What is the recommended dose of amoxicillin (400mg/5ml) for a 10 kg pediatric patient?

Amoxicillin Dosing for a 10 kg Pediatric Patient

For a 10 kg child, administer 2.5 mL of amoxicillin 400mg/5mL suspension twice daily (every 12 hours) for mild to moderate respiratory infections, or 5 mL twice daily for severe infections or areas with high pneumococcal resistance. 1

Standard Dosing Algorithm

The recommended approach depends on infection severity and local resistance patterns:

Mild to Moderate Infections

• Standard dose: 45 mg/kg/day divided every 12 hours 1, 2
  • For a 10 kg child: 45 mg/kg/day = 450 mg/day total
  • Divided into 2 doses = 225 mg per dose
  • Using 400mg/5mL suspension: 2.5 mL twice daily 1

Severe Infections or High Pneumococcal Resistance

• High dose: 90 mg/kg/day divided every 12 hours 3, 1
  • For a 10 kg child: 90 mg/kg/day = 900 mg/day total
  • Divided into 2 doses = 450 mg per dose
  • Using 400mg/5mL suspension: 5 mL (approximately 5.6 mL for exact dosing) twice daily 1, 4

When to Use High-Dose Regimen

Use 90 mg/kg/day (5 mL twice daily) if any of the following apply: 1, 4

• Community-acquired pneumonia requiring treatment
• Recent antibiotic exposure within past 30 days
• Child attends daycare
• Geographic area with >10% penicillin-resistant Streptococcus pneumoniae
• Age <2 years with moderate to severe infection
• Suspected β-lactamase producing organisms (H. influenzae, M. catarrhalis)

Indication-Specific Guidance

Community-Acquired Pneumonia

• Preferred: 90 mg/kg/day in 2 doses (5 mL twice daily) for fully immunized children 3, 1
• This provides adequate coverage for penicillin-resistant S. pneumoniae 4
• Treatment duration: 10 days 1

Group A Streptococcal Infections

• 50-75 mg/kg/day in 2 doses 1
• For 10 kg child: 3-4 mL twice daily
• Treatment duration: 10 days mandatory to prevent rheumatic fever 2

Haemophilus influenzae (β-lactamase negative)

• 75-100 mg/kg/day in 3 doses 3
• If β-lactamase producing, switch to amoxicillin-clavulanate 3, 1

Critical Administration Details

• Administer at the start of meals to minimize gastrointestinal intolerance 2
• Shake suspension vigorously before each use 2
• Store reconstituted suspension in refrigerator (preferred but not required) 2
• Discard unused suspension after 14 days 2

Monitoring and Follow-Up

• Expect clinical improvement within 48-72 hours 1
• If no improvement by 48-72 hours, reevaluate for:
  • Atypical pathogens requiring macrolide addition 1
  • Resistant organisms
  • Alternative diagnosis
• Continue treatment minimum 48-72 hours beyond symptom resolution 2

Common Pitfalls to Avoid

Do not underdose based on adult maximum doses - The 10 kg child requires weight-based dosing even though 90 mg/kg/day (900 mg/day) may seem high relative to body size. Pediatric pharmacokinetics require higher mg/kg doses than adults to achieve therapeutic levels 5, 6

Do not use three-times-daily dosing - Twice-daily dosing at appropriate mg/kg doses provides equivalent or superior drug exposure compared to three-times-daily regimens and improves adherence 6, 7

Do not prescribe standard 40 mg/kg/day for pneumonia - This older dosing is inadequate for resistant S. pneumoniae, particularly with viral coinfection 5. Current guidelines mandate 45-90 mg/kg/day 3, 1

For β-lactamase producing organisms, amoxicillin alone will fail - Switch to amoxicillin-clavulanate 90 mg/kg/day (amoxicillin component) in 2 doses 3, 1