Clinical Medicine Insights: Therapeutics

Tigecycline is a first-in-class glycylcycline, broad-spectrum, intravenous antibacterial developed to overcome the two major mechanisms of tetracycline resistance (ribosomal protection and efflux). The drug has been approved in US for community-acquired bacterial pneumonia in adults. In vitro, tigecycline had good activity against a range of Gram-positive, Gram-negative and atypical community-acquired respiratory tract pathogens implicated in community-acquired pneumonia (CAP), including community-acquired Staphylococcus aureus, penicillin-resistant Streptococus pneumoniae and multidrug-resistant Enterobacteriaceae. Nonetheless, tigecycline shows in vitro low activity against against P. aeruginosa. Tigecycline provides high intrapulmonary concentrations that exceed the MIC90 of most of these respiratory pathogens. The combined results of two well designed, phase III studies demonstrated that tigecycline 100 mg initially, followed by 50 mg every 12 hours for 7–14 days was not inferior to recommended dosages of levofloxacin in the treatment of hospitalized patients with CAP. Clinical cure rates were 89.7% versus 86.3% in the clinically evaluable population and 81.0% versus 79.7% in the clinical modified intent-to-treat population. Tigecycline represents an appropriate choice for empirical monotherapy in the treatment of CAP, mainly in patients with risk factors for infections due to resistant bacteria.