Amoxicillin Dosing for a 10-Year-Old Child with Medial Canthus Swelling
For a 10-year-old child weighing 20kg with swelling in the medial canthus, the appropriate amoxicillin dosage is 40 mg/kg/day divided into 2-3 doses, which equals 800 mg per day (400 mg twice daily or approximately 267 mg three times daily). 1, 2
Dosing Calculation and Rationale
The swelling in the medial canthus likely represents periorbital cellulitis or preseptal cellulitis, which requires prompt antibiotic treatment to prevent spread of infection to orbital tissues or intracranial structures.
For pediatric patients weighing less than 40 kg, the FDA-approved dosing guidelines recommend:
- For mild to moderate infections: 25 mg/kg/day divided every 12 hours or 20 mg/kg/day divided every 8 hours 2
- For severe infections: 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours 2
Given the location of the infection near the eye, which poses risk for serious complications:
- Standard dose: 40 mg/kg/day is appropriate 1
- For a 20 kg child: 40 mg/kg/day × 20 kg = 800 mg/day
- Administration options:
- 400 mg twice daily (every 12 hours)
- 267 mg three times daily (every 8 hours)
Administration Considerations
- Administer at the start of a meal to minimize gastrointestinal intolerance 2
- Treatment duration should be 7-10 days for infections near the eye to ensure complete eradication 3, 1
- If using amoxicillin suspension:
- Shake well before each use
- Measure doses accurately using the provided measuring device
- Store reconstituted suspension in refrigerator (preferable but not required) 2
Monitoring and Follow-up
- Assess response to treatment within 48-72 hours
- If no improvement occurs after 72 hours, consider:
- Changing to amoxicillin-clavulanate (40 mg/kg/day of amoxicillin component)
- Obtaining cultures if possible
- Referral to ophthalmology if periorbital swelling worsens
Potential Adverse Effects
Common side effects to monitor for include:
- Gastrointestinal: diarrhea, nausea, vomiting
- Skin: rash (may indicate allergic reaction)
- Oral: thrush (candidiasis)
Important Considerations
- If the child has a history of penicillin allergy, alternative antibiotics such as clarithromycin or azithromycin should be considered 1
- If the infection appears severe (significant swelling, erythema, fever, or systemic symptoms), consider immediate referral for possible intravenous antibiotics and imaging
- Ensure adequate hydration during treatment
This dosing recommendation balances the need for effective treatment of an infection in a sensitive area while avoiding excessive antibiotic exposure in a pediatric patient.