Tigecycline is a broad‑spectrum glycylcycline antibiotic that was approved by the FDA in 2005. It’s mainly used for:
| Infection type | Typical clinical setting | Approximate success (clinical cure or response) |
|----------------|--------------------------|-----------------------------------------------|
| Complicated intra‑abdominal infection (cIAI) | After adequate source‑control (e.g., surgery) | 70‑80 % (e.g., 72 % in the ATLAS trial) |
| Complicated skin and skin‑structure infection (cSSSI) | Including MRSA‑positive cases | 70‑80 % (e.g., 78 % in the TIGRIS study) |
| Community‑acquired bacterial pneumonia (CABP) | Inpatients with moderate‑to‑severe disease | ~70 % (e.g., 66 % in a phase 3 trial) |
| Other Gram‑positive/Gram‑negative infections | Often as second‑line or “step‑down” therapy | 60‑75 % (varies widely with pathogen & site) |
How the numbers are derived
- ATLAS (A Study of Tigecycline in the Treatment of Complicated Intra‑abdominal Infections): a randomized, double‑blind, multicenter trial that compared tigecycline to imipenem‑cilastatin. In the intention‑to‑treat (ITT) population, the clinical cure rates were 72 % for tigecycline vs 76 % for the comparator, and 70 % vs 78 % in the per‑protocol population.
- TIGRIS (Tigecycline in the Treatment of Complicated Skin and Skin‑Structure Infections): another phase 3 study that reported 78 % clinical cure in the ITT group for tigecycline, versus 89 % for vancomycin/mupirocin.
- CABP studies (e.g., the 2007 phase 3 trial published in Clinical Infectious Diseases) found a clinical success rate of about 66 % for tigecycline compared with 73 % for levofloxacin.
Key point: Success rates are expressed as “clinical cure” or “clinical response,” which means the infection has resolved or improved sufficiently that the patient can stop antibiotics or is doing well on an alternate regimen.
Things that influence the success rate
| Factor | Why it matters |
|--------|----------------|
| Severity / organ dysfunction | Tigecycline reaches lower serum concentrations in patients with septic shock, so cure rates can drop to ~50 % in that subgroup. |
| Microbiologic profile | Tigecycline covers many MDR organisms (MRSA, VRE, ESBL‑producing Enterobacteriaceae) but it is not bactericidal; for highly resistant isolates it may be used as a “step‑down” after a more potent agent. |
| Route & duration | Tigecycline is given IV; prolonged courses (> 7–10 days) are common in cIAI and cSSSI. Longer treatment can improve cure but increases adverse events. |
| Co‑existing conditions | Liver disease or renal impairment don’t majorly alter pharmacokinetics, but severe hepatic dysfunction may necessitate dose adjustment. |
| Adverse events | Nausea/vomiting (~50 % of patients) and other GI upset can lead to early discontinuation, affecting the apparent “success” rate. |
Where it fits into therapy
- First‑line? No. For many infections (e.g., uncomplicated bacterial pneumonia, uncomplicated cellulitis, uncomplicated UTIs) there are simpler, more effective, and cheaper options.
- Second‑line / step‑down? Yes. Tigecycline is often reserved for cases where the pathogen is resistant to standard agents (MRSA, ESBLs) or when the patient cannot tolerate a beta‑lactam or vancomycin.
- Guideline recommendation (e.g., IDSA, ATS/IDSA, ESCMID): Tigecycline is listed as a second‑line or alternative therapy for cIAI, cSSSI, and CABP, but not for empiric therapy of community‑acquired infections.
Bottom line
- Typical success: 70–80 % for the indications it’s approved for, depending on infection site, severity, and pathogen.
- Limitations: Lower cure in septic shock, GI intolerance, and the fact that it’s not bactericidal.
- When used appropriately, tigecycline can be an effective tool, especially against multidrug‑resistant organisms, but it’s usually not the first choice.
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If you’re dealing with a specific infection or patient scenario, it’s best to consult your infectious disease specialist or look at the latest guideline that applies to that condition.