Augpac: Pharmacology: Pharmacodynamics: Mechanism of Action: The amoxicillin component of the formulation exerts a bactericidal action against many strains of gram-positive and gram-negative organisms. The clavulanic acid component has little or no antimicrobial action. It does, however, by inactivation of susceptible β-lactamase, protect amoxicillin from degradation by β-lactamase enzymes produced by penicillin-resistant strains of organisms.
Pharmacokinetics: The pharmacokinetics of amoxicillin and clavulanic acid are closely allied and neither are adversely affected by the presence of food in the stomach, and are stable in the presence of gastric acid. The oral bioavailability of amoxicillin and potassium clavulanate is approximately 90% and 75%, respectively.
Peak serum levels of both occur about 1-2 hrs after oral administration. Clavulanic acid has about the same plasma elimination half-life (1 hr) as that of amoxicillin (1-3 hrs). Amoxicillin and clavulanate potassium is eliminated primarily unchanged through the renal route (glomerular filtration and tubular secretion). Approximately 50-78% of amoxicillin and 25-40% of clavulanic acid are excreted unchanged in urine within the first 6 hrs after administration.
Microbiology: Clavulanic acid is an irreversible inhibitor of β-lactamases produced by Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, Haemophilus influenzae, Neisseria gonorrhoeae and Bacteroides fragilis (in vitro activity does not necessarily imply in vivo efficacy). Potassium clavulanate does not inactivate the chromosomally mediated (Sykes type 1 cephalosporinase) β-lactamases produced by Acinetobacter spp, Citrobacter spp, Enterobacter, indole positive Proteus, Providencia spp and Serratia marcescens.