These antibiotics have low toxicity for the host, considering their broad antibacterial spectrum. They have the active nucleus of beta-lactam ring which results in a variety of antibacterial and pharmacologic characteristics when modified mainly by substitution at 3 and 7 positions.

Their antibacterial activities result from the inhibition of mucopeptide synthesis in the cell wall.

They are widely used to treat gonorrhea, meningitis, pneumococcal, staphylococcal and streptococcal infections.

The cephalosporin class of antibiotics is usually divided into generations by their antimicrobial properties. Three generations of cephalosporins are recognized and the fourth has been grouped.

Each newer generation of cephalosporins has broader range of activity against gram-negative organisms but a narrower range of activity against gram-positive organisms than the preceding generation.

The newer agents have much longer half-lives resulting in the decrease of dosing frequency.

Accordingly, the third-generation cephalosporins can penetrate into tissues well, and thus antibiotic levels are good in various body fluids.

GENERATIONS:

FIRST GENERATION CEPHALOSPORINS

- Cefadroxil

- Cephalexin

- Cephradine

SECOND GENERATION CEPHALOSPORINS

- Cefaclor

- Cefuroxime Axtel

- Cefprozil

- Loracarbef

THIRD GENERATION CEPHALOSPORINS

- Cefixime

- Cefpodoxime proxetil

- Ceftibuten

- Cefdinir

- Ceftriaxone

FOURTH GENERATION

Cefepime (Maxipime) is considered a fourth generation cephalosporin due to it’s intrinsic antimicrobial properties. Fourth generation cephalosporins are projected to have many attributes including:

extended spectrum of activity for gram negative and gram positive organisms (different from third generation cephalosporins)

minimal beta-lactamase activity due to rapid periplasmic penetration and high penicillin-binding protein (PBP) access

spectrum of activity to include gram negative organisms with multiple drug resistance patterns (Enterobacter and Klebsiella)

Cefepime is currently available in an injectable form for use in adults and children > 12 years old. Cefepime is not available in an oral form