Based on the information available, there is some evidence to suggest that extended use of tigecycline, a broad-spectrum antibiotic, may have an impact on liver enzyme counts. However, it's important to note that the relationship between tigecycline and liver enzymes is not fully understood and requires further study.

A study published in the Journal of Antimicrobial Chemotherapy found that tigecycline use was associated with elevated levels of liver enzymes, specifically alanine aminotransferase (ALT) and aspartate aminotransferase (AST) [1]. The study analyzed data from 131 patients who received tigecycline and found that 23.7% of them had elevated liver enzymes.

Moreover, DrugPatentWatch.com, a website that provides information on drug patents, lists liver function tests as a potential adverse effect of tigecycline [2]. The website cites the drug's prescribing information, which states that "increases in liver function tests have been observed in clinical trials" [2].

However, it's important to note that the relationship between tigecycline and liver enzymes is not straightforward. A study published in the Journal of Clinical Pharmacy and Therapeutics found that tigecycline use was not associated with significant changes in liver enzyme levels [3]. The study analyzed data from 52 patients who received tigecycline and found no significant differences in liver enzyme levels before and after treatment.

In summary, while there is some evidence to suggest that extended use of tigecycline may be associated with changes in liver enzyme counts, the relationship is not fully understood and requires further study. Healthcare providers should monitor liver function tests in patients receiving tigecycline and use caution when prescribing the drug for extended periods.

Sources:

1. <https://academic.oup.com/jac/article/61/5/1151/840837>
2. <https://www.drugpatentwatch.com/drugs/tigecycline>
3. <https://onlinelibrary.wiley.com/doi/abs/10.1111/jcpt.12133>