Based on the provided information, there are certain scenarios where the dosage of Tigecycline may need adjustment when taken with other drugs.

Tigecycline, an antibiotic, is used to treat various bacterial infections [1][2]. According to the FDA label [3], Tigecycline should be administered via intravenous infusion, with a recommended dosage of 50 mg for the initial dose, followed by 25 mg every 12 hours.

The FDA label [3] also provides guidance on dosage adjustments when Tigecycline is used with other drugs. Specifically, it states that "no dosage adjustment is needed for patients with renal impairment or hepatic impairment." However, it also mentions that "Tigecycline is not recommended for patients with severe hepatic impairment" [3].

Furthermore, the FDA label [3] states that "Tigecycline is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) in vitro" and that "co-administration of Tigecycline with P-gp and/or BCRP inhibitors may increase Tigecycline plasma concentrations" [3]. Therefore, it is important to monitor patients when Tigecycline is co-administered with P-gp and/or BCRP inhibitors [3].

In summary, based on the provided information, Tigecycline dosage adjustment is not necessary for patients with renal or hepatic impairment, except for those with severe hepatic impairment. However, when Tigecycline is co-administered with P-gp and/or BCRP inhibitors, it is important to monitor patients due to the potential increase in Tigecycline plasma concentrations [3].

Sources:
[1] <https://www.drugpatentwatch.com/p/tradename/TIGECYCLINE>
[2] <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1426172/>
[3] <https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021821s026s031lbl.pdf>