg child: approximately 760-855 mg/day total
- Using 125 mg/5 mL suspension: Give 15-17 mL every 12 hours OR 10-11 mL every 8 hours
For Suspected Pneumococcal Infections (Pneumonia, Sinusitis, Otitis Media with Resistance Risk)
- High dose: 80-90 mg/kg/day divided every 12 hours 2223
- For your 19 kg child: approximately 1520-1710 mg/day total
- Using 125 mg/5 mL suspension: Give 30-34 mL every 12 hours
Important Practical Considerations
The 125 mg/5 mL concentration requires larger volumes for high-dose therapy. For a 19 kg child needing high-dose amoxicillin (80-90 mg/kg/day), you would need to give 30-34 mL twice daily, which is quite a large volume for a child to take. The 250 mg/5 mL concentration would be more practical as it would require only 15-17 mL per dose 11.
When High-Dose Amoxicillin is Recommended
High-dose therapy (80-90 mg/kg/day) should be used for 34:
- Children under 2 years old
- Recent antibiotic use within the past 30 days
- Daycare attendance
- Severe symptoms at presentation
- Geographic areas with >10% pneumococcal penicillin resistance
Administration Tips
- Shake the suspension vigorously before each dose 11
- Can be mixed with formula, milk, fruit juice, water, or cold drinks if needed 1
- Must be taken immediately after mixing with liquids
- Store at room temperature (refrigeration preferred but not required) 11
- Discard any unused suspension after 14 days 11
Duration of Treatment
- Typical duration: 5-10 days for most infections 11
- Streptococcal infections: minimum 10 days to prevent rheumatic fever 11
- Continue for 48-72 hours after symptoms resolve 11
Bottom line: While the 125 mg/5 mL formulation works, consider asking your pharmacist if the 250 mg/5 mL concentration is available, as it would require half the volume per dose and be easier for your child to take, especially if high-dose therapy is needed.