Bactroban - Drug Monograph

Introduction

Bactroban (mupirocin) is a topical antibiotic medication primarily used for the treatment of skin infections caused by susceptible strains of bacteria. Originally derived from Pseudomonas fluorescens, mupirocin represents a unique class of antibiotics with a distinct mechanism of action that differs from other commonly used antibacterial agents.

Mechanism of Action

Mupirocin exerts its antibacterial effect by selectively and reversibly binding to bacterial isoleucyl-tRNA synthetase, an enzyme essential for protein synthesis. This binding inhibits the incorporation of isoleucine into growing peptide chains, thereby halting bacterial protein production. The drug demonstrates bacteriostatic activity at lower concentrations and bactericidal activity at higher concentrations against susceptible organisms.

Indications

• Treatment of impetigo caused by Staphylococcus aureus (including methicillin-resistant strains) and Streptococcus pyogenes
• Eradication of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) in adult patients and healthcare workers
• Secondary infected traumatic skin lesions (up to 10 cm in length or 100 cm² in area)
• Prophylaxis against staphylococcal infections in patients undergoing surgery or dialysis

Dosage and Administration

• Impetigo: Apply to affected area three times daily for 7-10 days
• Cover treated area with gauze dressing if desired

• MRSA decolonization: Apply half of the single-use tube to each nostril twice daily for 5 days
• Squeeze tube to deliver medication, then gently massage nostrils to spread ointment

• Renal impairment: No dosage adjustment required
• Hepatic impairment: No specific recommendations
• Pediatrics: Safety established for children 2 months and older
• Geriatrics: No specific dosage adjustments required

Pharmacokinetics

Contraindications

• Hypersensitivity to mupirocin or any component of the formulation
• Use on large open wounds or extensive burns due to potential for systemic absorption and toxicity

Warnings and Precautions

• Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi
• Avoid contact with eyes; if contact occurs, rinse thoroughly with water
• Not for ophthalmic, intranasal (except nasal formulation), or intravaginal use
• Use with caution in patients with moderate to severe renal impairment when applied to large surface areas
• Discontinue use if irritation, severe itching, or rash develops
• Potential for allergic reactions, including anaphylaxis in sensitive individuals

Drug Interactions

• No clinically significant drug interactions have been reported due to minimal systemic absorption
• Theoretical potential for interaction with other topical medications applied concurrently

Adverse Effects

• Application site reactions: burning, itching, pain, erythema
• Nasal formulations: headache, rhinitis, upper respiratory congestion

• Contact dermatitis
• Dry skin
• Nausea
• Taste perversion (with nasal application)

• Anaphylaxis
• Severe cutaneous reactions
• Clostridium difficile-associated diarrhea

Monitoring Parameters

• Clinical response to therapy (reduction in erythema, drainage, crusting)
• Signs of superinfection (emergence of non-susceptible organisms)
• Local skin reactions at application site
• For nasal decolonization: follow-up cultures to confirm eradication

Patient Education

• Wash hands before and after application
• Use exactly as prescribed; complete full course of therapy
• Do not apply to large open wounds unless directed by healthcare provider
• Avoid covering treated area with occlusive dressings unless instructed
• Report any signs of allergic reaction (rash, itching, swelling) or lack of improvement
• Store at room temperature; avoid excessive heat
• Do not share medication with others
• Keep out of reach of children

References

1. FDA Prescribing Information: Bactroban (mupirocin) ointment 2. Liu C, et al. Clinical Practice Guidelines by the Infectious Diseases Society of America for the Treatment of Methicillin-Resistant Staphylococcus aureus Infections in Adults and Children. Clin Infect Dis. 2011;52(3):e18-e55 3. Koning S, et al. Interventions for impetigo. Cochrane Database Syst Rev. 2012;(1):CD003261 4. Dryden MS. Complicated skin and soft tissue infection. J Antimicrob Chemother. 2010;65 Suppl 3:iii35-iii44 5. Lexicomp Online: Mupirocin monograph. Wolters Kluwer Clinical Drug Information 6. Micromedex Solutions: Mupirocin drug information. IBM Watson Health