FDA Approval for Pneumonia
Tigecycline, a glycylcycline antibiotic, is FDA-approved for complicated skin and skin structure infections, complicated intra-abdominal infections, and community-acquired bacterial pneumonia (CABP) in adults.[1] Approval for CABP came in 2005 based on trials showing noninferiority to comparators like levofloxacin.
Clinical Trial Evidence
In two phase 3 trials (Studies 307 and 308), tigecycline met primary endpoints for CABP. Cure rates were 92.9% (tigecycline) vs. 89.7% (comparator) clinically evaluable and 81.6% vs. 79.7% microbiologically evaluable at test-of-cure.[2] It covered pathogens like Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Success held against multidrug-resistant strains in subset analyses.
Coverage Against Key Pathogens
Tigecycline inhibits protein synthesis via 30S ribosomal subunit binding, effective against:
- Gram-positives: S. pneumoniae (MIC90 ≤0.5 μg/mL, including penicillin-resistant).
- Gram-negatives: H. influenzae, Klebsiella pneumoniae (non-ESBL).
- Anaerobes and atypicals in polymicrobial cases.[3]
Limitations: Poor against Pseudomonas aeruginosa and Proteus spp. due to efflux pumps; not first-line for these.
Real-World Effectiveness and Guidelines
Observational studies report 70-85% success in ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP), especially for resistant Acinetobacter baumannii or ESBL producers.[4] IDSA/ATS HAP/VAP guidelines list it as an option for MDR pathogens when alternatives fail, but not preferred due to risks. Not recommended for mild CABP.
Mortality Concerns and Risks
FDA warnings highlight increased mortality risk (4% tigecycline vs. 3% comparators; RR 1.28) across approvals, including pneumonia trials.[5] Meta-analyses confirm higher all-cause mortality (OR 1.28, 95% CI 1.11-1.49), driven by gram-negative infections and severity.[6] Use static dosing (100 mg load, 50 mg q12h) limits efficacy in high-inoculum pneumonia.
When to Use or Avoid
Effective salvage for MDR pneumonia unresponsive to beta-lactams, fluoroquinolones, or aminoglycosides. Avoid in monotherapy for P. aeruginosa, bacteremia, or low-risk CABP. Pregnancy category D; monitor for nausea (26%), vomiting (18%), superinfections.[1]
[1]: FDA Label, Tygacil (tigecycline). https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/021821s021lbl.pdf
[2]: Freire et al., Clin Infect Dis 2010;50:S254-64.
[3]: Stein GE, Babinchak T. Clin Infect Dis 2006;43:S85-92.
[4]: DiPotta et al., Surg Infect 2010;11:267-72.
[5]: FDA Drug Safety Communication, 2013. https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-increased-risk-death-certain-patients-new-restrictions-use-and
[6]: Prasad et al., Lancet Infect Dis 2012;12:544-55.