Linezolid Dosage and Use for Skin and Skin Structure Infections
For skin and skin structure infections including MRSA, linezolid should be administered at 600 mg twice daily orally or intravenously for adults and 10 mg/kg every 8 hours for children under 12 years of age, with treatment duration of 7-14 days based on clinical response. 1, 2
Dosage Recommendations
Adults:
- Oral or IV: 600 mg every 12 hours 1, 3
- Duration: 7-14 days (individualized based on clinical response) 1
Children:
- Age >12 years: 600 mg PO/IV twice daily 1
- Age <12 years: 10 mg/kg PO/IV every 8 hours 1
- Tetracyclines should not be used in children <8 years of age 1
Clinical Indications
Uncomplicated Skin and Skin Structure Infections:
- Linezolid is recommended as a first-line oral agent for MRSA skin infections with strong evidence (recommendation 1A) 1
- Particularly effective when coverage for both β-hemolytic streptococci and CA-MRSA is desired 1
Complicated Skin and Skin Structure Infections:
- For hospitalized patients with complicated SSTI, linezolid (600 mg twice daily) is recommended as empirical therapy for MRSA pending culture results 1
- Clinical cure rates for complicated skin infections are approximately 90% 3
- Superior tissue penetration compared to vancomycin 2
Efficacy Evidence
- Linezolid demonstrates better clinical cure rates compared to vancomycin in skin and soft tissue infections (RR = 1.09; 95% CI, 1.03-1.16) 1, 2
- In MRSA infections specifically, linezolid shows better clinical cure rates (OR, 1.41; 95% CI, 1.03-1.95) 1
- For patients with vascular disease and lower-extremity complicated skin infections caused by MRSA, linezolid showed significantly higher clinical success rates (80.4%) compared to vancomycin (66.7%, p=0.02) 4
Monitoring and Safety Considerations
- Complete blood counts should be monitored weekly for treatments longer than 2 weeks due to risk of myelosuppression 2
- No dosage adjustment is needed for mild to moderate renal or hepatic impairment 2
- Most common adverse events are gastrointestinal disturbances 5
- Monitor for thrombocytopenia, which occurs more frequently with linezolid than with vancomycin 4
- Long-term use may lead to peripheral/optic neuropathy, lactic acidosis, and serotonin syndrome 2
Alternative Treatments for MRSA Skin Infections
When linezolid is not appropriate, alternatives include:
- Trimethoprim-sulfamethoxazole (TMP-SMX) (recommendation 1B) 1
- Tetracyclines (doxycycline or minocycline) (recommendation 1B) 1
- Clindamycin (600 mg IV or PO 3 times daily) 1
- Daptomycin (4 mg/kg/dose IV once daily) 1
- Vancomycin (15 mg/kg every 12 hours IV) 1
Special Populations
Pediatric Patients:
- Linezolid is effective and well-tolerated in children with MRSA infections 6
- In outpatient settings, clinical cure rates for MRSA skin infections in children treated with linezolid were 92.3% 6
- In inpatient settings, clinical cure rates for MRSA infections in children were 94.1% with linezolid versus 90.0% with vancomycin 6
Clinical Decision Algorithm
For outpatient treatment of suspected/confirmed MRSA skin infections:
- First-line: Oral linezolid 600 mg twice daily (adults) or age-appropriate dosing for children
- Alternatives: TMP-SMX, doxycycline, or minocycline
For hospitalized patients with complicated skin infections:
- Initiate IV linezolid 600 mg twice daily
- Consider switching to oral therapy when clinically stable
- Duration: 7-14 days based on clinical response
For patients with both MRSA and β-hemolytic streptococcal infections:
- Linezolid alone is sufficient (covers both pathogens)
- Alternative: TMP-SMX or tetracycline plus a β-lactam
For recurrent MRSA skin infections:
- Consider decolonization strategies along with linezolid therapy
- Implement hygiene measures and wound care education
Linezolid offers the advantage of excellent bioavailability, allowing for easy transition from intravenous to oral therapy with the same dosing, which may reduce length of hospital stay compared to agents like vancomycin 2.