Toxic Dose of Augmentin (Amoxicillin/Clavulanic Acid)
Augmentin overdoses below 250 mg/kg of the amoxicillin component are not associated with significant clinical symptoms in pediatric patients, and treatment of overdosage is primarily supportive with symptom management. 1
Clinical Evidence on Overdosage
- A prospective poison-control center study of 51 pediatric patients demonstrated that amoxicillin overdoses less than 250 mg/kg do not produce significant clinical symptoms 1
- The FDA label does not specify a precise toxic threshold in adults, but the same 250 mg/kg benchmark from pediatric data can serve as a reference point for risk assessment 1
Potential Complications of Overdose
Renal complications are the primary concern with Augmentin overdose, not systemic toxicity:
- Interstitial nephritis resulting in oliguric renal failure has been reported in a small number of patients after amoxicillin overdosage 1
- Crystalluria leading to renal failure has been documented in both adult and pediatric patients following amoxicillin overdose 1
- Renal impairment from overdose appears to be reversible with cessation of the drug 1
Management of Overdose
Discontinue Augmentin immediately and provide supportive care with emphasis on maintaining renal function:
- Adequate fluid intake and diuresis should be maintained to reduce the risk of amoxicillin crystalluria 1
- High blood levels occur more readily in patients with pre-existing renal impairment due to decreased renal clearance 1
- Amoxicillin can be removed from circulation by hemodialysis if clinically indicated 1
- Treatment is symptomatic and supportive, as there is no specific antidote 1
Important Clinical Context
- Approximately 60% of an orally administered dose of amoxicillin is excreted unchanged in the urine within 6-8 hours, making renal function the key determinant of drug clearance 1
- The half-life of amoxicillin is 61.3 minutes in patients with normal renal function 1
- Seizures are listed as a potential adverse effect in the FDA label, particularly with high doses or renal dysfunction, though specific overdose-related seizure data is limited 2, 1