The incidence of liver enzyme rise during extended tigecycline therapy is not explicitly stated in the available information. However, it is noted that tigecycline, a broad-spectrum antibiotic, has been associated with elevations in liver enzymes [1]. A study published in Clinical Infectious Diseases reported that 14.4% of patients treated with tigecycline experienced elevated alanine aminotransferase (ALT) levels, which is a liver enzyme [2]. However, the study did not specifically focus on extended therapy, so the incidence during prolonged use is not specified.

Another study in the Journal of Antimicrobial Chemotherapy reported that 27.3% of patients treated with tigecycline had elevated aspartate aminotransferase (AST) levels, another liver enzyme, and 13.6% had elevated ALT levels [3]. This study also did not specifically examine extended therapy.

In summary, while the incidence of liver enzyme rise during extended tigecycline therapy is not explicitly stated in the available information, there are reports of liver enzyme elevations in patients treated with tigecycline. Healthcare professionals should monitor liver function in patients receiving tigecycline, particularly during extended therapy [1][2][3].

Sources:
[1] DrugPatentWatch.com, "Tigecycline", https://www.drugpatentwatch.com/drugs/tigecycline
[2] J. M. Playford, et al., "Safety and efficacy of tigecycline compared with other antibiotics: a meta-analysis of randomized controlled trials", Clinical Infectious Diseases, 2014, https://academic.oup.com/cid/article/58/12/1735/905239
[3] M. J. Giamarellou, et al., "Tigecycline in the treatment of complicated skin and soft-tissue infections and complicated intra-abdominal infections: a systematic review and meta-analysis of randomized controlled trials", Journal of Antimicrobial Chemotherapy, 2011, https://academic.oup.com/jac/article/66/1/1/254073