What is the appropriate amoxicillin‑clavulanic acid (amoxyclav) syrup dose for a child based on body weight and infection severity?

Amoxicillin-Clavulanate (Amoxyclav) Syrup Body Weight Dosing for Children

For most pediatric infections requiring amoxicillin-clavulanate, use the high-dose regimen of 90 mg/kg/day of amoxicillin + 6.4 mg/kg/day clavulanate divided into two doses (every 12 hours), with a maximum of 4 g/day amoxicillin. 1

High-Dose Regimen (Preferred for Most Infections)

The high-dose formulation provides a 14:1 ratio of amoxicillin to clavulanate, which reduces diarrhea incidence while maintaining superior efficacy against resistant organisms. 1

Standard Dosing Calculation

• Dose: 90 mg/kg/day amoxicillin component divided every 12 hours 1
• Maximum single dose: 2,000 mg amoxicillin per administration, regardless of weight 1, 2
• Maximum daily dose: 4,000 mg amoxicillin per day 1, 3

Practical Example

For a 20 kg child:

• Total daily dose = 20 kg × 90 mg/kg = 1,800 mg/day
• Per dose = 900 mg every 12 hours
• Using 250 mg/5 mL suspension = 18 mL twice daily 1

When High-Dose Therapy Is Mandatory

Use 90 mg/kg/day if ANY of the following risk factors are present: 1, 2

• Age < 2 years 1, 3
• Daycare attendance 1, 3
• Antibiotic use within the preceding 30 days 1, 3
• Incomplete Hib vaccination (< 3 doses) 1
• Geographic area where > 10% of S. pneumoniae are penicillin-resistant 1, 3
• Moderate to severe illness at presentation 1
• Concurrent purulent acute otitis media 1
• Prior treatment failure with amoxicillin alone 1

Standard-Dose Regimen (Limited Use Only)

• Dose: 45 mg/kg/day amoxicillin + 6.4 mg/kg/day clavulanate divided every 12 hours 1
• Reserved exclusively for: Uncomplicated infections in children ≥ 2 years without any identified risk factors 1, 3
• Critical warning: Using standard doses when high-dose therapy is indicated leads to treatment failure against resistant organisms 2

Infection-Specific Dosing

Acute Otitis Media

• 90 mg/kg/day in two divided doses for 10 days 1
• Predicted clinical efficacy of 90-92% against penicillin-resistant S. pneumoniae 1, 2
• Children < 2 years must receive the high-dose formulation 1, 2

Community-Acquired Pneumonia

• Children < 5 years: 90 mg/kg/day in two divided doses for 10 days 1, 3
• Children ≥ 5 years: 90 mg/kg/day in two divided doses (maximum 4 g/day) for 10 days 1, 3
• If incomplete Hib vaccination or concurrent purulent otitis media: 80-90 mg/kg/day 1, 2

Acute Bacterial Rhinosinusitis

• 90 mg/kg/day in two divided doses for 10-14 days 1, 2
• Strongly recommended as first-line therapy 1, 2

Skin and Soft-Tissue Infections

• Children < 1 year: 0.266 mL/kg of 125/31 mg/mL suspension three times daily 1
• Duration: 7-10 days, extendable to 14 days based on clinical response 1
• Severe infections: dose may be doubled 1

Age-Based Dosing (For Mild Infections Only)

These age-based doses deliver substantially lower amoxicillin exposure than the high-dose regimen and should be reserved exclusively for mild infections without any risk factors: 1

Age	Suspension & Volume (TID)
< 1 yr (1-12 mo)	2.5 mL of 125/31 mg/mL [1,2]
1-6 yr	5 mL of 125/31 mg/mL [1,2]
7-12 yr	5 mL of 250/62 mg/mL [1,2]
12-18 yr	1 tablet (250/125 mg) [1,2]

Intravenous Dosing for Severe Infections

• 30 mg/kg every 8 hours (TID) IV for all pediatric ages 1, 2
• Switch to oral formulation as soon as clinically appropriate 1

Treatment Duration and Monitoring

• Standard course: 10 days for most pediatric infections 1, 3, 2
• Expected clinical improvement: Within 48-72 hours of therapy initiation 1, 3, 2
• If no improvement or worsening after 72 hours: Re-evaluate diagnosis, consider atypical pathogens, assess for complications, or change antibiotics 1, 3, 2
• Continue for an additional 7 days once the child is free of signs and symptoms 2

Critical Dosing Considerations and Common Pitfalls

Suspension Verification

Always confirm the concentration (125/31 mg/mL vs 250/62 mg/mL) before calculating volume to avoid dosing errors. 1, 2

Underdosing Consequences

• Using age-based dosing when high-dose therapy is indicated leads to treatment failure against resistant organisms 1, 2
• Subtherapeutic exposure fails to achieve adequate serum/tissue levels and promotes resistance 1
• Incomplete courses increase the risk of treatment failure and antimicrobial resistance 1

Renal Impairment

• Prolong the dosing interval according to creatinine clearance to avoid drug accumulation 1, 2
• Both amoxicillin and clavulanate are renally eliminated; significant dose reduction is required in children with reduced renal function 1, 2

Adverse Effects

• Diarrhea occurs in ~25% of treated children vs 15% with placebo 1, 2
• Nausea, vomiting, and diaper dermatitis occur in ~51% vs 35% with placebo 1, 2
• The 14:1 amoxicillin-to-clavulanate formulation reduces diarrhea incidence compared with other preparations 1, 2

Alternatives for Penicillin Allergy

Non-Type I (Non-Anaphylactic) Allergy

• Clindamycin + third-generation oral cephalosporin 1, 3
• Second- or third-generation cephalosporins (cefdinir, cefuroxime) are safe alternatives 3

Type I (Anaphylaxis) Allergy

Clarithromycin dosing: 1

• < 1 yr: 7.5 mg/kg BID
• 1-2 yr: 62.5 mg BID
• 3-6 yr: 125 mg BID
• 7-9 yr: 187.5 mg BID
• ≥ 10 yr: 250 mg BID

Alternative: Clindamycin 10-20 mg/kg/day in three doses 1, 3

Special Populations

Children Weighing ≥ 40 kg

• Dose as adults using standard adult formulations and dosing regimens 3

Infants < 3 Months

• Safety and efficacy data are limited for infants younger than 3 months 2
• For suspected serious bacterial infections, intravenous regimens (ampicillin + gentamicin or cefotaxime) are preferred 2
• If oral amoxicillin-clavulanate is deemed necessary, specialist consultation should be obtained 2