Cephalosporin drugs are beta lactam antibiotics that inhibit the cell wall of bacteria. Cephalosporin C was first isolated from a fungus named as Cephalosporium acremonium by Dr. Abraham in 1948. These are bactericidal antibiotics as they kill the micro-organisms when used at therapeutic dose.
Mode of Action:
The mechanism of action of cephalosporin drugs is similar to penicillin. They inhibit the enzymes that are necessary for the synthesis of cell wall of bacteria by combing with penicillin binding proteins (PBP). Remember their bactericidal activity does not depend upon the concentration of drug.
Classification of Cephalosporin:
Cephalosporins can be classified by different ways such as classification based upon;
- Chemical structure
- Resistance to beta lactamases
- Clinical pharmacology
But most renowned type of classification is based on generation. Cephalosporin drugs are divided into different generations depending upon their microbial spectrum.
- First generation
- Second generation
- Third generation
- Fourth generation
- Fifth generation
The optimum activity of all first generation cephalosporin drugs is against gram-positive bacteria such as staphylococci and streptococci. They also have little gram-negative spectrum.
The list of drugs is as follows.
1st Generation (Narrow Spectrum)
|Cefazolin||1-2gm||IV/IM||8||Streptococci b;Staphylococcus aureus. c||yes|
The drugs that come under second generation have more spectra against gram-negative bacteria (Haemophilus influenzae, Enterobacter aerogenes) in comparison to the first generation. Their gram positive spectrum is less than the first generation.
2nd Generation (Intermediate Spectrum)
|Cefamandole||1-2gm||IV/IM||4-6||Escherichia coli, Klebsiella, Proteus, Haemophilus influenzae, Moraxella catarrhalis.||yes|
Third generation cephalosporin drugs are broad spectrum and the effective against both gram positive and gram negative bacteria. However their optimum activity is against gram negative bacteria.
3rd Generation (Broad Spectrum)
|Cefotaxime||1-2gm||IV/IM||6-8||Pseudomonas aeruginosa e; Serratia; Neisseria gonorrhoeae; activity for S. aureus, Streptococcus pneumoniae,Enterobacteriaceae||yes|
These are extended spectrum antibiotics. They are resistant to beta lactamases.
4th Generation (Broad Spectrum)
|Cefipime||2gm||IV||12 hours||Their spectra is comparable to 3rd generation but they show more resistance to betalectamases||Yes|
These are extended spectrum antibiotics.
5th Generation (Extended Spectrum)
|Ceftaroline||600 mg||IV||12 hours||Pneumonia, skin and soft tissue infections|
|Ceftobiprole||500mg||IV||12 hours||Methicillin-resistant Staphylococcus aureus|
- The Merck Manual of Medical Information. Mark H. Beers et al., eds. 2nd Home Edition. Whitehouse Station, NJ: Merck; 2003.
- Tumah H. Fourth-generation cephalosporins: in vitro activity against nosocomial gram-negative bacilli. Chemotherapy. 2005 May;51(2-3):80-5.
- Brunton LL, Parker K, Blumenthal D, et al. The goodman and gilman’s manual of pharmacological therapeutics. McGraw-Hill Professional, 2007.
- Henry F. Chambers. Beta-Lactam & Other Cell Wall- & Membrane-Active Antibiotics. Basic & Clinical Pharmacology, edited by Bertram G. Katzung. McGraw Hill, USA, 2007.
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