Description
Cephalosporins
CEPHALOSPORINS
Isolated from fungus “Cephalosporinum
acremonium”.
Chemical structure comprises,
β – lactam ring and dihydrothiazide
Active nucleus : 7-aminocephalosporinic acid
Chemically similar to penicillin, so it shares the
mechanism of action and adverse effects with that.
Substitutions of chemical groups result in varying
pharmacologic properties and antimicrobial activities.
• Classification of Cephalosporins
• Pharmacokinetics of Cephalosporins
• Pharmcodynamics of Cephalosporins
• Spectrum Of Activity of Cephalosporins
• Therapeutic Uses of Cephalosporins
• ADRs of Cephalosporins
• Contraindications of Cephalosporins
Pharmcodynamics
Cephalosporins are bactericidal and have the same mode of action as other beta-lactam antibiotics (such as penicillins). Cephalosporins disrupt the synthesis of the peptidoglycan layer of bacterial cell walls. The peptidoglycan layer is important for cell wall structural integrity. The final transpeptidation step in the synthesis of the peptidoglycan is facilitated by transpeptidases known as penicillin binding proteins (PBPs). PBPs bind to the D-Ala-D-Ala at the end of muropeptides (peptidoglycan precursors) to crosslink the peptidoglycan. beta-lactam antibiotics mimic this site and competitively inhibit PBP cross linking of peptidoglycan.
- Subject:- pharmacology 3
- Course:- B.pharm (pharmacy),
- Semester:- 5th sem , sem :- 5
CEPHALOSPORINS
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CEPHALOSPORINS
Isolated from fungus “Cephalosporinum
acremonium”.
Chemical structure comprises,
β – lactam ring and dihydrothiazide
Active nucleus : 7-aminocephalosporinic acid
Chemically similar to penicillin, so it shares the
mechanism of action and adverse effects with that.
Substitutions of chemical groups result in varying
pharmacologic properties and antimicrobial activities.
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CLASSIFICATION
PARENTERAL ORAL
FIRST GENERATION Cephalothin *, Cephalexin,
1960 cefazolin cephradine, Cefadroxil
SECOND GENERATION Cefuroxime, Cefoxitin* Cefaclor, Cefuroxime
1970 Axetil, Cefotetan
THIRD GENERATION Cefotoxime, Cefixime, Cefpodoxime
1980 Ceftizoxime, proxetil, Cefdinir,
Ceftriaxone, Ceftibuten, Ceftamet
Ceftazidime, pivoxil
Cefoperazone
FOURTH GENERATION Cefepime, Cefpirome
1997-1998
FIFTH GENERATION Ceftobiprole -
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Pharmacokinetics
Orally not well absorption.
Parenterally good absorbed.
1st and 2nd generation cannot cross BBB where as 3rd
and 4th generation except cefoperazone can cross
BBB.
Not well metabolized.
Excretion through renal pathway except ceftriaxone
and cefoperazone which are excreted through biliary
pathway.
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Pharmcodynamics
Cephalosporins are bactericidal and have the same
mode of action as other beta-lactam antibiotics (such
as penicillins). Cephalosporins disrupt the synthesis of
the peptidoglycan layer of bacterial cell walls. The
peptidoglycan layer is important for cell wall structural
integrity. The final transpeptidation step in the
synthesis of the peptidoglycan is facilitated by
transpeptidases known as penicillin binding proteins
(PBPs). PBPs bind to the D-Ala-D-Ala at the end of
muropeptides (peptidoglycan precursors) to crosslink
the peptidoglycan. beta-lactam antibiotics mimic this
site and competitively inhibit PBP cross linking of
peptidoglycan.
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SPECTRUM OF ACTIVITY
CEPHALOSPORI MORE ACTIVE AGAINST MODERATELY ACTIVE
NS AGAINST
I generation Gm+ Ve Cocci Gm-ve cocci, Gm+ve bacilli &
Anaerobic Gm+ve cocci .
II generation Anaerobs , Gm-ve cocci & Gm+ Ve Cocci & Gm+ve bacilli
Gm-ve bacilli
III generation Anaerobs , Gm-ve cocci & Gm+ Ve Cocci & Gm+ve bacilli
Gm-ve bacilli
IV generation* Gm-ve cocci & Gm-ve bacilli Gm+ Ve Cocci
(resistant to III gen)
* No activity against anaerobes and Gm+ve bacilli
No action against ; Enterococcus faecalis, Methicillin resistant
Staphylococcus aureus (MRSA)& Listeria monocytogenes. www.remixeducation.in
CEPHALOSPORINS Gm+ve Gm-ve
I generation
II generation
III generation
IV generation : good Gm+ve and Gm-ve activity , and
good resistant against β – lactamase.
Therapeutic Uses
Respiratory tract infections (upper and lower RTIs)
Urinary tract infections
Bone and Joint infections (Septic arthritis,
osteomyelitis)
Mixed abdominal Infections
Septicemia
Hospital acquired nosocomial infections
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Therapeutic Uses
Ceftobiprole has been described as "fifth generation"
though acceptance for this terminology is not
universal.
Ceftobiprole (and the soluble prodrug medocaril) are
on the FDA fast-track.
Ceftobiprole has powerful Antipseudomonal
characteristics and appears to be less susceptible to
development of resistance.
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ADRs
Hypersensitivity reactions (anaphylactic shock, rashes
etc.)
Bleeding tendency (antibiotics of 2nd generation such as
cefamandol, cefotetan, cefmetazol and 3rd generation
such as cefoperazone and moxalactam cause
hypoprothrombinemia that results in bleeding)
GIT disturbance (Nausea, Vomiting, Diarrhea)
Disulfiram like reactions with some 2nd and 3rd
generation cephalosporins leading to tachy cardia,
flushing of face etc.
Intramuscular injection causes severe pain.
Intravenous injection sometimes cause phlebitis and
thrombophlebitis. www.remixeducation.in
Contraindications
Allergy
Bleeding disorder
Pregnancy
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Thank you
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