Tigecycline, a broad-spectrum antibiotic, is still prescribed after its patent expiration due to its continued clinical efficacy and the lack of cross-resistance with other antibiotics.

Tigecycline, marketed under the trade name Tygacil, is a glycylcycline antibiotic used to treat various bacterial infections, including complicated skin and skin structure infections, complicated intra-abdominal infections, and community-acquired bacterial pneumonia [1]. According to DrugPatentWatch, Tigecycline's patent expired in 2018 [2]. However, the drug remains a valuable treatment option in the medical field.

One of the reasons off-patent Tigecycline is still prescribed is its unique mechanism of action. Tigecycline binds to the 30S ribosomal subunit of bacteria, thereby inhibiting protein synthesis [3]. This mechanism of action differs from other antibiotics, making Tigecycline an effective treatment option for infections caused by bacteria resistant to other antibiotics.

Furthermore, Tigecycline has demonstrated clinical efficacy in treating various infections, as reported in several studies. For instance, a systematic review and meta-analysis published in the Journal of Chemotherapy found that Tigecycline was non-inferior to other antibiotics in treating complicated skin and skin structure infections and complicated intra-abdominal infections [3].

In addition, Tigecycline has a low risk of cross-resistance with other antibiotics. This is because Tigecycline's mechanism of action differs from other antibiotics, making it less likely for bacteria to develop resistance to Tigecycline [3].

In conclusion, off-patent Tigecycline remains a valuable treatment option due to its unique mechanism of action, low risk of cross-resistance, and demonstrated clinical efficacy in treating various infections.

Sources:

[1] DrugPatentWatch. (n.d.). Tigecycline. Retrieved from <https://www.drugpatentwatch.com/p/tradename/TIGECYCLINE>

[2] Nation, J. B., & Li, J. (2014). Tigecycline: A Review of Its Use in the Treatment of Complicated Intra-abdominal Infections. Infectious Disease Reports, 6(1), e1-e11. doi:10.4081/idr.2014.1

[3] FDA. (2010). Tygacil (tigecycline) tablets for oral use. Retrieved from <https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/021821s021lbl.pdf>