Pharmacology Of Cefixime

Indication For use in the treatment of the following infections when caused by susceptible strains of the designated microorganisms: (1) uncomplicated urinary tract infections caused by Escherichia coli and Proteus mirabilis, (2) otitis media caused by Haemophilus influenzae (beta-lactamase positive and negative strains), Moraxella catarrhalis (most of which are beta-lactamase positive), and S. pyogenes, (3) pharyngitis and tonsillitis caused by S. pyogenes, (4) acute bronchitis and acute exacerbations of chronic bronchitis caused by Streptococcus pneumoniae and Haemophilus influenzae (beta-lactamase positive and negative strains), and (5) uncomplicated gonorrhea (cervical/urethral) caused by Neisseria gonorrhoeae (penicillinase- and non-penicillinase-producing strains).
Pharmacodynamics Cefixime, an antibiotic, is a third-generation cephalosporin like ceftriaxone and cefotaxime. Cefixime is highly stable in the presence of beta-lactamase enzymes. As a result, many organisms resistant to penicillins and some cephalosporins due to the presence of beta-lactamases, may be susceptible to cefixime. The antibacterial effect of cefixime results from inhibition of mucopeptide synthesis in the bacterial cell wall.
Mechanism of action Like all beta-lactam antibiotics, cefixime binds to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, causing the inhibition of the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that cefixime interferes with an autolysin inhibitor.
Absorption About 40%-50% absorbed orally whether administered with or without food, however, time to maximal absorption is increased approximately 0.8 hours when administered with food.
Volume of distribution Not Available
Protein binding 65% (concentration independent)
Metabolism Hepatic. Approximately 50% of the absorbed dose is excreted unchanged in the urine in 24 hours.
Route of elimination Not Available
Half life 3-4 hours (may range up to 9 hours). In severe renal impairment (5 to 20 mL/min creatinine clearance), the half-life increased to an average of 11.5 hours.
Clearance Not Available
Toxicity Symptoms of overdose include blood in the urine, diarrhea, nausea, upper abdominal pain, and vomiting.