Amsubac Mechanism of Action

Pharmacology: Pharmacodynamics: Biochemical studies with cell-free bacterial systems have shown sulbactam to be an irreversible inhibitor of most important β-lactamases that occur in penicillin-resistant organisms. It possesses significant antibacterial activity only against Neisseriaceae, Acinetobacter calcoaceticus, Bacteroides sp, Branhamella catarrhalis and Pseudomonas cepacia. The potential for sulbactam sodium's preventing the destruction of penicillins and cephalosporins by resistant organisms was confirmed in whole organism studies using resistant strains, in which sulbactam sodium exhibited marked synergistic effects with penicillins and cephalosporins. Since sulbactam also binds to some penicillin-binding proteins, some sensitive strains are rendered more susceptible to the combination than to the β-lactam antibiotic alone.
The bactericidal component of the combination is ampicillin which, like benzyl penicillin, acts against sensitive organisms during the stage of active multiplication by the inhibition of biosynthesis of cell wall mucopeptide.
Ampicillin & Sulbactam Injection is effective against a wide range of gram-positive and gram-negative bacteria including: Staphylococcus aureus and epidermidis (including penicillin-resistant and some methicillin-resistant strains); Streptococcus pneumoniae, Streptococcus faecalis and other Streptococcus sp; Haemophilus influenzae and parainfluenzae (both β-lactamase-positive and -negative strains); Branhamella catarrhalis; anaerobes, including Bacteroides fragilis and related species; Escherichia coli, Klebsiella sp, Proteus sp (both indole-positive and indole-negative), Morganella morganii, Citrobacter sp and Enterobacter sp, Neisseria meningitidis and Neisseria gonorrhoeae.
Pharmacokinetics: Sulbactam sodium and ampicillin sodium diffuses readily into most body tissues and fluids in human. Penetration into brain and spinal fluid is low except when meninges are inflamed. High concentrations of sulbactam and ampicillin are achieved in the blood following IV or IM administration and both components have a half-life of approximately 1 hour. Most of the sulbactam sodium and ampicillin sodium is excreted unchanged in the urine.