A 3‑year‑old child (~12–15 kg) ingested 25 mL of amoxicillin‑clavulanate suspension (400 mg amoxicillin/mL). What is the appropriate emergency management?

Emergency Management of Amoxicillin-Clavulanate Overdose in a 3-Year-Old

This ingestion represents approximately 10,000 mg of amoxicillin (667–833 mg/kg for a 12–15 kg child), which is roughly 10–20 times the maximum recommended daily dose, but amoxicillin overdose rarely causes serious toxicity and supportive care at home with close monitoring is appropriate for most cases.

Immediate Assessment and Risk Stratification

Calculate the exact dose ingested:

• 25 mL × 400 mg/mL = 10,000 mg of amoxicillin total
• For a 12 kg child: 833 mg/kg
• For a 15 kg child: 667 mg/kg
• This is 7–9 times the high-dose therapeutic regimen of 90 mg/kg/day 1

Expected toxicity profile:

• Amoxicillin has a wide therapeutic index; serum levels increase linearly with dose, and the difference in adverse effects between lower and higher doses is generally negligible 1
• The most common adverse effects are gastrointestinal: diarrhea, nausea, vomiting, and abdominal discomfort 1, 2
• Serious toxicity (renal crystalluria, seizures, or hepatotoxicity) is extremely rare even with massive overdoses 3

Immediate Management (First 2 Hours)

Do NOT induce vomiting or administer activated charcoal if more than 1 hour has elapsed since ingestion, as amoxicillin is rapidly absorbed with peak concentrations occurring 1.3–1.4 hours after oral administration 4

If the child presents within 1 hour of ingestion:

• Consider activated charcoal (1 g/kg, maximum 50 g) only if the child is alert and can protect their airway
• This is optional, not mandatory, given the low toxicity profile

Monitor for immediate symptoms:

• Nausea and vomiting (most likely within 2–4 hours)
• Abdominal cramping
• Early-onset diarrhea

Outpatient Monitoring Protocol (Next 24–48 Hours)

Instruct caregivers to monitor for:

• Gastrointestinal symptoms: Diarrhea (occurs in approximately 25% of children on therapeutic doses and may be more frequent with overdose), nausea, vomiting 1
• Fluid status: Ensure adequate oral hydration; if diarrhea develops, use oral rehydration solution
• Rash or urticaria: Hypersensitivity reactions may occur but are not dose-dependent 2
• Behavioral changes: Irritability or lethargy (uncommon but warrant reassessment)

Provide specific return precautions:

• Persistent vomiting (>3 episodes) preventing oral hydration
• Severe or bloody diarrhea
• Decreased urine output or dark urine (crystalluria risk, though rare)
• Rash with fever or mucosal involvement (Stevens-Johnson syndrome, extremely rare)
• Altered mental status or seizure activity (exceptionally rare)

Laboratory Monitoring

Routine laboratory testing is NOT indicated for uncomplicated amoxicillin overdose in a previously healthy child 1, 5

Consider baseline and 48-hour follow-up labs only if:

• The child has pre-existing renal impairment (amoxicillin and clavulanate are renally eliminated) 1
• Persistent vomiting or diarrhea leads to dehydration
• Any signs of hepatotoxicity develop (jaundice, right upper quadrant pain)—though cholestatic hepatitis from amoxicillin-clavulanate typically occurs after 13.9 days of therapeutic dosing, not acute overdose 3

If labs are obtained, check:

• Serum creatinine and BUN (renal function)
• Urinalysis (for crystalluria, though rare)
• Liver enzymes (ALT, AST, alkaline phosphatase, bilirubin) only if clinical suspicion of hepatotoxicity 3

Supportive Care Measures

Hydration:

• Encourage oral fluids (water, oral rehydration solution) to maintain urine output and minimize crystalluria risk
• Target urine output >1 mL/kg/hour

Symptomatic treatment:

• Ondansetron 0.15 mg/kg (maximum 8 mg) for persistent nausea/vomiting
• Probiotics may reduce antibiotic-associated diarrhea, though evidence is mixed

Avoid:

• Antidiarrheal agents (loperamide) in young children, as they may prolong toxin exposure

When to Refer to Emergency Department

Immediate ED referral if:

• The child is symptomatic at presentation with altered mental status, seizures, or respiratory distress (extremely unlikely but mandates evaluation)
• Pre-existing renal disease or known hypersensitivity to penicillins
• Inability to tolerate oral fluids due to persistent vomiting

Delayed ED referral (within 24–48 hours) if:

• Signs of dehydration develop (dry mucous membranes, decreased urine output, lethargy)
• Severe or bloody diarrhea
• Jaundice or right upper quadrant pain (hepatotoxicity, though timing would be atypical) 3

Common Pitfalls to Avoid

• Over-intervention: Amoxicillin overdose is not a medical emergency in most cases; avoid unnecessary hospitalization or invasive procedures 1, 5
• Delayed recognition of dehydration: Gastrointestinal losses from diarrhea and vomiting can accumulate quickly in young children; emphasize hydration to caregivers
• Misattributing rash to overdose: Amoxicillin rash is common (occurs in up to 10% of children on therapeutic doses) and is not dose-dependent; distinguish benign maculopapular rash from serious hypersensitivity reactions 2
• Unnecessary antibiotic discontinuation: If the child was being treated for a bacterial infection, the overdose does not necessitate stopping therapy once symptoms resolve; resume appropriate dosing after 24–48 hours if indicated

Expected Clinical Course

• Most children remain asymptomatic or develop mild gastrointestinal symptoms within 2–6 hours 1, 4
• Diarrhea typically resolves within 24–48 hours after the overdose
• Complete recovery is expected in >99% of cases with supportive care alone 5, 3