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Cephalosporins:- PPT / PDF

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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