Oxacillin is an antibiotic used to treat various bacterial infections. It is available as a generic product only, and is injected intravenously (by IV) or into a muscle (IM injection) every four to six hours. Although most people tolerate this medicine well, side effects are possible and may include nausea, diarrhea, and allergic reactions.
Oxacillin sodium is a prescription antibiotic licensed to treat a number of infections. Specifically, it is used for infections caused by staphylococci bacteria that produce penicillinase (an enzyme than can destroy penicillin). It is injected either into a vein (intravenous, or IV, injection) or into a muscle (intramuscular, or IM, injection).
Oxacillin is available only as a generic product and is made by various manufacturers (see Generic Oxacillin for more information).
Oxacillin is a penicillin antibiotic. Penicillins are a part of a larger group of medications known as beta-lactam antibiotics, which are named after the ring-like "lactam" structure of these antibiotics. Oxacillin works by stopping bacteria from making cell walls, which eventually causes the bacteria to die.
More specifically, oxacillin is a penicillinase-resistant penicillin. Some bacteria produce penicillinase, an enzyme that destroys the beta-lactam structure of penicillin (making penicillin and other similar antibiotics ineffective for treating infections due to such bacteria). Oxacillin is resistant to penicillinase.
However, such bacteria (notably, methicillin-resistant Staphylococcus aureus, or MRSA) have developed resistance against oxacillin and other penicillinase-resistant penicillins. Oxacillin is ineffective against MRSA.