DR fahd mushtaq

1. PENICILLIN &
CEPHALOSPORIN
Dr. Muhammad Fahd Mushtaq
M.Phil pharmacology (GCUF)

2. Penicillins
Penicillin was the first antibiotic to
be used clinically in 1941. It was
originally obtained from the fungus
Penicillium notatum.
Penicillin-binding proteins (PBP)
Methicillin-resistant Staphylococcus
aureus (MRSA)

3. • Natural penicillins
Penicillin G ,Penicillin V
Antistaphylococcal penicillins (penicillinase resistant)
• Nafcillin,Oxacillin, Cloxacillin, Dicloxacillin
Aminopenicillins
• Ampicillin, Amoxicillin
Antipseudomonal penicillins
• Carbenicillin, Mezlocillin, Piperacillin, Ticarcillin

4. • Mechanism of Action of Penicillin
Penicillin-binding proteins
Inhibition of transpeptidase
Production of autolysins
LPS

5. Antibacterial Spectrum
 Gram positive Cocci: Streptococci (except viridans, group D or enterococci)
are highly sensitive, so are many pneumococci. Staph. aureus,
though originally very sensitive.
 Gram negative cocci—Neisseria gonorrhoeae and N.
meningitidis are susceptible to PnG,
 Gram-positive bacilli—majority of B. anthracis,Corynebacterium
diphtheriae, and practically all Clostridia (tetani and others)
 gram-negative bacilli, Mycobacterium tuberculosis, rickettsiae,
chlamydiae, protozoa, fungi and viruses are totally insensitive to
PnG.

6. Bacterial Resistance

7. • Penicillinase Resistence of penicillin
 A.D.R’S
Local irritancy and direct toxicity
Hypersensitivity
Superinfection
Jarisch-Herxheimer reaction
Diarrhea & Nephritis
Neurotoxicity& Hematologic toxicities
Cation toxicity

8. • Clinical Uses
Streptococcal infections
Pneumococcal infections
Meningococcal infections
Gonorrhoea
Diphtheria
Tetanus and gas gangrene
Prophylactic uses
Rheumatic fever , Bacterial endocarditis, Agranulocytosis
patients

9. Cephalosporin
These 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).

10. 1st Generation
Cefadroxil, Cefazolin, Cephalexin ,Cephapirin ,Cephradine
Spectrum have high activity against gram-positive but weaker against gram-
negative bacteria.
• Streptococci (pyogenesas well as viridans), gonococci, meningococci, C.
diphtheriae, H. influenzae, clostridia and Actinomyces. Activity against
Klebsiella,Moraxella catarrhalis and E. col
2nd Generation
Cefaclor, Cefamandole, Cefmetazole, Cefonicid, Cefotetan, Cefoxitin, Cefprozil,
Cefuroxime, Cefuroxime axetil, Loracarbefa

11. Spectrum
• more active against gram- butegative organisms but They are weaker than the first generation
compounds against gram positive bacteria
• ampicillin-resistant H. influenzae, while retaining significant activity on gram-positive
cocci and certain anaerobes, but not B. fragilis.
3rd Generation
Cefdinir, Cefepime,Cefixime, Cefoperazone, Cefotaxime, Cefpodoxime proxetil Ceftazidime,
Ceftibuten, Ceftizoxime, Ceftriaxone, Carbapenems,Imipenem-cilastatin, Meropenem, Monobactam,
Aztreonam
• Spectrum have highly augmented activity against gram-negative All are
highly resistant to β-lactamases from gram-negative bacteria.However,
they are less active on gram-positive cocci and anaerobes

12. • Staph. Aureus, Ps. Aeruginos, S.typhi, B. fragilis, pneumococci, Pseudomonas
highly active against Enterobacteriaceae, streptococci and N. gonorrhea
 4th Greneation
Cefepime, Cefpirome
Spectrum high potency against Enterobacteriaceae and spectrum of
activity resembling the 3rd generation compounds.
• Cefepime highly resistant to β-lactamases, hence active against many
bacteria resistant to the earlier drugs. Ps. aeruginosa and Staph. aureus
are also inhibited but not MRSA. Due to high potency and extended
spectrum, it is effective in many serious infections like hospital-acquired
pneumonia, febrile neutropenia, bacteraemia, septicaemia. Higher
concentrations are attained in the CSF.

13. Cefpirome
This 4th generation cephalosporin is indicated for the treatment of serious
and resistant hospital-acquired infections including septicaemias, lower
respiratory tract infections,etc. Its zwitterion character permits better
penetration through porin channels of gram-negative bacteria. It is resistant
to many β-lactamases; inhibits type 1 β-lactamase producing
Enterobacteriaceae and it is more potent against grampositive and some
gram-negative bacteria

14. A.D.RS
Diarrhoea, Hypersensitivity reactions, Nephrotoxicity,
Neutropenia and thrombocytopenia
Clinical Uses
• As alternatives to penicillins, Respiratory, urinary and soft tissue
infections, Penicillinase producing staphylococcal infections
Septicaemias