Linezolid for MRSA Wound Infection: Dosing and Duration
Recommended Regimen
For adults with MRSA wound infections, administer linezolid 600 mg either intravenously or orally every 12 hours for 10–14 days. 1, 2
This recommendation applies specifically to complicated skin and soft tissue infections (cSSTI), which include surgical/traumatic wound infections, major abscesses, and infected ulcers. 1
Dosing Details
Adult Dosing
- Standard dose: 600 mg IV or PO every 12 hours 1, 2
- Route flexibility: Oral and IV formulations are interchangeable without dose adjustment, allowing early transition to oral therapy when clinically appropriate 2, 3
- No renal adjustment needed: The 600 mg every 12 hours dose remains unchanged regardless of renal function, including dialysis patients 3
Pediatric Dosing (if applicable)
- Children <12 years: 10 mg/kg IV or PO every 8 hours (maximum 600 mg per dose) 1, 2
- Children ≥12 years: 600 mg IV or PO every 12 hours (adult dosing) 1, 2
Treatment Duration by Infection Complexity
Uncomplicated Wound Infections
- Duration: 10–14 days for most complicated skin and soft tissue infections 1, 2
- The IDSA guidelines specify 7–14 days with individualization based on clinical response, but most uncomplicated cases complete 10–14 days 1, 2
Extended Duration for Complicated Cases
- Deep tissue involvement or osteomyelitis: Minimum 6–8 weeks, with consideration for additional 1–3 months of oral therapy 2, 4
- Septic arthritis: 3–4 weeks 2
- Bacteremia (uncomplicated): 7–14 days 2
- Bacteremia (complicated): 4–6 weeks 2
Critical Monitoring Requirements
Hematologic Monitoring
- Weekly complete blood counts are mandatory, particularly if treatment extends beyond 2 weeks 2, 4
- Monitor specifically for thrombocytopenia, anemia, and leukopenia 4
- Myelosuppression risk increases significantly with prolonged administration beyond 2 weeks 2
Neurologic Monitoring (for extended therapy >2 weeks)
- Monthly visual acuity and color discrimination testing 2, 4
- Consider prophylactic pyridoxine (vitamin B6) in patients with risk factors for peripheral neuropathy: diabetes, alcohol abuse, or malnutrition 2, 4
Important Clinical Considerations
Drug Interactions and Contraindications
- Avoid concomitant use with monoamine oxidase inhibitors or within 2 weeks of discontinuing MAOIs 2, 4
- Avoid in patients with: uncontrolled hypertension, pheochromocytoma, carcinoid tumor, thyrotoxicosis, bipolar depression, schizophrenia, or acute confusional states 2
- Risk of serotonin syndrome when combined with serotonergic agents 4
Efficacy Evidence
Linezolid demonstrates superior outcomes compared to vancomycin specifically for MRSA skin and soft tissue infections, with clinical cure rates of 88.6% versus 66.9% in culture-proven MRSA cases. 5 Among patients with vascular disease and lower-extremity MRSA infections, linezolid achieved 80.4% clinical success versus 66.7% with vancomycin. 6
Practical Advantages
- Oral bioavailability allows early hospital discharge and reduced IV catheter complications 7
- No therapeutic drug monitoring required unlike vancomycin 1
- Linezolid treatment reduces length of hospital stay and duration of IV therapy compared to vancomycin 7
Common Pitfalls to Avoid
- Do not reduce dosing frequency to every 24 hours—this fails to maintain adequate drug exposure for bactericidal activity 2
- Do not use linezolid empirically for catheter-related bloodstream infections—vancomycin or daptomycin are preferred first-line agents 2
- Recognize that linezolid is bacteriostatic (not bactericidal) against staphylococci, which is acceptable for most infections with adequate source control 4
- Prolonged use may encourage linezolid resistance in patients with chronic MRSA suppression or recurrent infections 4