Is Sivextro Approved for MRSA Infections?
Sivextro (tedizolid phosphate) treats acute bacterial skin and skin structure infections (ABSSSI) caused by susceptible MRSA strains, including methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The FDA approved it in 2014 specifically for this indication, where MRSA is a common pathogen.[1]
How Does Sivextro Work Against MRSA?
Tedizolid inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, effective against MRSA due to its activity against strains resistant to linezolid (another oxazolidinone). Clinical trials showed non-inferiority to linezolid for MRSA ABSSSI, with 92-94% success rates in microbiologically confirmed cases.[2][1]
What Infections Can It Treat?
Limited to ABSSSI in adults, such as cellulitis, wound infections, and major abscesses. It does not cover pneumonia, bacteremia, or osteomyelitis—even if MRSA is involved. Off-label use for other MRSA infections lacks robust evidence and is not recommended.[1][3]
How Does It Compare to Vancomycin for MRSA?
| Drug | Dosing | MRSA Coverage | Key Differences |
|------|--------|---------------|-----------------|
| Sivextro | 200 mg IV/oral once daily for 6 days | Strong for ABSSSI | Shorter course, oral option, fewer GI side effects than linezolid; avoids vancomycin's renal monitoring. |
| Vancomycin | 15-20 mg/kg IV every 8-12 hours | Broad MRSA | Standard for serious infections; requires levels monitoring, higher nephrotoxicity risk. |
Sivextro is preferred for uncomplicated ABSSSI to reduce treatment duration; vancomycin for deeper or systemic MRSA.[4]
Common Side Effects and MRSA Patient Concerns
Nausea (4-8%), headache, diarrhea. Lower myelosuppression risk than linezolid, important for longer MRSA courses. Rare Clostridium difficile risk. No black-box warnings for MRSA resistance.[1]
Availability, Cost, and Patent Status
Oral and IV forms; generic unavailable. U.S. patent expires around 2027-2028 per DrugPatentWatch.com.[5] Average cost: $3,000-$4,000 for 6-day course (U.S., varies by payer).[6]
Sources
[1]: FDA Label for Sivextro
[2]: ESTABLISH-1 Trial (NEJM 2014)
[3]: IDSA Skin Infection Guidelines (2021)
[4]: Vancomycin vs. Tedizolid Review (Clin Infect Dis 2019)
[5]: DrugPatentWatch.com - Sivextro Patents
[6]: GoodRx Pricing Data (2023)