Amoxicillin and Clavulanate Potassium

Powder for oral suspension—Colloidal silicon dioxide, hypromellose, mannitol, orange flavor, xanthan gum, aspartame¹, and silicon dioxide.

Each 5 mL of reconstituted Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL contains 0.248 mEq potassium.

Amoxicillin is a semisynthetic antibiotic with a broad spectrum of bactericidal activity against many gram-positive and gram-negative microorganisms. Amoxicillin is, however, susceptible to degradation by β-lactamases, and therefore, its spectrum of activity does not include organisms which produce these enzymes. Clavulanic acid is a β-lactam, structurally related to penicillin, which possesses the ability to inactivate a wide range of β-lactamase enzymes commonly found in microorganisms resistant to penicillins and cephalosporins. In particular, it has good activity against the clinically important plasmid-mediated β-lactamases frequently found responsible for transferred drug resistance.

The clavulanic acid component of Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL protects amoxicillin from degradation by β-lactamase enzymes and effectively extends the antibiotic spectrum of amoxicillin to include many bacteria normally resistant to amoxicillin and other β-lactam antibiotics. Thus, Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL possesses the distinctive properties of a broad-spectrum antibiotic and a β-lactamase inhibitor.

Amoxicillin/clavulanic acid has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Aerobic Gram-Positive Microorganisms:
Streptococcus pneumoniae (including isolates with penicillin MICs ≤2 mcg/mL)

Aerobic Gram-Negative Microorganisms:
Haemophilus influenzae (including β-lactamase–producing isolates)
Moraxella catarrhalis (including β-lactamase–producing isolates)

The following in vitro data are available, but their clinical significance is unknown.

At least 90% of the following microorganisms exhibit in vitro minimum inhibitory concentrations (MICs) less than or equal to the susceptible breakpoint for amoxicillin/clavulanic acid. However, the safety and efficacy of amoxicillin/clavulanic acid in treating infections due to these microorganisms have not been established in adequate and well-controlled trials.

Aerobic Gram-Positive Microorganisms:
Staphylococcus aureus (including β-lactamase–producing isolates)

NOTE: Staphylococci which are resistant to methicillin/oxacillin must be considered resistant to amoxicillin/clavulanic acid.

Streptococcus pyogenes

NOTE: S. pyogenes do not produce β-lactamase, and therefore, are susceptible to amoxicillin alone. Adequate and well-controlled clinical trials have established the effectiveness of amoxicillin alone in treating certain clinical infections due to S. pyogenes.

When available, the clinical microbiology laboratory should provide cumulative results of in vitro susceptibility test results for antimicrobial drugs used in local hospitals and practice areas to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting the most effective antimicrobial.

Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized procedure.^1,2 Standardized procedures are based on dilution methods (broth for S. pneumoniae and H. influenzae) or equivalent with standardized inoculum concentration and standardized concentrations of amoxicillin/clavulanate potassium powder.

The recommended dilution pattern utilizes a constant amoxicillin/clavulanate potassium ratio of 2 to 1 in all tubes with varying amounts of amoxicillin. MICs are expressed in terms of the amoxicillin concentration in the presence of clavulanic acid at a constant 2 parts amoxicillin to 1 part clavulanic acid. The MIC values should be interpreted according to criteria provided in Table 3.

Quantitative methods that require measurement of zone diameters also provides reproducible estimates of the susceptibility of bacteria to antimicrobials. One such standardized technique requires the use of a standardized inoculum concentration.^2,3 This procedure uses paper disks impregnated with 30 mcg amoxicillin/clavulanate potassium (20 mcg amoxicillin plus 10 mcg clavulanate potassium) to test susceptibility of microorganisms to amoxicillin/clavulanate potassium. Disk diffusion zone sizes should be interpreted according to criteria provided in Table 3.

NOTE: Susceptibility of S. pneumoniae should be determined using a 1 mcg oxacillin disk. Isolates with oxacillin zone sizes of ≥20 mm are susceptible to amoxicillin/clavulanic acid. An amoxicillin/clavulanic acid MIC should be determined on isolates of S. pneumoniae with oxacillin zone sizes of ≤19 mm.

NOTE: β-lactamase–negative, ampicillin-resistant H. influenzae isolates must be considered resistant to amoxicillin/clavulanic acid.

A report of S ("Susceptible") indicates that the antimicrobial is likely to inhibit growth of the pathogen if the antimicrobial compound in the blood reaches the concentration usually achievable. A report of I ("Intermediate") indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible antimicrobials, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high doses of antimicrobial can be used. This category also provides a buffer zone that prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of R ("Resistant") indicates that the antimicrobial is not likely to inhibit growth of the pathogen if the antimicrobial compound in the blood reaches the concentration usually achievable; other therapy should be selected.

Standardized susceptibility test procedures require the use of quality control microorganisms to determine the performance of the test procedures.^1–3 Standard amoxicillin/clavulanate potassium powder should provide the MIC ranges for the quality control organisms in Table 4. For the disk diffusion technique, the 30 mcg amoxicillin/clavulanate potassium disk should provide the zone diameter ranges for the quality control organisms in Table 4.

While amoxicillin/clavulanate possesses the characteristic low toxicity of the penicillin group of antibiotics, periodic assessment of organ system functions, including renal, hepatic, and hematopoietic function, is advisable if therapy is for longer than the drug is approved for administration.

A high percentage of patients with mononucleosis who receive ampicillin develop an erythematous skin rash. Thus, ampicillin-class antibiotics should not be administered to patients with mononucleosis.

The possibility of superinfections with mycotic or bacterial pathogens should be kept in mind during therapy. If superinfections occur (usually involving Pseudomonas or Candida), the drug should be discontinued and/ or appropriate therapy instituted.

Prescribing Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL 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.

Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL should be taken every 12 hours with a meal or snack to reduce the possibility of gastrointestinal upset. If diarrhea develops and is severe or lasts more than 2 or 3 days, call your doctor.

Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as 2 or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.

Keep suspension refrigerated. Shake well before using. When dosing a child with the suspension (liquid) of Amoxicillin and Clavulanate Potassium 600 mg/42.9 mg per 5 mL, use a dosing spoon or medicine dropper. Be sure to rinse the spoon or dropper after each use. Bottles of Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL may contain more liquid than required. Follow your doctor's instructions about the amount to use and the days of treatment your child requires. Discard any unused medicine.

Patients should be counseled that antibacterial drugs, including Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may: (1) decrease the effectiveness of the immediate treatment, and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL or other antibacterial drugs in the future.

Each 5 mL of the 600 mg/42.9 mg per 5 mL suspension of amoxicillin and clavulanate potassium for oral suspension contains 7 mg phenylalanine.

Probenecid decreases the renal tubular secretion of amoxicillin. Concurrent use with Amoxicillin and Clavulanate Potassium for Oral Suspension, 600 mg/42.9 mg per 5 mL may result in increased and prolonged blood levels of amoxicillin. Coadministration of probenecid cannot be recommended.

Abnormal prolongation of prothrombin time (increased international normalized ratio [INR]) has been reported rarely in patients receiving amoxicillin and oral anticoagulants. Appropriate monitoring should be undertaken when anticoagulants are prescribed concurrently. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation.

The concurrent administration of allopurinol and ampicillin increases substantially the incidence of rashes in patients receiving both drugs as compared to patients receiving ampicillin alone. It is not known whether this potentiation of ampicillin rashes is due to allopurinol or the hyperuricemia present in these patients. There are no data with Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL and allopurinol administered concurrently.

In common with other broad-spectrum antibiotics, amoxicillin/clavulanate may reduce the efficacy of oral contraceptives.

Oral administration of amoxicillin and clavulanate potassium will result in high urine concentrations of amoxicillin. High urine concentrations of ampicillin 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 therefore Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL, it is recommended that glucose tests based on enzymatic glucose oxidase reactions (such as CLINISTIX^® ) be used.

Following administration of ampicillin to pregnant women, a transient decrease in plasma concentration of total conjugated estriol, estriol-glucuronide, conjugated estrone, and estradiol has been noted. This effect may also occur with amoxicillin and therefore Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL.

Long-term studies in animals have not been performed to evaluate carcinogenic potential. The mutagenic potential of amoxicillin and clavulanate potassium was investigated in vitro with an Ames test, a human lymphocyte cytogenetic assay, a yeast test, and a mouse lymphoma forward mutation assay, and in vivo with mouse micronucleus tests and a dominant lethal test. All were negative apart from the in vitro mouse lymphoma assay where weak activity was found at very high, cytotoxic concentrations. Amoxicillin and clavulanate potassium at oral doses of up to 1,200 mg/kg/day (5.7 times the maximum adult human dose based on body surface area) was found to have no effect on fertility and reproductive performance in rats, dosed with a 2:1 ratio formulation of amoxicillin:clavulanate.

Oral ampicillin-class antibiotics are generally poorly absorbed during labor. Studies in guinea pigs have shown that intravenous administration of ampicillin decreased the uterine tone, frequency of contractions, height of contractions, and duration of contractions. However, it is not known whether the use of amoxicillin and clavulanate potassium in humans during labor or delivery has immediate or delayed adverse effects on the fetus, prolongs the duration of labor, or increases the likelihood that forceps delivery or other obstetrical intervention or resuscitation of the newborn will be necessary. In a single study in women with premature rupture of fetal membranes, it was reported that prophylactic treatment with amoxicillin and clavulanate potassium may be associated with an increased risk of necrotizing enterocolitis in neonates.

Ampicillin-class antibiotics are excreted in human milk; therefore, caution should be exercised when amoxicillin and clavulanate potassium is administered to a nursing woman.

Safety and efficacy of amoxicillin and clavulanate potassium for oral suspension, 600 mg/42.9 mg per 5 mL in infants younger than 3 months have not been established. Safety and efficacy of amoxicillin and clavulanate potassium for oral suspension, 600 mg/42.9 mg per 5 mL have been demonstrated for treatment of acute otitis media in infants and children 3 months to 12 years (see DESCRIPTION OF CLINICAL STUDIES).

The safety and effectiveness of amoxicillin and clavulanate potassium for oral suspension, 600 mg/42.9 mg per 5 mL have been established for the treatment of pediatric patients (3 months to 12 years) with acute bacterial sinusitis. This use is supported by evidence from adequate and well-controlled studies of amoxicillin and clavulanate potassium extended-release tablets (1000 mg/62.5 mg) in adults with acute bacterial sinusitis, studies of amoxicillin and clavulanate potassium for oral suspension, 600 mg/42.9 mg per 5 mL in pediatric patients with acute otitis media, and by similar pharmacokinetics of amoxicillin and clavulanate in pediatric patients taking amoxicillin and clavulanate potassium for oral suspension, 600 mg/42.9 mg per 5 mL (see CLINICAL PHARMACOLOGY) and adults taking amoxicillin and clavulanate potassium extended-release tablets (1000 mg/62.5 mg).

Diarrhea, nausea, vomiting, indigestion, gastritis, stomatitis, glossitis, black "hairy" tongue, mucocutaneous candidiasis, enterocolitis, and hemorrhagic/pseudomembranous colitis. Onset of pseudomembranous colitis symptoms may occur during or after antibiotic treatment. (See WARNINGS.)

Skin rashes, pruritus, urticaria, angioedema, serum sickness–like reactions (urticaria or skin rash accompanied by arthritis, arthralgia, myalgia, and frequently fever), erythema multiforme (rarely Stevens-Johnson syndrome), acute generalized exanthematous pustulosis, hypersensitivity vasculitis, and an occasional case of exfoliative dermatitis (including toxic epidermal necrolysis) have been reported. These reactions may be controlled with antihistamines and, if necessary, systemic corticosteroids. Whenever such reactions occur, the drug should be discontinued, unless the opinion of the physician dictates otherwise. Serious and occasional fatal hypersensitivity (anaphylactic) reactions can occur with oral penicillin. (See WARNINGS.)

A moderate rise in AST (SGOT) and/or ALT (SGPT) has been noted in patients treated with ampicillinclass antibiotics, but the significance of these findings is unknown. Hepatic dysfunction, including hepatitis and cholestatic jaundice (see CONTRAINDICATIONS), increases in serum transaminases (AST and/or ALT), serum bilirubin, and/or alkaline phosphatase, has been infrequently 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. On rare occasions, deaths have been reported (less than 1 death reported per estimated 4 million prescriptions worldwide). These have generally been cases associated with serious underlying diseases or concomitant medications.

Interstitial nephritis and hematuria have been reported rarely. Crystalluria has also been reported (see OVERDOSAGE).

Anemia, including hemolytic anemia, thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukopenia, and agranulocytosis have been reported during therapy with penicillins. These reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena. A slight 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.

Agitation, anxiety, behavioral changes, confusion, convulsions, dizziness, insomnia, and reversible hyperactivity have been reported rarely.

Tooth discoloration (brown, yellow, or gray staining) has been rarely reported. Most reports occurred in pediatric patients. Discoloration was reduced or eliminated with brushing or dental cleaning in most cases.

To minimize the potential for gastrointestinal intolerance, Amoxicillin and Clavulanate Potassium for Oral Suspension 600 mg/42.9 mg per 5 mL should be taken at the start of a meal. Absorption of clavulanate potassium may be enhanced when Amoxicillin and Clavulanate Potassium for Oral Suspension, USP 600 mg/42.9 mg per 5 mL is administered at the start of a meal.

Each 5 mL of reconstituted orange-flavored suspension contains 600 mg amoxicillin and 42.9 mg clavulanic acid as the potassium salt, and is available as follows:

The dry powder and reconstituted suspension are off white to pale yellow in color.

Store reconstituted suspension under refrigeration. Discard unused suspension after 10 days. Store dry powder for oral suspension at 20°–25°C (68°–77°F). See USP controlled room temperature. Dispense in original container.