Cefixime is predominantly eliminated as unchanged drug in the urine. Glomerular filtration is considered the predominant mechanism. Metabolites of cefixime have not been isolated from human serum or urine.
Suprax® tablets (Cefixime) Summary of Product Characteristics, Sanofi-Aventis, updated November 2010

Approximately 50% of the absorbed dose is excreted unchanged in the urine in 24 hours. In animal studies, it was noted that cefixime is also excreted in the bile in excess of 10% of the administered dose. There is no evidence of metabolism of cefixime in vivo.
Suprax® (cefixime) US Prescribing Information, Lupin Pharmaceuticals INC, updated November 2011

In vitro studies using human liver microsomes have suggested that cefixime neither inhibited nor induced the metabolism of probe substrates via activity of cytochrome P450 metabolic enzymes CYP1A1/2, CYP2A6, CYP2B6, CYP2C8/9, CYP2C19, CYP2D6, CYP2E1 or CYP3A4. Cefixime would not be expected to cause clinically significant interactions with other drugs, which are metabolized by CYP450 enzymes.
Effect of cefixime and cefdinir, oral cephalosporins, on cytochrome P450 activities in human hepatic microsomes. Niwa T, Shiraga T, Hashimoto T, Kagayama A. Biol Pharm Bull. 2004; 27: 97-9.