Tigecycline is an antibiotic used to treat various bacterial infections, including complicated skin and intra-abdominal infections. The drug's patent expiration and subsequent generic entry into the market can significantly affect its cost. However, a patent extension for tigecycline has been granted, which may have implications for its pricing.

Patent extensions are granted to pharmaceutical companies to allow them additional time to profit from their inventions. This extension can delay the entry of generic competitors, thereby maintaining the brand-name drug's market monopoly and potentially keeping prices high.

According to DrugPatentWatch.com [1], tigecycline's patent expired in 2018, but an extension was granted, pushing the generic entry date to 2023. This extension means that the drug's manufacturer, Pfizer, can continue to exclusively sell the drug under the brand name Tygacil for an additional few years.

The patent extension for tigecycline can impact costs in several ways:

1. **Higher Prices**: With no generic competition, Pfizer can maintain Tygacil's price at a higher level. This can lead to increased healthcare costs for patients, hospitals, and insurance providers.

2. **Limited Access**: Higher prices can limit access to the drug for some patients, particularly those without adequate insurance coverage or those who must pay out-of-pocket.

3. **Incentive for Generic Development**: The patent extension provides an incentive for generic manufacturers to develop a generic version of tigecycline as soon as the patent expires. This competition can lead to lower prices in the long term.

In conclusion, the patent extension for tigecycline can affect its cost by maintaining higher prices and potentially limiting access to the drug. However, the entry of generic competitors in 2023 may lead to price decreases and increased accessibility.

**Sources:**
[1] <https://www.drugpatentwatch.com/patent/US5994124>