Beta lactam antibiotics

1. BETA LACTAM
ANTIBIOTICS
Presented by
Grandhi Sandeep Ganesh
Dept. Of Pharmacology
Shri Vishnu College of Pharmacy (Autonomous)
Affiliated to Andhra Univ., Visakhapatnam; Approved by AICTE and PCI, New Delhi, and recognised by APSCHE
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2. BETA LACTAM ANTIBIOTICS
These are the antibiotics contains
BETA LACTAM ring in their
structure
The two major groups containing
beta lactam ring are
Penicillins
Cephalosporins
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3. PENICILLINS
Penicillin was discovered by scientist Alexander Fleming
 penicillin is obtained from Penicillium notatum or P. chrysogenum
It was discovered in 1928
Penicillin was the first antibiotic to be used clinically in 1941
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4. Interfere with synthesis of bacterial cell wall
Usually the bacterial cell wall is composed of peptidoglycan
N- acetylmuramic acid
N- acetylglucosamine
Peptidoglycan residues are linked together and UDP is split off
Final step is cleavage of terminal D-alanine of the peptide by transpeptidase,
process known as transpeptidation
This cross linking provides greater strength of bacterial cell wall
Beta lactams inhibit the transpeptidase so that cross linking does not take
place
This results in cell wall deficient forms are produced and lysis of bacteria
takes place
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MECHANISM OF ACTION

5. MECHANISM OF ACTION
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CLASSIFICATION

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PENICILLIN-G
Penicillin-G is a narrow spectrum
antibiotic
Its activity is limited primarily to gram-
positive bacteria, few gram negative
ones and anaerobes.
It is the drug of first choice for many
infections

8. Local irritancy and direct toxicity: Pain at i.m. injection site, nausea
on oral ingestion
Toxicity to the brain may be manifested as mental confusion,
muscular twitching, convulsions and coma, when very large doses are
injected through i.v route
 Accidental i.v. injection of procaine penicillin produces CNS
stimulation, hallucinations and convulsions
Hypersensitivity: rash, itching, urticaria and fever. Wheezing,
angioneurotic edema, serum sickness and exfoliative dermatitis
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ADVERSE EFFECTS

9. In rare cases,
Swelling of the tongue, throat and lips
Respiratory symptoms such as difficulty breathing, coughing, chest
tightness, wheezing
Light-headedness
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ADVERSE EFFECTS

10. Semisynthetic penicillins are produced by chemically combining
specific side chains in place of benzyl side chain of PnG
The aim of producing semisynthetic penicillins has been to overcome
the shortcomings of PnG
 Poor oral efficacy.
Susceptibility to penicillinase.
 Narrow spectrum of activity.
Hypersensitivity reactions
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SEMISYNTHETIC PENICILLINS

11. ACID-RESISTANT: Phenoxymethyl penicillin (Penicillin V)
It differs from PnG only in that it is acid stable. Oral absorption is better; peak
blood level is reached in 1 hour and plasma t½ is 30–60 min.
PENICILLINASE-RESISTANT PENICILLINS: Methicillin,
Cloxacillin, Dicloxacillin
These congeners have side chains that protect the β-lactam ring from attack by
staphylococcal penicillinase
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SEMISYNTHETIC PENICILLINS

12. AMINOPENICILLINS: Ampicillin
It is active against all organisms sensitive to PnG. In addition, many
gram-negative bacilli, e.g. H. influenzae, E. coli, Proteus, Salmonella
Shigella and Helicobacter pylori are inhibited.
USES
Urinary tract infections
Respiratory tract infections
Meningitis
Gonorrhoea
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EXTENDED SPECTRUM PENICILLINS

13. Carboxypenicillins: Carbenicillin
The special feature of this penicillin congener is its activity
against Pseudomonas aeruginosa and indole positive Proteus which are
not inhibited by PnG or aminopenicillins.
Ureidopenicillins: Piperacillin
This antipseudomonal penicillin is about 8 times more active than
carbenicillin. It has good activity against Klebsiella, It is frequently
employed for treating serious gram negative infections in
neutropenic/immunocompromised patients
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EXTENDED SPECTRUM PENICILLINS

14. Beta-lactamase inhibitors can block the activity of beta-lactamase
enzymes and prevents the degradation of beta-lactam antibiotics
β-lactamases are a family of enzymes produced by many gram-
positive and gram-negative bacteria that inactivate β-lactam antibiotics
by opening the β-lactam ring
Clavulanic acid
Obtained from Streptomyces clavuligerus, it has a β-lactam ring
but no antibacterial activity of its own. It inhibits a wide variety of β-
lactamases produced by both gram-positive and gram-negative bacteria
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BETA-LACTAMASE INHIBITORS

15. Bacterial meningitis : benzylpenicillin
Bone and joint infections : flucloxacillin
Skin and soft tissue infections : benzylpenicillin, flucloxacillin
Otitis media : amoxicillin
 Bronchitis : amoxicillin
Pneumonia : amoxicillin
Urinary tract infections :amoxicillin
Gonorrhea : amoxicillin
Syphilis : procaine benzylpenicillin
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USES

16. Cephalosporins are a group of
semisynthetic antibiotics derived
from ‘cephalosporin-C’ obtained
from a fungus Cephalosporium
The nucleus consists of a β-lactam
ring fused to a dihydrothiazine
ring,(7-aminocephalosporanic acid)
All cephalosporins are bactericidal
and have the same mechanism of
action as penicillin
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CEPHALOSPORINS

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CLASSIFICATION

18. Pain after i.m. injection occurs with many cephalosporins
Diarrhoea
Hypersensitivity reactions Rashes are the most frequent manifestation,
but anaphylaxis, angioedema, asthma and urticaria have also occurred
in rare cases
Nephrotoxicity
Neutropenia and thrombocytopenia are rare adverse effects
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ADVERSE EFFECTS

19. As alternatives to penicillins for upper respiratory and cutaneous
infections
urinary and soft tissue infections caused by gram-negative organisms
Septicaemias caused by gram-negative organisms: cefuroxime,
cefotaxime
 pneumonia
Meningitis: ceftriaxone, cefotaxime
 biliary tract infection
 urinary tract infection
 sinusitis: cefadroxil
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USES

20. MONOBACTAMS
The main monobactam is aztreonam , which is resistant to most β-
lactamases effective only against Gram-negative aerobic bacilli
CARBAPENEMS
Imipenem, an example of a carbapenem, acts in the same way as the
other β-lactams being active against many aerobic and anaerobic
Gram-positive and Gram-negative organisms
It is resistant to most β-lactamases, inhibits penicillinase producing
staphylococci
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OTHER BETA LACTAM ANTIBIOTICS

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you
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