Flucloxacillin is an antibiotic and is used to treat infections caused by susceptible Gram-positive bacteria. It is active against beta-lactamase-producing organisms such as Staphylococcus aureus, which would otherwise be resistant to most penicillins. These bacteria are responsible for antibiotic-resistance amongst certain skin, chest, bone and joint infections and soft tissue infections. This medicine is well absorbed in the stomach therefore is best taken on an empty stomach unlike most other antibiotics.

Flucloxacillin acts by inhibiting the synthesis of bacterial cell walls. The cell walls of bacteria are vital for their survival. They keep unwanted substances from entering their cells and stop the contents of their cells from leaking out. Flucloxacillin impairs the bonds that hold the bacterial cell wall together. This allows holes to appear in the cell walls and kills the bacteria.

It is active penicillin resistant bacteria called staphylococci, becuase it is not broken down by the penicillinase enzyme (which breaks down other types of penicillin) that is produced by this group of bacteria.

Formal Chemical Name (IUPAC)
(2S,5R,6R)-6-(3-(2-chloro-6-fluorophenyl)-5-methylisoxazole-4-carboxamido)-3,3-dimethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid

References

http://en.wikipedia.org/wiki/Flucloxacillin