β lactam antibiotic
Binds to penicillin binding protein (transpeptidase) and
prevents crosslinking of bacterial peptidoglycan
impairs cell wall synthesis

Converted to active form or nitroso free radical by
obligate anaerobes. Inhibits DNA synthesis. Causes DNA degradation

Inhibitor of bacterial 50S ribosomal subunit

Prevents protein synthesis

GIT– abdominal pain, N/V/D, pseudomembranous colitis, hepatitis
HAEM- agranulocytosis
CNS- confusion, seizure, encephalopathy
HYPERSENSITIVITY- rash, anaphylaxis

GIT– abdominal pain, N/V/D,
jaundice, pancreatitis
HAEM- leukopenia
CVS– T wave flattening, QT
prolongation
CNS– ataxia, seizures, insomnia, paraesthesia
HYPERSENSITIVITY– rash
OTHER– metallic taste

- Pseudomembranous colitis due to c.diff
- Contact dermatitis
- Metallic taste
- Anaphylaxis

Narrow-Spectrum
Natural Penicillin

Highly bactericidal, only
gram positives/anaerobes,
susceptible to betalactamases

Targets
GPC: Streptococci, Meningococcus
Listeria (GPB)
GNC: Neisseria, Clostridia
Treponemma (Spiral)

Synergistic effects with
aminoglycosides

Active against anaerobes (including clostridium, N.Gonorrhoea, N.Menigitidis, Bacterioides and Fusobacterium) and protozoa
(trichomonas, Giardia)

Aerobic G+ cocci including MRSA (except enterococci)

Anaerobic G- bacilli

Most aerobic G- bacilli are resistant including pseudomonas (except Capnocytophagia canimorus)