Pharmacology: Pharmacodynamics: Clavulanic acid enhances the antibacterial spectrum of amoxicillin by rendering most Beta-lactamase-producing isolates susceptible to the drug. In clinical trials amoxicillin/Clavulanic acid is clinically and bacteriologically superior to amoxicillin alone and at least as effective as numerous other comparative agents, such as orally administered cephalosporin. The antibacterial activity of amoxicillin/Clavulanic acid has been well established. Clavulanic acid alone possesses only weak anti-bacterial activity, except against Legionella spp., and certain strains of Branhamella catarrhalis, B. fragilis and Neisseria gonorrhoeae. The in-vitro synergy of clavulanic acid combined with amoxicillin has been confirmed in vivo in numerous experimental infections in animals. The combination of amoxicillin with clavulanic acid appears to suppress the development of resistance under experimental conditions.
Pharmacokinetics: Combining Clavulanic acid with amoxicillin causes no appreciable alteration of the pharmacokinetics of either drug compared with their separate administration. After oral administration, both components achieve maximum plasma concentrations in about 1 hour and these concentrations show a direct relationship to the dose administered. The absolute bioavailability of Clavulanic acid is about 60%. Absorption is unaffected by concomitant administration of food, milk etc. Clavulanic acid has a volume of distribution of about 25% of body weight and is about 22% protein bound in vitro. Both Clavulanic acid and amoxicillin possess a mean elimination half-life of about 1 hour and a mean total clearance of about 25L/h healthy subjects. The main route of elimination is via the urine.