Amoxicillin Drug Information
Generic name: AMOXICILLIN AND CLAVULANATE POTASSIUM
Uses of Amoxicillin
Amoxicillin and Clavulanate Potassium is indicated for the treatment of infections in adults and pediatric patients, due to susceptible isolates of the designated bacteria in the conditions listed below: Lower Respiratory Tract Infections - caused by beta‑lactamase–producing isolates of Haemophilus influenzae and Moraxella catarrhalis. Acute Bacterial Otitis Media - caused by beta‑lactamase–producing isolates of H. influenzae and M. catarrhalis. Sinusitis - caused by beta‑lactamase–producing isolates of H. influenzae and M. catarrhalis.
Skin and Skin Structure Infections - caused by beta‑lactamase–producing isolates of Staphylococcus aureus, Escherichia coli, and Klebsiella species. Urinary Tract Infections - caused by beta‑lactamase–producing isolates of E. coli, Klebsiella species, and Enterobacter species. Amoxicillin and Clavulanate Potassium is a combination of amoxicillin, a penicillin-class antibacterial and clavulanate potassium, a beta‑lactamase inhibitor indicated for treatment of the following infections in adults and pediatric patients: Lower respiratory tract infections Acute bacterial otitis media Sinusitis Skin and skin structure infections Urinary tract infections Limitations of Use When susceptibility test results show susceptibility to amoxicillin, indicating no beta-lactamase production, Amoxicillin and Clavulanate Potassium should not be used.
Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of Amoxicillin and Clavulanate Potassium and other antibacterial drugs, Amoxicillin and Clavulanate Potassium should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria. Limitations of Use When susceptibility test results show susceptibility to amoxicillin, indicating no beta-lactamase production, Amoxicillin and Clavulanate Potassium should not be used. Usage To reduce the development of drug‑resistant bacteria and maintain the effectiveness of Amoxicillin and Clavulanate Potassium and other antibacterial drugs, Amoxicillin and Clavulanate Potassium should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.
When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Dosage & Administration of Amoxicillin
| Severe infections and infections of the respiratory tract | one 875 mg tableta of Amoxicillin and Clavulanate Potassium every 12 hours or one 500 mg tabletb,c of Amoxicillin and Clavulanate Potassium every 8 hours |
|---|---|
| Less severe infections | one 500 mg tabletb,c of Amoxicillin and Clavulanate Potassium every 12 hours or one 250 mg tabletd of Amoxicillin and Clavulanate Potassium every 8 hours |
Side Effects of Amoxicillin
Clinical Trial Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The most frequently reported adverse reactions were diarrhea/loose stools (9%), nausea (3%), skin rashes and urticaria (3%), vomiting (1%) and vaginitis (1%). Less than 3% of patients discontinued therapy because of drug‑related adverse reactions. The overall incidence of adverse reactions, and in particular diarrhea, increased with the higher recommended dose.
Other less frequently reported adverse reactions (less than 1%) include: Abdominal discomfort, flatulence, and headache. In pediatric patients (aged 2 months to 12 years), 1 US/Canadian clinical trial was conducted which compared 45/
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. A total of 575 patients were enrolled, and only the suspension formulations were used in this trial. Overall, the adverse reactions seen were comparable to that noted above; however, there were differences in the rates of diarrhea, skin rashes/urticaria, and diaper area rashes. .
Postmarketing Experience
In addition to adverse reactions reported from clinical trials, the following have been identified during postmarketing use of Amoxicillin and Clavulanate Potassium. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to Amoxicillin and Clavulanate Potassium.
Gastrointestinal: Indigestion, gastritis, stomatitis, glossitis, black “hairy” tongue, mucocutaneous candidiasis, enterocolitis, and hemorrhagic/pseudomembranous colitis. Onset of pseudomembranous colitis symptoms may occur during or after antibacterial treatment. . Immune: Hypersensitivity reactions, anaphylactic/anaphylactoid reactions (including shock), angioedema, serum sickness-like reactions (urticaria or skin rash accompanied by arthritis, arthralgia, myalgia, and frequently fever), hypersensitivity vasculitis . Skin and Appendages: Rashes, pruritus, urticaria, erythema multiforme, SJS, TEN, DRESS, AGEP, exfoliative dermatitis . Liver: Hepatic dysfunction, including hepatitis and cholestatic jaundice, increases in serum transaminases (AST and/or ALT), serum bilirubin, and/or alkaline phosphatase, has been reported with Amoxicillin and Clavulanate Potassium. It has been reported more commonly in the elderly, in males, or in patients on prolonged treatment.
The histologic findings on liver biopsy have consisted of predominantly cholestatic, hepatocellular, or mixed cholestatic hepatocellular changes. The onset of signs/symptoms of hepatic dysfunction may occur during or several weeks after therapy has been discontinued. The hepatic dysfunction, which may be severe, is usually reversible.
Deaths have been reported . Renal: Interstitial nephritis, hematuria, and crystalluria have been reported . Hemic and Lymphatic Systems: Anemia, including hemolytic anemia, thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukopenia, and agranulocytosis have been reported. These reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena. Thrombocytosis was noted in less than 1% of the patients treated with Amoxicillin and Clavulanate Potassium.
There have been reports of increased prothrombin time in patients receiving Amoxicillin and Clavulanate Potassium and anticoagulant therapy concomitantly . Central Nervous System: Agitation, anxiety, behavioral changes, aseptic meningitis, confusion, convulsions, dizziness, insomnia, and reversible hyperactivity have been reported. Miscellaneous: Tooth discoloration (brown, yellow, or gray staining) has been reported. Most reports occurred in pediatric patients.
Discoloration was reduced or eliminated with brushing or dental cleaning in most cases.
Warnings & Cautions for Amoxicillin
Hypersensitivity Reactions Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported
in patients receiving beta-lactam antibacterials, including Amoxicillin and Clavulanate Potassium. These reactions are more likely to occur in individuals with a history of penicillin hypersensitivity and/or a history of sensitivity to multiple allergens. Before initiating therapy with Amoxicillin and Clavulanate Potassium, careful inquiry should be made regarding previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens.
If an allergic reaction occurs, Amoxicillin and Clavulanate Potassium should be discontinued, and appropriate therapy instituted.
Severe Cutaneous Adverse Reactions Amoxicillin and Clavulanate Potassium may cause severe cutaneous
adverse reactions (SCAR), such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP). If patients develop a skin rash, they should be monitored closely, and Amoxicillin and Clavulanate Potassium discontinued if lesions progress.
Hepatic Dysfunction Hepatic dysfunction, including hepatitis and cholestatic jaundice has been associated
with the use of Amoxicillin and Clavulanate Potassium. Hepatic toxicity is usually reversible; however, deaths have been reported. Hepatic function should be monitored at regular intervals in patients with hepatic impairment.
Clostridioides difficile Associated Diarrhea (CDAD) Clostridioides difficile associated diarrhea (CDAD) has been
reported with use of nearly all antibacterial agents, including Amoxicillin and Clavulanate Potassium, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile. C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin-producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy.
CDAD must be considered in all patients who present with diarrhea following antibacterial use. Careful medical history is necessary since CDAD has been reported to occur over 2 months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibacterial use not directed against C. difficile may need to be discontinued.
Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.
Skin Rash in Patients with Mononucleosis
A high percentage of patients with mononucleosis who receive amoxicillin develop an erythematous skin rash. Thus, Amoxicillin and Clavulanate Potassium should not be administered to patients with mononucleosis.
Potential for Microbial Overgrowth
The possibility of superinfections with fungal or bacterial pathogens should be considered during therapy. If superinfection occurs, amoxicillin and clavulanate potassium should be discontinued and appropriate therapy instituted.
Phenylketonurics Amoxicillin and Clavulanate Potassium Chewable tablets and Amoxicillin and Clavulanate Potassium
for Oral Suspension contain aspartame which contains phenylalanine. Each 200 mg chewable tablet of Amoxicillin and Clavulanate Potassium contains
mg phenylalanine; each 400 mg chewable tablet contains 4.2 mg phenylalanine; each
5 mL of either the 200 mg/5 mL or 400 mg/5 mL oral suspension contains 7 mg phenylalanine. The other formulations of Amoxicillin and Clavulanate Potassium do not contain phenylalanine.
Development of Drug-Resistant Bacteria Prescribing Amoxicillin and Clavulanate Potassium in the absence
of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug‑resistant bacteria.
Drug Interactions with Amoxicillin
Probenecid Probenecid decreases the renal tubular secretion of amoxicillin but does not
delay renal excretion of clavulanic acid. Concurrent use with Amoxicillin and Clavulanate Potassium may result in increased and prolonged blood concentrations of amoxicillin. Co-administration of probenecid is not recommended.
Oral Anticoagulants Abnormal prolongation of prothrombin time (increased international normalized ratio )
has been reported in patients receiving amoxicillin and oral anticoagulants. Appropriate monitoring should be undertaken when anticoagulants are prescribed concurrently with Amoxicillin and Clavulanate Potassium. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation.
Allopurinol
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.
Oral Contraceptives Amoxicillin and Clavulanate Potassium 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 Amoxicillin and Clavulanate Potassium, 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.
Pregnancy Safety for Amoxicillin
Pregnancy Teratogenic Effects : Pregnancy Category B. Reproduction studies performed in pregnant rats and mice given Amoxicillin and Clavulanate Potassium (2:1 ratio formulation of amoxicillin:clavulanate) at oral doses up to 1200 mg/kg/day revealed no evidence of harm to the fetus due to Amoxicillin and Clavulanate Potassium. The amoxicillin doses in rats and mice (based on body surface area) were approximately 4 and 2 times the maximum recommended adult human oral dose (875 mg every 12 hours). For clavulanate, these dose multiples were approximately 9 and 4 times the maximum recommended adult human oral dose (125 mg every 8 hours). There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Pediatric Use of Amoxicillin
Pediatric Use The safety and effectiveness of Amoxicillin and Clavulanate Potassium for Oral Suspension and Chewable Tablets have been established in pediatric patients. Use of Amoxicillin and Clavulanate Potassium in pediatric patients is supported by evidence from studies of Amoxicillin and Clavulanate Potassium Tablets in adults with additional data from a study of Amoxicillin and Clavulanate Potassium for Oral Suspension in pediatric patients aged 2 months to 12 years with acute otitis media . Because of incompletely developed renal function in neonates and young infants, the elimination of amoxicillin may be delayed; clavulanate elimination is unaltered in this age group. Dosing of Amoxicillin and Clavulanate Potassium should be modified in pediatric patients aged less than 12 weeks (less than 3 months).
Contraindications for Amoxicillin
Serious Hypersensitivity Reactions Amoxicillin and Clavulanate Potassium 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 Amoxicillin and Clavulanate Potassium is contraindicated in patients with
a previous history of cholestatic jaundice/hepatic dysfunction associated with Amoxicillin and Clavulanate Potassium.
Overdosage Information for Amoxicillin
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 symptoms 1. Interstitial nephritis resulting in oliguric renal failure has been reported in patients after overdosage with amoxicillin and clavulanate potassium. Crystalluria, in some cases leading to renal failure, has also been reported after amoxicillin and 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 and 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 and clavulanate potassium.
Amoxicillin and clavulanate potassium may be removed from circulation by hemodialysis .
Clinical Studies of Amoxicillin
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 less than 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 equals 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 equals 268) were randomized (1:1) to receive either 875 mg/125mg tablets of Amoxicillin and Clavulanate Potassium every 12 hours (n equals 308) or 500 mg/125 mg tablets of Amoxicillin and Clavulanate Potassium every 8 hours (n equals 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 8. Table 8: Bacteriologic efficacy rates for Amoxicillin and Clavulanate Potassium Time Post Therapy 875 mg every 12 hours % (n) 500 mg every 8 hours % (n) 2 to 4 days 81% 80% 5 to 9 days 58% 52% 2 to 4 weeks 52% 55% 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.
Acute Bacterial Otitis Media and Diarrhea in Pediatric Patients One US/Canadian clinical
trial was conducted which compared 45/
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., greater than or equal to 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 equals 265) and 82% (n equals 260) for 45 mg/kg/day every 12 hours and 40 mg/kg/day every 8 hours, respectively. At follow‑up, 67% (n equals 249) and 69% (n equals 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.
It is not known if the finding of a statistically significant reduction in diarrhea with the oral suspensions dosed every 12 hours, versus suspensions dosed every 8 hours of Amoxicillin and Clavulanate Potassium, can be extrapolated to the chewable tablets. The presence of mannitol in the chewable tablets of Amoxicillin and Clavulanate Potassium may contribute to a different diarrhea profile. The every 12 hour oral suspensions (200 mg/
mg per 5 mL and 400 mg/57 mg per 5 mL) are
sweetened with aspartame.
Drug information sourced from the FDA. This content is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before making any medication decisions.
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