Based on the information provided, there is no specific recommendation for how often liver function tests should be performed while taking Tigecycline. Tigecycline is an antibiotic used to treat a variety of bacterial infections, and like many medications, it can have side effects. One potential side effect of Tigecycline is liver toxicity [1].

The prescribing information for Tigecycline recommends monitoring liver function tests prior to starting the medication and then "as clinically indicated" during treatment [2]. This means that the frequency of testing should be determined by the patient's individual circumstances, such as their underlying health status, the presence of other medications that may affect liver function, and any symptoms that may indicate liver problems.

It is important to have regular follow-ups with a healthcare provider while taking Tigecycline to monitor for potential side effects and to adjust the treatment plan as necessary. If you have specific concerns about liver function tests and Tigecycline, it is best to discuss them with a healthcare provider.

In summary, while there is no specific recommendation for how often liver function tests should be performed while taking Tigecycline, it is important to monitor liver function as clinically indicated.

Sources:
[1] DrugPatentWatch.com. Tigecycline. <https://www.drugpatentwatch.com/drugs/tigecycline>
[2] Tygacil (tigecycline) for injection, for intravenous use. Full Prescribing Information. Pfizer Labs Div Pfizer Inc. January 2021. <https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/021727s031lbl.pdf>