BACTROBAN CREAM

DESCRIPTION

BACTROBAN (mupirocin calcium) cream, 2% contains the dihydrate crystalline calcium hemi-salt of the RNA synthetase inhibitor antibacterial, mupirocin. Chemically, it is (αE,2S,3R,4R,5S)-5-[(2S,3S,4S,5S)-2,3-epoxy-5-hydroxy-4-methylhexyl]tetrahydro-3,4-dihydroxy-β-methyl-2H-pyran-2-crotonic acid, ester with 9-hydroxynonanoic acid, calcium salt (2:1), dihydrate.

The molecular formula of mupirocin calcium is (C₂₆H₄₃O₉)₂Ca•2H₂O, and the molecular weight is 1075.3. The molecular weight of mupirocin free acid is 500.6. The structural formula of mupirocin calcium is:

Figure 1: Structure of Mupirocin Calcium

BACTROBAN cream is a white cream that contains 2.15% w/w mupirocin calcium (equivalent to 2% mupirocin free acid) in an oil- and water-based emulsion. The inactive ingredients are benzyl alcohol, cetomacrogol 1000, cetyl alcohol, mineral oil, phenoxyethanol, purified water, stearyl alcohol, and xanthan gum.

INDICATIONS

BACTROBAN® cream is indicated for the treatment of secondarily infected traumatic skin lesions (up to 10 cm in length or 100 cm² in area) due to susceptible isolates of Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes).

DOSAGE AND ADMINISTRATION

• For Topical Use Only.
• Apply a small amount of BACTROBAN cream, with a cotton swab or gauze pad, to the affected area 3 times daily for 10 days.
• Cover the treated area with gauze dressing if desired.
• Re-evaluate patients not showing a clinical response within 3 to 5 days.
• It is not for intranasal, ophthalmic, or other mucosal use [see WARNINGS AND PRECAUTIONS].
• Do not apply this concurrently with any other lotions, creams or ointments [see CLINICAL PHARMACOLOGY].

HOW SUPPLIED

Dosage Forms And Strengths

BACTROBAN cream is a white cream that contains 2.15% w/w mupirocin calcium (equivalent to 2% mupirocin free acid) in an oil- and water-based emulsion supplied in 15-gram and 30-gram tubes.

Storage And Handling

2% is supplied in 15-gram and 30-gram tubes.

BACTROBAN cream is a white cream that contains 2.15% w/w mupirocin calcium (equivalent to 2% mupirocin free acid) in an oil- and water-based emulsion.

NDC 0029-1527-22 (15-gram tube)
NDC 0029-1527-25 (30-gram tube)

Store at or below 25°C (77°F). Do not freeze.

GlaxoSmithKline, Research Triangle Park, NC 27709. Revised: December 2015

SIDE EFFECTS

The following adverse reactions are discussed in more detail in other sections of the labeling:

• Severe Allergic Reactions [see WARNINGS AND PRECAUTIONS]
• Eye Irritation [see WARNINGS AND PRECAUTIONS]
• Local Irritation [see WARNINGS AND PRECAUTIONS]
• Clostridium difficile-Associated Diarrhea [see WARNINGS AND PRECAUTIONS]

Clinical Trials 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 with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In 2 randomized, double-blind, double-dummy trials, 339 subjects were treated with topical BACTROBAN cream plus oral placebo. Adverse reactions occurred in 28 (8.3%) subjects. The following adverse reactions were reported by at least 1% of subjects in connection with the use in clinical trials: headache (1.7%), rash (1.1%), and nausea (1.1%).

Other adverse reactions which occurred in less than 1% of subjects were: abdominal pain, burning at application site, cellulitis, dermatitis, dizziness, pruritus, secondary wound infection, and ulcerative stomatitis.

In a supportive trial in the treatment of secondarily infected eczema, 82 subjects were treated with BACTROBAN cream. The incidence of adverse reactions was as follows: nausea (4.9%), headache and burning at application site (3.6% each), pruritus (2.4%), and 1 report each of abdominal pain, bleeding secondary to eczema, pain secondary to eczema, hives, dry skin, and rash.

Postmarketing Experience

In addition to adverse reactions reported from clinical trials, the following reactions have been identified during postmarketing use of BACTROBAN cream. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These reactions have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal relationship to BACTROBAN cream.

Immune System Disorders

Systemic allergic reactions, including anaphylaxis, urticaria, angioedema, and generalized rash [see WARNINGS AND PRECAUTIONS].

DRUG INTERACTIONS

No information provided.

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Severe Allergic Reactions

Systemic allergic reactions, including anaphylaxis, urticaria, angioedema, and generalized rash, have been reported in patients treated with formulations of BACTROBAN, including BACTROBAN cream [see ADVERSE REACTIONS].

Eye Irritation

Avoid contact with the eyes. In case of accidental contact, rinse well with water.

Local Irritation

In the event of a sensitization or severe local irritation, usage should be discontinued, and appropriate alternative therapy for the infection instituted.

Clostridium Difficile-Associated Diarrhea

Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents 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 drug 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 drug 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.

Potential For Microbial Overgrowth

As with other antibacterial products, prolonged use may result in overgrowth of nonsusceptible microorganisms, including fungi [see DOSAGE AND ADMINISTRATION].

Risk Associated With Mucosal Use

BACTROBAN cream is not formulated for use on mucosal surfaces. A separate formulation, BACTROBAN® (mupirocin calcium) nasal ointment, is available for intranasal use.

Patient Counseling Information

Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION).

Advise the patient to administer BACTROBAN cream as follows:

• Use BACTROBAN cream only as directed by the healthcare provider. It is for external use only. Avoid contact of BACTROBAN cream with the eyes. If BACTROBAN cream gets in the eyes, rinse thoroughly with water.
• Do not use this in the nose.
• Wash your hands before and after applying.
• Use a gauze pad or cotton swab to apply a small amount of BACTROBAN cream to the affected area. The treated area may be covered by gauze dressing if desired.
• Report to the healthcare provider any signs of local adverse reactions. BACTROBAN cream should be stopped and the healthcare provider contacted if irritation, severe itching, or rash occurs.
• Report to the healthcare provider or go to the nearest emergency room if severe allergic reactions, such as swelling of the lips, face, or tongue, or wheezing occur [see WARNINGS AND PRECAUTIONS].
• If no improvement is seen in 3 to 5 days, contact the healthcare provider.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Long-term studies in animals to evaluate carcinogenic potential of mupirocin calcium have not been conducted.

Results of the following studies performed with mupirocin calcium or mupirocin sodium in vitro and in vivo did not indicate a potential for genotoxicity: rat primary hepatocyte unscheduled DNA synthesis, sediment analysis for DNA strand breaks, Salmonella reversion test (Ames), Escherichia coli mutation assay, metaphase analysis of human lymphocytes, mouse lymphoma assay, and bone marrow micronuclei assay in mice.

Reproduction studies were performed with mupirocin administered subcutaneously to male and female rats at doses up to 100 mg per kg per day which is 14 times the human topical dose (approximately 60 mg mupirocin per day) based on body surface area. Neither evidence of impaired fertility nor impaired reproductive performance attributable to mupirocin was observed.

Use In Specific Populations

Pregnancy

Pregnancy Category B

There are no adequate and well-controlled studies of BACTROBAN cream (contains equivalent of 2% mupirocin free acid) 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.

Developmental toxicity studies have been performed with mupirocin administered subcutaneously to rats and rabbits at doses up to 160 mg per kg per day in both species. This dose is 22 and 43 times, respectively, the human topical dose (approximately 60 mg mupirocin per day) based on body surface area. There was no evidence of fetal harm due to mupirocin.

Nursing Mothers

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when it is administered to a nursing woman.

Pediatric Use

The safety and effectiveness of BACTROBAN cream have been established in the age-groups 3 months to 16 years. Use of BACTROBAN cream in these age-groups is supported by evidence from adequate and well-controlled trials in adults with additional data from 93 pediatric subjects studied as part of the pivotal trials in adults [see Clinical Studies].

Geriatric Use

In 2 adequate and well-controlled trials, 30 subjects older than 65 years were treated with BACTROBAN cream. No overall difference in the efficacy or safety was observed in this patient population when compared with that observed in younger patients.

OVERDOSE

No information provided.

CONTRAINDICATIONS

BACTROBAN cream is contraindicated in patients with known hypersensitivity to mupirocin or any of the excipients.

CLINICAL PHARMACOLOGY

Mechanism Of Action

Mupirocin is an RNA synthetase inhibitor antibacterial [see Microbiology].

Pharmacokinetics

Absorption

Systemic absorption of mupirocin through intact human skin is minimal. The systemic absorption of mupirocin was studied following application of BACTROBAN cream 3 times daily for 5 days to various skin lesions greater than 10 cm in length or 100 cm² in area in 16 adults (aged 29 to 60 years) and 10 children (aged 3 to 12 years). Some systemic absorption was observed as evidenced by the detection of the metabolite, monic acid, in urine. Data from this trial indicated more frequent occurrence of percutaneous absorption in children (90% of subjects) compared with adults (44% of subjects); however, the observed urinary concentrations in children (0.07 to 1.3 mcg per mL [1 pediatric subject had no detectable level]) are within the observed range (0.08 to 10.03 mcg per mL [9 adults had no detectable level]) in the adult population. In general, the degree of percutaneous absorption following multiple dosing appears to be minimal in adults and children.

The effect of the concurrent application of this with other topical products has not been studied [see DOSAGE AND ADMINISTRATION].

Elimination

In a trial conducted in 7 healthy adult male subjects, the elimination half-life after intravenous administration of mupirocin was 20 to 40 minutes for mupirocin and 30 to 80 minutes for monic acid.

Metabolism: Following intravenous or oral administration, mupirocin is rapidly metabolized. The principal metabolite, monic acid, demonstrates no antibacterial activity.

Excretion: Monic acid is predominantly eliminated by renal excretion.

Special Populations

Renal Impairment: The pharmacokinetics of mupirocin have not been studied in individuals with renal insufficiency.

Microbiology

Mupirocin is an RNA synthetase inhibitor antibacterial produced by fermentation using the organism Pseudomonas fluorescens.

Mechanism of Action

Mupirocin inhibits bacterial protein synthesis by reversibly and specifically binding to bacterial isoleucyl-transfer RNA (tRNA) synthetase.

Mupirocin is bactericidal at concentrations achieved by topical administration. Mupirocin is highly protein bound (greater than 97%) and the effect of wound secretions on the minimum inhibitory concentrations (MICs) of mupirocin has not been determined.

Mechanism of Resistance

When mupirocin resistance occurs, it results from the production of a modified isoleucyl-tRNA synthetase, or the acquisition of, by genetic transfer, a plasmid mediating a new isoleucyl-tRNA synthetase. High-level plasmid-mediated resistance (MIC ≥ 512 mcg/mL) has been reported in increasing numbers of isolates of S. aureus and with higher frequency in coagulase-negative staphylococci. Mupirocin resistance occurs with greater frequency in methicillin-resistant than methicillin-susceptible staphylococci.

Cross Resistance

Due to its mode of action, mupirocin does not demonstrate cross resistance with other classes of antimicrobial agents.

Antimicrobial Activity

Mupirocin has been shown to be active against susceptible isolates of S. aureus and S. pyogenes, both in vitro and in clinical trials [see INDICATIONS AND USAGE]. The following in vitro data are available, but their clinical significance is unknown. Mupirocin is active against most isolates of Staphylococcus epidermidis.

Susceptibility Testing

High-level mupirocin resistance ( ≥ 512 mcg/mL) may be determined using standard disk diffusion or broth microdilution tests.^1,2 Because of the occurrence of mupirocin resistance in methicillin-resistant S. aureus (MRSA), it is appropriate to test MRSA populations for mupirocin susceptibility prior to the use of mupirocin using a standardized method.^3,4,5

Clinical Studies

The efficacy of topical BACTROBAN cream for the treatment of secondarily infected traumatic skin lesions (e.g., lacerations, sutured wounds, and abrasions not more than 10 cm in length or 100 cm² in total area) was compared with that of oral cephalexin in 2 randomized, double-blind, double-dummy clinical trials. Clinical efficacy rates at follow-up in the per-protocol populations (adults and pediatric subjects included) were 96.1% for BACTROBAN cream (n = 231) and 93.1% for oral cephalexin (n = 219). Pathogen eradication rates at follow-up in the per-protocol populations were 100% for both BACTROBAN cream and oral cephalexin.

Pediatrics

There were 93 pediatric subjects aged 2 weeks to 16 years enrolled per protocol in the secondarily infected skin lesion trials, although only 3 were younger than 2 years of age in the population treated with BACTROBAN cream. Subjects were randomized to either 10 days of topical BACTROBAN cream 3 times daily or 10 days of oral cephalexin (250 mg 4 times daily for subjects greater than 40 kg or 25 mg per kg per day oral suspension in 4 divided doses for subjects less than or equal to 40 kg). Clinical efficacy at follow-up (7 to 12 days post-therapy) in the per-protocol populations was 97.7% (43 of 44) for BACTROBAN cream and 93.9% (46 of 49) for cephalexin.

REFERENCES

1. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing; Twenty-fifth Informational Supplement. CLSI document M100-S25. Clinical and Laboratory Standards Institute, 950 West Valley Rd., Suite 2500, Wayne, PA 19087, USA, 2015.

2. Patel J, Gorwitz RJ, et al. Mupirocin Resistance. Clinical Infectious Diseases. 2009; 49(6): 935-41.

3. Clinical and Laboratory Standards Institute (CLSI). Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically; Approved Standard – Tenth Edition. CLSI document M07-A10. Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087, USA, 2015.

4. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Disk Diffusion Susceptibility Tests; Approved Standard – Twelfth Edition. CLSI document M02-A12. Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087, USA, 2015.

5. Finlay JE, Miller LA, Poupard JA. Interpretive criteria for testing susceptibility of staphylococci to mupirocin. Antimicrob Agents Chemother 1997;41(5):1137-1139.