What are the management steps for amoxicillin (amoxicillin) toxicity?

Management of Amoxicillin Toxicity

Discontinue amoxicillin immediately and provide supportive care with symptom-directed treatment, as the vast majority of amoxicillin overdoses are not associated with significant clinical toxicity. 1

Immediate Assessment and Discontinuation

• Stop amoxicillin administration immediately upon recognition of toxicity or overdose 1
• Assess the ingested dose: overdoses less than 250 mg/kg are typically not associated with significant clinical symptoms in pediatric patients 1
• Evaluate for signs of serious toxicity including renal dysfunction, crystalluria, allergic reactions, or hemolytic complications 1, 2, 3

Supportive Management

Fluid Management and Renal Protection

• Maintain adequate fluid intake and ensure diuresis to reduce the risk of amoxicillin crystalluria, which can lead to renal failure 1
• Monitor urine output closely, as crystalluria can progress to oliguric renal failure in rare cases 1, 2
• Renal impairment from amoxicillin is typically reversible with drug cessation 1

Monitoring for Specific Complications

Interstitial Nephritis and Acute Kidney Injury:

• Monitor renal function (creatinine, BUN) as interstitial nephritis resulting in oliguric renal failure has been reported after amoxicillin overdose 1, 2
• A case report documented acute renal failure in a 3-year-old following ingestion of 574 mg/kg of amoxicillin 2
• Consider hemodialysis in severe cases, as amoxicillin can be removed from circulation by this method 1

Hemolytic Uremic Syndrome (Rare):

• Be aware that amoxicillin can rarely cause hemolytic uremic syndrome with hemolysis, thrombocytopenia, and end-organ damage 3
• If suspected, obtain complete blood count, peripheral smear, LDH, haptoglobin, and renal function tests 3
• Consider plasmapheresis and hemodialysis for confirmed drug-induced HUS 3

Allergic Reactions:

• Penicillin allergic reactions occur in 1-10% of exposures, with up to one-tenth being life-threatening 4
• The most serious reactions can occur in patients with no prior allergy history 4
• Immediate reactions include anaphylaxis, urticaria, and angioedema; delayed reactions include rashes occurring days after exposure 5
• Treat anaphylaxis with standard protocols (epinephrine, antihistamines, corticosteroids, airway management) 4

Special Considerations

Renal Impairment

• High blood levels occur more readily in patients with pre-existing renal impairment due to decreased renal clearance 1
• These patients require closer monitoring and may need hemodialysis for severe toxicity 1

Common Pitfalls to Avoid

• Do not assume all penicillin overdoses are benign: while most ingestions under 250 mg/kg are not associated with significant symptoms, adverse effects can occur through allergic hypersensitivity or direct toxicity 1, 2
• Do not overlook delayed reactions: skin rashes and other manifestations can occur days after exposure 5
• Do not miss crystalluria: maintain high index of suspicion and ensure adequate hydration in all overdose cases 1

Outcome and Follow-up

• Most amoxicillin toxicity is reversible with drug discontinuation and supportive care 1
• Renal impairment typically resolves after cessation of the drug 1
• Document the reaction thoroughly for future antibiotic selection, though true confirmed allergies occur in only approximately 2% of suspected cases 5