Is 80 mg/kg/dose of Co-amoxiclav (amoxicillin/clavulanic acid) a high dose for a 5-year-old child weighing 18 kg with an Upper Respiratory Tract Infection (URTI)?

80 mg/kg/dose Co-Amoxiclav is Dangerously Low and Inappropriate for a 5-Year-Old with URTI

This dose of 80 mg/kg/dose is grossly inadequate and represents a critical dosing error that will lead to treatment failure and promote antimicrobial resistance. 1

Critical Dosing Error Analysis

What This Child Should Actually Receive

For a 5-year-old child weighing 18 kg, the standard recommended dose is 5 ml of 125/31 suspension three times daily, which provides approximately 125 mg of amoxicillin per dose (total daily dose ~375 mg or ~21 mg/kg/day). 2

• If high-dose therapy is indicated (for resistant organisms or severe infection): 90 mg/kg/day divided into 2 doses = 810 mg twice daily (1620 mg/day total). 1
• For moderate infections: 45 mg/kg/day in divided doses = approximately 405 mg twice daily or 270 mg three times daily. 1, 3

Why 80 mg/kg/dose is Wrong

An 80 mg/kg single dose would equal 1440 mg per dose for this 18 kg child. 1

• This appears to be a confusion between total daily dose and per-dose amount. 1
• The question likely means "80 mg/kg/day" not "per dose," but even this interpretation is problematic for standard URTI treatment. 1
• If truly given as 80 mg/kg per dose three times daily, this would equal 4320 mg/day—a massive overdose far exceeding any guideline recommendation. 1, 3

The Fundamental Problem: Most URTIs Don't Need Antibiotics

Before prescribing any antibiotic for URTI, confirm the child actually has bacterial infection requiring treatment. 1

• The vast majority of URTIs are viral and receive no benefit from antibiotics. 1
• Antibiotics should only be prescribed if the child meets criteria for acute bacterial rhinosinusitis: persistent symptoms >10 days without improvement, severe symptoms, or "double sickening" pattern. 1

Correct Dosing Algorithm for This Child

Step 1: Confirm Bacterial Infection Indication

• Does the child have symptoms >10 days without improvement? 1
• Are there severe symptoms (high fever ≥39°C, purulent nasal discharge for ≥3 consecutive days)? 1
• Is there a "double sickening" pattern (worsening after initial improvement)? 1

If NO to all above: Do not prescribe antibiotics. 1

Step 2: If Antibiotics Are Indicated, Choose Appropriate Dose

For standard bacterial URTI (if truly indicated):

• 5 ml of 125/31 suspension three times daily for ages 1-6 years. 2
• This provides ~21 mg/kg/day of amoxicillin component. 2

For high-dose therapy (if child has risk factors):

• Risk factors include: age <2 years, daycare attendance, recent antibiotic use within 30 days, moderate-to-severe illness. 1
• High-dose regimen: 90 mg/kg/day of amoxicillin component in 2 divided doses (45 mg/kg per dose twice daily). 1
• For this 18 kg child: 810 mg twice daily. 1

For IV therapy (severe infections only):

• 30 mg/kg three times daily IV. 2
• For this 18 kg child: 540 mg IV three times daily. 2

Clinical Consequences of Incorrect Dosing

Subtherapeutic dosing leads to:

• Treatment failure with even susceptible organisms due to inadequate serum and tissue concentrations. 1
• Promotion of antimicrobial resistance. 1
• Increased risk of complications from inadequately treated bacterial infection. 1

Excessive dosing (if 80 mg/kg per dose is given three times daily) risks:

• Severe gastrointestinal adverse effects (diarrhea, nausea, vomiting). 3, 4
• Potential hepatotoxicity with clavulanate component. 3
• Unnecessary antibiotic exposure promoting resistance. 1

Common Pitfalls to Avoid

• Verify suspension concentration (125/31 vs 250/62) before calculating volume to prevent dosing errors. 1, 5
• Do not confuse total daily dose with per-dose amount—this is the most likely error in this scenario. 1
• Do not prescribe antibiotics for viral URTIs—this increases adverse effects without benefit and promotes resistance. 1
• Do not use adult formulations for children, as this leads to dosing errors. 5

Evidence Quality Note

The dosing recommendations come from multiple consistent guidelines including British Infection Society/British Thoracic Society guidelines 2 and American Academy of Pediatrics recommendations 1, with supporting FDA labeling 3. The evidence strongly supports that 80 mg/kg as a single dose represents either a calculation error or misunderstanding of dosing conventions. 1