Tigecycline : First Member of the Novel Glycylcycline Class of Extended-Spectrum Antibiotics

Tigecycline is the first member of a synthetic analogue of tetracycline, known as a glycylcyline. Like other tetracyclines, tigecycline is a broad spectrum bacteriostatic agent. It inhibits protein synthesis by binding to the bacterial 30S ribosomes. Tigecycline has activity against both gram-positive and gram-negative bacteria. It also has activity against many multidrug resistant organisms including methicillin-resistant Staphylococcus aureus (MRSA), Pencillin-resistant Step to coccus pneumonia (PRSP) Vancomycin resistant Enterococcus species (VRE) and extended- spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiellapneumoniae. Tigecycline was approved for use in the United States in 2005.It is currently indicated inpatients 18 year of age and older for the treatment of complicated skin and skin structure infections and intra-abdominal infections due to sensitive organisms. Tigecycline is available in vials of 50 mg for parenteral use under the brand name Tygacil. The recommended dose is 100 mg intravenously initially, followed by 50 mg every 12 hours for 5 to 14 days depending on the severity and site of the infection. The Food and Drug Administration had issued a black box warning due increased risk for death in patients who received tigecycline with certain severe infections. The increased mortality rate is associated with patient who treated for hospital-acquired pneumonia, particularly ventilator-associated pneumonia. The cause of excess deaths is uncertain, but it is likely that most deaths related to the progression of the infection. A reduced dosage is recommended for patients with severe underlying liver disease.