Cefepime is a semi-synthetic, fourth-generation, broad spectrum, cephalosporin antibiotic for parenteral administration. Cefepime like all other Beta Lactams inhibit the cell wall synthesis and therby brings bactericidal effect. It also acts by binding to the Penicillin binding proteins which are located on the bacterial cell wall. Cefepime binds to these PBP and also exerts its action.
Amikacin is an Aminoglycoside. All the aminoglycosides acts in two steps: (a) Transport of the aminoglycoside through the bacterial cell wall and cytoplasmic membrane. (b) Binding to ribosomes resulting in inhibition of protein symthesis. Once inside the bacterial cell, it binds to 30S and 50S subunit and freeze initiation of protein slmthesis. Binding of aminoglycoside to 30S-50S juncture causes distortion of mRNA codon recognition resulting in misreading of the code: and peptides of abnormal lengths are produced.
Therefore, the main purpose behind combining the two drugs is to provide a broad spectrum empiric regimen Combination therapy includes agents from different antibiotic classes to avoid antagonism of therapeutic mechanisms.