Pharmacology for Dentistry

322 Section 9/ Chemotherapy

CEPHALOSPORINS

Cephalosporins are important bactericidal
broad spectrum β-lactam antibiotics used for
the treatment of septicaemia, pneumonia,
meningitis, urinary tract infections, peritonitis
and biliary tract infections. They are obtained
from fungus Cephalosporium acremonium and are
chemically related to penicillin. It consists of
beta lactam ring fused to a dihydrothiazine ring.

All cephalosporins act by inhibiting bac-
terial cell wall synthesis and are bacteri-
cidal. Also the autolytic enzymes in cell wall
may be activated leading to bacterial death.

They are widely distributed after
administration throughout body fluids.
Cephalosporins are mainly excreted by the
kidneys and dose should be altered in
patients with renal disease.

Cephalosporins are classified as in table
9.3.2.

Antibacterial activity: Cephalosporins

are active against a wide range of gram

positive and negative bacteria which

includes pneumococci, C. diphtheriae, E.

coli, N. gonorrhoeae, Proteus mirabilis, S.

typhi and paratyphi. The newer

cephalosporins are effective against

Pseudomonas aeruginosa. In dentistry,

cephalosporins is used only as alternative

to penicillin or amoxycillin in patients

who are allergic to penicillins. The second

generation cephalosporins are having

good activity against oral anaerobes and

are generally preferred in dentistry.

Pharmacokinetics

Cephalosporins are distributed in the

body after oral or parenteral administration

in same manner as penicillin is distributed.

The majority are not metabolized and are

eliminated by kidney.

Table 9.3.2: Classification of cephalosporins.

I. First generation cephalosporins

Cephalexin (SPORIDEX) 1-4 g QID

Cefazolin (AZOLIN) 1-4 g/d IM/IV

Cefadroxil (ODOXIL) 0.5-1 g BD

II. Second generation cephalosporins

Cefuroxime (CEFTUM) 250-500 mg BD

Cefaclor (KEFLOR) 250-500 mg TDS

Cefoxitin 1-2 g/day IM/IV

III.Third generation cephalosporins

Cefotaxime (OMNATAX) 1-2 g TDS, IM/IV

Ceftriaxone (CEFAXONE) 0.5-2 g OD IM/IV

Ceftizoxime (CEFIZOX) 1-3 g BD-TDS

Cefixime (BIOTAX-O) 200-400 mg OD-BD

Cefoperazone (CEFOMYCIN) 1-2 g TDS IM/IV

IV.Fourth generation (Newer) cephalosporins

Cefpirome (FORGEN) 1-2 g BD

Cefepime (KEFAGE) 1-2 g BD-TDS IV