Probenecid decreases the renal tubular secretion of amoxicillin but does not delay renal excretion of clavulanic acid. Concurrent use with AUGMENTIN may result in increased and prolonged blood concentrations of amoxicillin. Coadministration of probenecid is not recommended.
Abnormal prolongation of prothrombin time (increased international normalized ratio [INR]) has been reported in patients receiving amoxicillin and oral anticoagulants. Appropriate monitoring should be undertaken when anticoagulants are prescribed concurrently with AUGMENTIN. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation.
The concurrent administration of allopurinol and amoxicillin increases the incidence of rashes in patients receiving both drugs as compared to patients receiving amoxicillin alone. It is not known whether this potentiation of amoxicillin rashes is due to allopurinol or the hyperuricemia present in these patients.
AUGMENTIN may affect intestinal flora, leading to lower estrogen reabsorption and reduced efficacy of combined oral estrogen/progesterone contraceptives.
Effects on Laboratory Tests
High urine concentrations of amoxicillin may result in false-positive reactions when testing for the presence of glucose in urine using CLINITEST®, Benedict’s Solution, or Fehling’s Solution. Since this effect may also occur with AUGMENTIN, it is recommended that glucose tests based on enzymatic glucose oxidase reactions be used.
Following administration of amoxicillin to pregnant women, a transient decrease in plasma concentration of total conjugated estriol, estriol-glucuronide, conjugated estrone, and estradiol has been noted.
In case of overdosage, discontinue medication, treat symptomatically, and institute supportive measures as required. A prospective study of 51 pediatric patients at a poison-control center suggested that overdosages of less than 250 mg/kg of amoxicillin are not associated with significant clinical symptoms1.
Interstitial nephritis resulting in oliguric renal failure has been reported in patients after overdosage with amoxicillin/clavulanate potassium.
Crystalluria, in some cases leading to renal failure, has also been reported after amoxicillin/clavulanate potassium overdosage in adult and pediatric patients. In case of overdosage, adequate fluid intake and diuresis should be maintained to reduce the risk of amoxicillin/clavulanate potassium crystalluria.
Renal impairment appears to be reversible with cessation of drug administration. High blood levels may occur more readily in patients with impaired renal function because of decreased renal clearance of amoxicillin/clavulanate potassium. Amoxicillin/clavulanate potassium may be removed from circulation by hemodialysis. [see Dosage and Administration]
Serious Hypersensitivity Reactions
AUGMENTIN is contraindicated in patients with a history of serious hypersensitivity reactions (e.g., anaphylaxis or Stevens-Johnson syndrome) to amoxicillin, clavulanate or to other beta‑lactam antibacterial drugs (e.g., penicillins and cephalosporins).
Cholestatic Jaundice/Hepatic Dysfunction
AUGMENTIN is contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with AUGMENTIN.
1. Swanson-Biearman B, Dean BS, Lopez G, Krenzelok EP. The effects of penicillin and cephalosporin ingestions in children less than six years of age.Vet Hum Toxicol. 1988; 30: 66‑67.
2. Clinical and Laboratory Standards Institute (CLSI). Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically; Approved Standard – 8th ed. CLSI Document M7-A9. CLSI, 940 West Valley Road, Suite 1400, Wayne, PA, 19087, 2012.
3. Clinical and Laboratory Standards Institute (CLSI). Performance Standard for Antimicrobial Disk Susceptibility Tests;Approved Standard – 11th ed. CLSI Document M2-A11. CLSI, 940 West Valley Road, Suite 1400, Wayne, PA, 19087, 2012.
4. CLSI. Performance Standards for Antimicrobial Susceptibility Testing: 22nd Informational Supplement. CLSI document M100-S22. CLSI, Wayne, PA, 2012.