Generic Name

Mupirocin

Mechanism

• Mupirocin selectively inhibits isoleucyl‑tRNA synthetase in gram‑positive bacteria.
• This blocks protein synthesis, leading to rapid bacterial death.
• The drug penetrates well into skin and respiratory mucosa, concentrating at the site of infection.

Pharmacokinetics

• Topical and intranasal formulations have negligible systemic absorption.
• Very low plasma levels (≤ 10 ng/mL) – no significant hepatotoxicity, nephrotoxicity, or central‑nervous‑system effects.
• Elimination primarily via the skin; metabolism not clinically relevant.

Indications

• Cutaneous staphylococcal infections: impetigo, folliculitis, erysipelas, superficial abscesses.
• Intranasal decolonization of *Staphylococcus aureus* (including MRSA); primary prophylaxis in transplant or ICU settings.
• Short‑course treatment of superficial *S. aureus* infections and coagulase‑negative staphylococcal infections.

Contraindications

• Hypersensitivity to mupirocin or any component.
• Use cautiously in patients with contact dermatitis or known skin allergies.
• Avoid prolonged use (> 10 days) on large skin areas to reduce resistance emergence.

Dosing

• For children, use the same regimen but observe for local irritation or rash.
• Do not exceed recommended frequency; higher concentrations may not improve efficacy and increase dermatitis risk.

Adverse Effects

• Local: redness, itching, burning, contact dermatitis, rash.
• Systemic: rarely, hypersensitivity reactions (urticaria, anaphylaxis).
• Rare: fungal overgrowth (candida) from prolonged use.

Monitoring

• Usually none required.
• In infants or immunocompromised patients, watch for skin reactions and persistence of infection.

Clinical Pearls

• Use it first‑line for culture‑confirmed *S. aureus* skin infections; it remains highly effective against MRSA.
• Avoid in patients with known skin eczema—contact dermatitis can delay healing.
• Limit intranasal therapy to < 10 days to prevent resistance.
• Combine with systemic antibiotics only if deep or invasive infection is present; topical mupirocin covers surface organisms but not systemic disease.
• Beware of misinterpreting a negative nasal swab as “non‑carrier”; a second culture after therapy may be needed to confirm decolonization.
• In healthcare settings, consider prophylactic mupirocin for MRSA‑colonized patients undergoing surgeries or central‑line placements.

*For detailed prescribing updates or institutional protocols, consult your local formularies and microbiology lab susceptibilities.*