Amoxicillin and Clavulanate Potassium (Page 6 of 7)

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Long‑term studies in animals have not been performed to evaluate carcinogenic potential.

Amoxicillin and clavulanate potassium (4:1 ratio formulation of amoxicillin:clavulanate) was non-mutagenic in the Ames bacterial mutation assay, and the yeast gene conversion assay. Amoxicillin and clavulanate potassium was weakly positive in the mouse lymphoma assay, but the trend toward increased mutation frequencies in this assay occurred at doses that were also associated with decreased cell survival. Amoxicillin and clavulanate potassium was negative in the mouse micronucleus test, and in the dominant lethal assay in mice. Potassium clavulanate alone was tested in the Ames bacterial mutation assay and in the mouse micronucleus test, and was negative in each of these assays.

Amoxicillin and clavulanate potassium (2:1 ratio formulation of amoxicillin:clavulanate) at oral doses of up to 1,200 mg/kg/day was found to have no effect on fertility and reproductive performance in rats. Based on body surface area, this dose of amoxicillin is approximately 4 times the maximum recommended adult human oral dose (875 mg every 12 hours). For clavulanate, the dose multiple is approximately 9 times higher than the maximum recommended adult human oral dose (125 mg every 8 hours), also based on body surface area.

14 CLINICAL STUDIES

14.1 Lower Respiratory Tract and Complicated Urinary Tract Infections

Data from 2 pivotal trials in 1,191 patients treated for either lower respiratory tract infections or complicated urinary tract infections compared a regimen of 875 mg/125 mg tablets of amoxicillin and clavulanate potassium every 12 hours to 500 mg/125 mg tablets of amoxicillin and clavulanate potassium dosed every 8 hours (584 and 607 patients, respectively). Comparable efficacy was demonstrated between the every 12 hours and every 8 hours dosing regimens. There was no significant difference in the percentage of adverse events in each group. The most frequently reported adverse event was diarrhea; incidence rates were similar for the 875 mg/125 mg every 12 hours and 500 mg/125 mg every 8 hours dosing regimens (15% and 14%, respectively); however, there was a statistically significant difference (p < 0.05) in rates of severe diarrhea or withdrawals with diarrhea between the regimens: 1% for 875 mg/125 mg every 12 hours regimen versus 2% for the 500 mg/125 mg every 8 hours regimen.

In one of these pivotal trials, patients with either pyelonephritis (n = 361) or a complicated urinary tract infection (i.e., patients with abnormalities of the urinary tract that predispose to relapse of bacteriuria following eradication, n = 268) were randomized (1:1) to receive either 875 mg/125 mg tablets of amoxicillin and clavulanate potassium every 12 hours (n = 308) or 500 mg/125 mg tablets of amoxicillin and clavulanate potassium every 8 hours (n = 321).

The number of bacteriologically evaluable patients was comparable between the two dosing regimens. Amoxicillin and clavulanate potassium produced comparable bacteriological success rates in patients assessed 2 to 4 days immediately following end of therapy. The bacteriologic efficacy rates were comparable at one of the follow-up visits (5 to 9 days post-therapy) and at a late post-therapy visit (in the majority of cases, this was 2 to 4 weeks post-therapy), as seen in Table 7.

Table 7: Bacteriologic efficacy rates for amoxicillin and clavulanate potassium

Time Post Therapy

875 mg/125 mg

every 12 hours

% (n)

500 mg/125 mg

every 8 hours

% (n)

2 to 4 days

81% (58)

80% (54)

5 to 9 days

58% (41)

52% (52)

2 to 4 weeks

52% (101)

55% (104)

As noted before, though there was no significant difference in the percentage of adverse events in each group, there was a statistically significant difference in rates of severe diarrhea or withdrawals with diarrhea between the regimens.

14.2 Acute Bacterial Otitis Media and Diarrhea in Pediatric Patients

One US/Canadian clinical trial was conducted which compared 45/6.4 mg/kg/day (divided every 12 hours) of amoxicillin and clavulanate potassium for 10 days versus 40/10 mg/kg/day (divided every 8 hours) of amoxicillin and clavulanate potassium for 10 days in the treatment of acute otitis media. Only the suspension formulations were used in this trial. A total of 575 pediatric patients (aged 2 months to 12 years) were enrolled, with an even distribution among the 2 treatment groups and a comparable number of patients were evaluable (i.e., ≥ 84%) per treatment group. Otitis media-specific criteria were required for eligibility and a strong correlation was found at the end of therapy and follow-up between these criteria and physician assessment of clinical response. The clinical efficacy rates at the end of therapy visit (defined as 2 to 4 days after the completion of therapy) and at the follow-up visit (defined as 22 to 28 days post-completion of therapy) were comparable for the 2 treatment groups, with the following cure rates obtained for the evaluable patients: At end of therapy, 87% (n = 265) and 82% (n = 260) for 45 mg/kg/day every 12 hours and 40 mg/kg/day every 8 hours, respectively. At follow-up, 67% (n = 249) and 69% (n = 243) for 45 mg/kg/day every 12 hours and 40 mg/kg/day every 8 hours, respectively.

Diarrhea was defined as either: (a) 3 or more watery or 4 or more loose/watery stools in 1 day; OR (b) 2 watery stools per day or 3 loose/watery stools per day for 2 consecutive days. The incidence of diarrhea was significantly lower in patients who received the every 12 hours regimen compared to patients who received the every 8 hours regimen (14% and 34%, respectively). In addition, the number of patients with either severe diarrhea or who were withdrawn with diarrhea was significantly lower in the every 12 hours treatment group (3% and 8% for the every 12 hours/10 day and every 8 hours/10 day, respectively). In the every 12 hours treatment group, 3 patients (1%) were withdrawn with an allergic reaction, while 1 patient in the every 8 hours group was withdrawn for this reason. The number of patients with a candidal infection of the diaper area was 4% and 6% for the every 12 hours and every 8 hours groups, respectively.

15 REFERENCES

  • 1Swanson-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.
  • 2Clinical 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.
  • 3Clinical 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.
  • 4CLSI. Performance Standards for Antimicrobial Susceptibility Testing: 22nd Informational Supplement. CLSI Document M100-S22. CLSI, Wayne, PA, 2012.

16 HOW SUPPLIED/STORAGE AND HANDLING

Tablets

Amoxicillin and clavulanate potassium tablets, USP 500 mg/125 mg are white to off-white oblong film coated tablets with beveled edges, debossed with 500/125 on one side and AMC on the other side.

NDC 70882-112-20, Package of 20 tablets (2 x 10 unit-of-dose blisters)

Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature].

Keep out of the reach of children.

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