Tigecycline

Tigecycline (INN) (IPA: ) is an glycylcycline antibiotic developed and marketed by Wyeth under the brand name Tygacil. It was given a U.S. Food and Drug Administration (FDA) fast-track approval and was approved on June 17, 2005. It was developed in response to the growing prevalence of antibiotic resistance in bacteria such as Staphylococcus aureus.

Pharmacology
This antibiotic is the first clinically-available drug in a new class of antibiotics called the glycylcyclines. It is structurally similar to the tetracyclines in that it contains a central four-ring carbocyclic skeleton and is actually a derivative of minocycline. Tigecycline has a substitution at the D-9 position which is believed to confer broad spectrum activity. The drug inhibits the bacterial 30S ribosome and is bacteriostatic.

Indications
Tigecycline is active against many Gram-positive bacteria, Gram-negative bacteria and anaerobes – including activity against methicillin-resistant Staphylococcus aureus (MRSA). It has no activity against Pseudomonas spp. or Proteus spp. The drug is licenced for the treatment of skin and soft tissue infections as well as intra-abdominal infections.

Dosing
Tigecycline is given by slow intravenous infusion (30 to 60 minutes). A single dose of 100 mg is given first, followed by 50 mg every twelve hours after that. Patients with impaired liver function need to be given a lower dose. No adjustment is needed for patients with impaired kidney function. It is not licensed for use in children. There is no oral form available.

Side Effects
The most common side effects of tigecycline are diarrhea, nausea and vomiting. Nausea and vomiting is mild or moderate and usually occurs during the first two days of therapy. Other side effects include pain at the injection site, swelling and irritation; increased or decreased heart rate and infections. As tigecycline is similar to the tetracycline antibiotics,they have similar side effects such as increased sensitivity to sunlight. Also avoid use in children and pregnancy, due to its affects on teeth and bone. As with other antibiotics, overgrowth of organisms that are not susceptible to tigecycline can occur.