Mupirocin
Bactroban, Centany (mupirocin calcium)
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Impetigo (due to susceptible S. aureus and S. pyogenes) | ≥2 months (ointment) | Monotherapy (topical) | FDA Approved |
| Secondarily infected traumatic skin lesions (lacerations, sutured wounds, abrasions ≤10 cm or 100 cm²; due to S. aureus and S. pyogenes) | ≥3 months (cream) | Monotherapy (topical) | FDA Approved |
| Nasal MRSA decolonization (eradication of nasal colonisation with methicillin-resistant S. aureus during institutional outbreaks) | ≥12 years & healthcare workers | Part of comprehensive infection control programme | FDA Approved |
Mupirocin occupies a distinctive niche in dermatology and infection control as a topical-only antibacterial with excellent activity against staphylococci and streptococci. Its unique mechanism means cross-resistance with systemic antibiotics does not occur, though high-level mupirocin resistance (MIC ≥512 mcg/mL) is reported with increasing frequency, especially in MRSA isolates. Susceptibility testing is recommended before using the nasal formulation for MRSA decolonisation.
Minor skin infections (folliculitis, furunculosis): Topical mupirocin is widely used for localised superficial staphylococcal skin infections beyond impetigo. Evidence quality: Moderate
Perioperative S. aureus decolonisation: Intranasal mupirocin (with or without chlorhexidine body washes) before cardiothoracic, orthopaedic, or other high-risk surgery to reduce surgical site infections. Supported by the SHEA/IDSA 2022 guidelines and WHO SSI prevention guidelines. Evidence quality: High
Recurrent community-onset SSTI decolonisation: Five-day intranasal mupirocin combined with chlorhexidine washes and environmental decontamination for patients with recurrent staphylococcal skin and soft tissue infections (IDSA 2014 SSTI guideline). Evidence quality: Moderate
Universal ICU decolonisation: Twice-daily intranasal mupirocin for five days plus daily chlorhexidine bathing in adult ICU patients to reduce MRSA infections and all-cause bloodstream infections (REDUCE MRSA Trial). Evidence quality: High
Dosing
Adult & Pediatric Dosing by Clinical Scenario
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Impetigo — localised, non-bullous (ointment 2%) | Apply TID | Small amount to affected area TID × 10 days | 10 days total treatment | Apply with cotton swab or gauze. May cover with gauze dressing. Re-evaluate if no response at 3–5 days. Ages ≥2 months (FDA PI) |
| Secondarily infected wounds — lacerations, abrasions (cream 2%) | Apply TID | Small amount to affected area TID × 10 days | 10 days total treatment | Lesion must be ≤10 cm in length or 100 cm². Do not co-apply other topical products on same site. Ages ≥3 months (FDA PI) |
| MRSA nasal decolonisation — institutional outbreak (nasal ointment 2%) | ½ tube per nostril BID | ~0.5 g per nostril BID × 5 days | 5 days total | Press nostrils together and massage to distribute. Single-use tube, discard after each application. Ages ≥12 years and healthcare workers (FDA PI) |
| Perioperative S. aureus decolonisation (off-label, nasal ointment 2%) | ½ tube per nostril BID | BID × 5 days preoperatively | 5 days | Combine with chlorhexidine body washes per institutional protocol. Start 5 days before scheduled surgery. SHEA/IDSA 2022; WHO SSI guideline |
| Recurrent SSTI decolonisation (off-label, nasal ointment 2%) | ½ tube per nostril BID | BID × 5–10 days | 10 days | Combine with chlorhexidine washes × 5–14 days and environmental decontamination. Consider household contacts. IDSA MRSA guideline 2011 |
| Universal ICU decolonisation (off-label, nasal ointment 2%) | ½ tube per nostril BID | BID × 5 days | 5 days | Pair with daily chlorhexidine bathing for all ICU patients. Institutional infection control oversight required. REDUCE MRSA Trial protocol |
The three mupirocin formulations are not interchangeable. The ointment (polyethylene glycol base) is for impetigo only and must not be used intranasally or on mucosal surfaces. The cream (oil-in-water emulsion) is for secondarily infected traumatic wounds. The nasal ointment (paraffin base) is specifically designed for intranasal application. Using the PEG-based ointment intranasally has been associated with stinging and drying and is not recommended.
Special Populations
| Population | Recommendation | Key Consideration |
|---|---|---|
| Renal impairment | Avoid the PEG-based ointment on large open wounds if moderate-to-severe renal impairment | Polyethylene glycol can be absorbed through damaged skin and is renally excreted; risk of PEG nephrotoxicity |
| Paediatric (<2 months) | Safety and efficacy not established for ointment | Significant systemic absorption of nasal formulation in neonates and premature infants; avoid nasal ointment under 12 years |
| Elderly | No dose adjustment required | No differences in safety or efficacy observed in patients >65 years in clinical trials |
| Pregnancy | Use only if clearly needed | No developmental toxicity at doses up to 22× (rats) and 11× (rabbits) human topical dose; minimal systemic absorption |
Pharmacology
Mechanism of Action
Mupirocin is a naturally occurring antibacterial derived from Pseudomonas fluorescens fermentation. It exerts its antimicrobial effect by reversibly and specifically binding to bacterial isoleucyl transfer-RNA (tRNA) synthetase, an enzyme essential for incorporating isoleucine into nascent bacterial proteins. This interaction blocks protein synthesis at the aminoacyl-tRNA charging step, a target not shared by any other antibiotic class. At concentrations achievable by topical application, mupirocin is bactericidal against susceptible organisms, particularly Staphylococcus aureus (including many MRSA strains) and Streptococcus pyogenes. Resistance arises either through point mutations in the native isoleucyl-tRNA synthetase (low-level, MIC 8–256 mcg/mL) or by acquisition of a plasmid-encoded alternative synthetase gene (mupA/ileS2), which confers high-level resistance (MIC ≥512 mcg/mL).
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Topical (intact skin): undetectable (<1.1 ng/mL blood after 24 h occlusion); Topical (damaged skin): ≤1.25% of dose absorbed; Intranasal: ~3.3% (range 1.2–5.1%) | Negligible systemic exposure with dermal application; intranasal absorption slightly higher but still low, making systemic toxicity extremely unlikely |
| Distribution | Protein binding >97%; concentrates in stratum corneum (detectable 72 h post-application) | High local tissue concentration at the site of infection; high protein binding means systemic drug interactions are not clinically relevant |
| Metabolism | Rapid hydrolysis to monic acid (inactive metabolite) after any systemic absorption | Monic acid has no antibacterial activity, so any absorbed drug is rapidly inactivated; does not involve CYP enzymes |
| Elimination | Monic acid: renal excretion; IV t½ 20–40 min (parent), 30–80 min (monic acid) | Very short half-life means no systemic accumulation with topical dosing; caution with PEG-based ointment in renal impairment due to excipient absorption |
Side Effects
Mupirocin is generally well tolerated across all formulations. Most adverse effects are mild, local, and self-limiting. Incidence data below are drawn from pivotal clinical trials reported in the FDA-approved prescribing information for each formulation.
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Burning, stinging, or pain at application site | 1.5% (ointment) | Typically transient, resolves within minutes; more common with polyethylene glycol ointment base |
| Headache | 1.7% (cream) | Reported in pivotal cream trials; mechanism unclear given minimal systemic absorption |
| Rash | 1.1% (cream) | Distinguish from worsening infection; discontinue if extensive |
| Nausea | 1.1% (cream) | Reported in cream trials; rarely treatment-limiting |
| Itching / pruritus | 1.0% (ointment) | May overlap with underlying skin condition; assess for contact sensitisation if persistent |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Headache | 9% | Most common reported event; typically mild and self-limiting over the 5-day course |
| Rhinitis | 6% | Expected with intranasal application; rarely requires discontinuation |
| Respiratory disorder / upper respiratory congestion | 5% | Nasal stuffiness common during treatment; resolves after completion |
| Pharyngitis | 4% | Possible post-nasal drip effect |
| Taste perversion | 3% | Altered or metallic taste; resolves after treatment completion |
| Burning / stinging (nasal) | 2% | Brief stinging on application; generally well tolerated |
| Cough | 2% | Mild; may relate to post-nasal drip or nasal irritation |
| Pruritus (nasal) | 1% | Local irritation; reassure patients it is expected |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Anaphylaxis | Very rare | Minutes to hours after application | Immediate discontinuation; emergency treatment with epinephrine; permanent discontinuation of all mupirocin formulations |
| Angioedema | Very rare | Minutes to hours | Discontinue immediately; assess airway; antihistamines and/or epinephrine as indicated |
| Generalised urticaria | Very rare | Hours to days | Discontinue; oral antihistamines; monitor for progression to anaphylaxis |
| Clostridioides difficile–associated diarrhoea (CDAD) | Very rare | During or up to 2 months after treatment | Discontinue mupirocin if CDAD suspected; obtain stool testing; initiate targeted therapy if confirmed |
| Severe local sensitisation / contact dermatitis | Rare | Days into treatment | Discontinue mupirocin; switch to alternative topical antibacterial; consider patch testing if rechallenge planned |
| Severe ocular irritation (if accidentally applied to eyes) | Rare (accidental exposure) | Immediate | Copious water irrigation; ophthalmology referral if symptoms persist beyond 48 hours |
| Reason for Discontinuation | Incidence | Context |
|---|---|---|
| Local irritation / sensitisation | <1% | Primary reason across all formulations; includes burning, rash, and contact dermatitis |
| Allergic reaction | Very rare | Anaphylaxis, angioedema, or generalised urticaria mandating permanent discontinuation |
Burning or stinging on application is the most frequently encountered complaint. It typically lasts 1–3 minutes and resolves spontaneously. If irritation worsens or a rash develops, this may indicate contact sensitisation to the drug or excipients (particularly polyethylene glycol in the ointment base). Switching from the ointment to the cream formulation (or vice versa) may help, as the excipient profiles differ substantially. Persistent or worsening symptoms warrant reassessment of the diagnosis and consideration of alternative agents such as retapamulin or ozenoxacin.
Drug Interactions
Mupirocin has a remarkably clean interaction profile owing to its negligible systemic absorption and non-CYP metabolism. The FDA prescribing information states that the effect of concurrent application with other topical products has not been formally studied. There are no known clinically significant systemic drug–drug interactions. The interactions below are primarily formulation- and application-based considerations rather than classical pharmacokinetic interactions.
Monitoring
-
Clinical Response
Day 3–5 of therapy
Routine Reassess infection site for improvement (reduced erythema, crusting, purulence). If no clinical response within 3–5 days, reconsider diagnosis, obtain wound culture, and switch to alternative therapy. Do not continue beyond 10 days. -
Local Skin Reaction
Each application
Routine Watch for worsening redness, swelling, rash, or blistering at the application site, which may indicate contact sensitisation rather than therapeutic effect. Discontinue if severe irritation develops. -
Allergic Reaction Signs
During treatment
Trigger-based Counsel patients to seek immediate medical attention for lip or facial swelling, difficulty breathing, widespread hives, or generalised rash. Although very rare, systemic allergic reactions including anaphylaxis have been reported. -
Superinfection / Fungal Overgrowth
If prolonged use
Trigger-based Prolonged or repeated courses may promote overgrowth of non-susceptible organisms including fungi. Reassess if new lesion morphology appears during treatment. Use the shortest effective course. -
MRSA Susceptibility
Before nasal decolonisation
Routine Test MRSA isolates for mupirocin susceptibility prior to initiating nasal decolonisation. High-level resistance (MIC ≥512 mcg/mL) precludes efficacy. Mupirocin resistance is more common in MRSA than MSSA strains. -
Renal Function
Before use on large wounds
Trigger-based Assess renal function before applying PEG-based ointment to extensive wounds or denuded skin. Avoid in patients with moderate-to-severe renal impairment due to risk of PEG accumulation.
Contraindications & Cautions
Absolute Contraindications
- Known hypersensitivity to mupirocin or any excipient in the formulation (polyethylene glycol for ointment; benzyl alcohol, cetyl alcohol, mineral oil for cream; paraffin, glycerin esters for nasal ointment)
Relative Contraindications (Specialist Input Recommended)
- Large open or deep wounds with moderate-to-severe renal impairment: The polyethylene glycol ointment base can be absorbed through damaged skin and accumulates when renal clearance is impaired. Use the cream formulation instead, or consult nephrology.
- Known high-level mupirocin-resistant MRSA (MIC ≥512 mcg/mL): Nasal decolonisation will be ineffective. Discuss alternative decolonisation strategies with infection control or infectious disease specialists.
- Neonates and premature infants (nasal formulation): Significant systemic absorption has been demonstrated in this population, unlike in adults. Pharmacokinetics are not well characterised; safety has not been established.
Use with Caution
- Near the eyes: Avoid contact; if accidental ocular exposure occurs, rinse thoroughly with water. The nasal formulation can cause severe burning and tearing if applied to the eye.
- Mucosal surfaces (ointment and cream): The topical ointment and cream are not formulated for mucosal use. Only the nasal ointment (paraffin base) should be used intranasally.
- Intravenous catheter sites: Mupirocin ointment must not be applied at IV cannulae or central line insertion sites due to the potential to promote fungal infections and antimicrobial resistance.
- Repeated or prolonged courses: May select for mupirocin-resistant organisms. Reserve repeat courses for documented susceptible infections and avoid chronic use.
- Pregnancy: Use only if clearly needed. No adequate controlled studies in pregnant women, though animal studies at supratherapeutic doses showed no fetal harm.
All antibacterial drug products carry the general FDA advisory that prescribing antibacterial drugs in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit and increases the risk of drug-resistant organisms. For mupirocin specifically, the emergence of high-level resistance (particularly in MRSA populations) has been documented with increasing frequency, and injudicious or prolonged use accelerates this process. MRSA populations should be tested for mupirocin susceptibility before intranasal decolonisation.
Patient Counselling
Purpose of Therapy
Mupirocin is a prescription antibiotic applied directly to the skin or inside the nose to treat or prevent bacterial infections caused by staphylococci and streptococci. When used on the skin, it treats infections such as impetigo (a contagious skin rash with honey-coloured crusts) or infected cuts and scrapes. When used in the nose, it eliminates bacteria that could otherwise cause serious infections, particularly in hospital settings.
How to Apply
Skin (ointment or cream): Wash hands thoroughly before and after application. Apply a small amount to the affected area using a clean cotton swab or gauze pad three times daily. The treated area may be covered with a gauze dressing if desired. Complete the full prescribed course even if the infection appears to improve before finishing. Nasal ointment: Squeeze approximately half of the single-use tube into one nostril and the other half into the other nostril. Gently press the sides of the nose together and massage to spread the ointment throughout. Discard the tube after use; do not reuse.
Sources
- Mupirocin Ointment USP, 2% — Full Prescribing Information. FDA label (revised 2025). accessdata.fda.gov Primary regulatory source for the topical ointment formulation; provides approved indications, dosing, adverse reactions, and pharmacokinetic data for impetigo.
- BACTROBAN (mupirocin calcium) Cream, 2% — Full Prescribing Information. GlaxoSmithKline (revised 2020). accessdata.fda.gov Regulatory source for the cream formulation; covers secondarily infected traumatic skin lesions, paediatric data, and the emulsion base formulation.
- BACTROBAN Nasal (mupirocin calcium) Ointment, 2% — Full Prescribing Information. GlaxoSmithKline (revised 2020). accessdata.fda.gov Regulatory source for the nasal ointment; provides MRSA decolonisation indication, adverse reaction rates from US and foreign trials, and neonatal PK warning.
- Huang SS, Septimus E, Kleinman K, et al. Targeted versus universal decolonization to prevent ICU infection. N Engl J Med. 2013;368(24):2255–2265. doi:10.1056/NEJMoa1207290 The REDUCE MRSA Trial — landmark 43-hospital cluster-randomised trial showing universal decolonisation with mupirocin and chlorhexidine reduced MRSA isolates by 37% and all-cause BSIs by 44% in ICUs.
- Perl TM, Cullen JJ, Wenzel RP, et al. Intranasal mupirocin to prevent postoperative Staphylococcus aureus infections. N Engl J Med. 2002;346(24):1871–1877. doi:10.1056/NEJMoa003069 RCT evaluating perioperative intranasal mupirocin for prevention of surgical site infections; demonstrated reduced nosocomial S. aureus infections among nasal carriers.
- Bode LGM, Kluytmans JAJW, Wertheim HFL, et al. Preventing surgical-site infections in nasal carriers of Staphylococcus aureus. N Engl J Med. 2010;362(1):9–17. doi:10.1056/NEJMoa0808939 Demonstrated that rapid screening and decolonisation with mupirocin and chlorhexidine significantly reduced S. aureus surgical site infections.
- Liu C, Bayer A, Cosgrove SE, et al. Clinical practice guidelines by the IDSA for the treatment of MRSA infections in adults and children. Clin Infect Dis. 2011;52(3):e18–e55. doi:10.1093/cid/ciq146 IDSA guideline recommending mupirocin nasal decolonisation (with or without chlorhexidine) for recurrent MRSA skin and soft tissue infections.
- Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the IDSA. Clin Infect Dis. 2014;59(2):e10–e52. doi:10.1093/cid/ciu296 IDSA SSTI guideline recommending topical mupirocin or retapamulin as first-line therapy for non-bullous impetigo and as part of decolonisation for recurrent abscesses.
- Popovich KJ, Aureden K, Ham DC, et al. SHEA/IDSA/APIC practice recommendation: strategies to prevent MRSA transmission and infection in acute-care hospitals: 2022 update. Infect Control Hosp Epidemiol. 2023;44(7):1031–1067. doi:10.1017/ice.2023.102 Updated SHEA/IDSA compendium recommending universal decolonisation with mupirocin and CHG in ICUs; high-quality evidence supporting this strategy.
- Thomas CM, Hothersall J, Willis CL, Simpson TJ. Resistance to and synthesis of the antibiotic mupirocin. Nat Rev Microbiol. 2010;8(4):281–289. doi:10.1038/nrmicro2278 Comprehensive review of mupirocin biosynthesis, mechanism of action at isoleucyl-tRNA synthetase, and mechanisms of resistance including plasmid-mediated mupA gene transfer.
- Patel JB, Gorwitz RJ, Jernigan JA. Mupirocin resistance. Clin Infect Dis. 2009;49(6):935–941. doi:10.1086/605495 Key review of mupirocin resistance epidemiology, distinguishing low-level (chromosomal) from high-level (plasmid-mediated) resistance and their clinical implications.
- World Health Organization. Global guidelines for the prevention of surgical site infection. 2nd ed. Geneva: WHO; 2018. WHO WHO systematic review supporting mupirocin nasal decolonisation with or without chlorhexidine body washes to reduce S. aureus SSIs in nasal carriers undergoing surgery.