Symptoms: Following overdosage, patients have experienced primarily GI symptoms including stomach and abdominal pain, vomiting, and diarrhea. Disturbance of the fluid and electrolyte balances may be evident. Rash, hyperactivity or drowsiness has also been observed in a small number of patients.
Interstitial nephritis resulting in oliguric renal failure has been reported in a small number of patients after overdosage with amoxicillin.
Crystalluria, in some cases leading to renal failure, has also been reported after amoxicillin overdosage in adult and pediatric patients.
Treatment: In the case of overdosage, discontinue amoxicillin/clavulanate potassium, treat symptomatically and institute supportive measures as required. If the overdosage is very recent and there is no contraindication, an attempt at emesis or other means of removal of drug from the stomach may be performed. A prospective study of 51 pediatric patients at a poison center suggested that overdosages of <250 mg/kg of amoxicillin are not associated with significant clinical symptoms and do not require gastric emptying. Co-amoxiclav can be removed from the circulation by hemodialysis.
Adequate fluid intake and diuresis should be maintained to reduce the risk of amoxicillin crystalluria.
Renal impairment appears to be reversible with cessation of co-amoxiclav administration. High blood levels may occur more readily in patients with impaired renal function because of decreased renal clearance of both amoxicillin and clavulanate. Both amoxicillin and clavulanate are removed from the circulation by hemodialysis (see Dosage & Administration for recommended dosing for patients with impaired renal function).