OXACILLIN - oxacillin sodium injection, powder, for solution 
Sagent Pharmaceuticals
SAGENT™
Rx only
To reduce the development of drug-resistant bacteria and maintain the effectiveness of Oxacillin for Injection and other antibacterial drugs, Oxacillin for Injection should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.
DESCRIPTION
Oxacillin for Injection, USP is a semisynthetic penicillin antibiotic derived from the penicillin nucleus, 6-amino-penicillanic acid. It is resistant to inactivation by the enzyme penicillinase (beta-lactamase). It is the sodium salt in parenteral dosage form for intramuscular or intravenous use. Each vial of Oxacillin for Injection, USP contains oxacillin sodium monohydrate equivalent to 1 gram or 2 grams of oxacillin. The sodium content is 63.77 mg [2.77 mEq] per gram oxacillin. The product is buffered with 20 mg dibasic sodium phosphate per gram oxacillin. Oxacillin for Injection, USP is a white to off-white powder filled in clear glass vials. Dilute solutions are essentially clear and colorless.
OXACILLIN SODIUM

4-Thia-1-azabicyclo [3.2.0]heptane-2-carboxylic acid, 3,3-dimethyl-6-[[(5-methyl-3-phenyl-4-isoxazolyl) carbonyl] amino]-7-oxo-monosodium salt, monohydrate, [2S(2α,5α,6β)].
CLINICAL PHARMACOLOGY
Intravenous administration provides peak serum levels approximately 5 minutes after the injection is completed. Slow I.V. administration of 500 mg gives a peak serum level of 43 mcg/mL after 5 minutes with a half-life of 20-30 minutes.
The penicillinase-resistant penicillins bind to serum protein, mainly albumin. The degree of protein binding reported for oxacillin is 94.2% ± 2.1%. Reported values vary with the method of study and the investigator.
The penicillinase-resistant penicillins vary in the extent to which they are distributed in the body fluids. With normal doses, insignificant concentrations are found in the cerebrospinal fluid and aqueous humor. All the drugs in this class are found in therapeutic concentrations in the pleural, bile, and amniotic fluids.
The penicillinase-resistant penicillins are rapidly excreted primarily as unchanged drug in the urine by glomerular filtration and active tubular secretion. The elimination half-life for oxacillin is about 0.5 hours. Nonrenal elimination includes hepatic inactivation and excretion in bile.
Probenecid blocks the renal tubular secretion of penicillins. Therefore, the concurrent administration of probenecid prolongs the elimination of oxacillin and, consequently, increases the serum concentration.
Intramuscular injections give peak serum levels 30 minutes after injection. A 250 mg dose gives a level of 5.3 mcg/mL while a 500 mg dose peaks at 10.9 mcg/mL. Intravenous injection gives a peak about 5 minutes after the injection is completed. Slow IV dosing with 500 mg gives a 5 minute peak of 43 mcg/mL with a half-life of 20 to 30 minutes.
Microbiology
Penicillinase-resistant penicillins exert a bactericidal action against penicillin susceptible microorganisms during the state of active multiplication. All penicillins inhibit the biosynthesis of the bacterial cell wall.
The drugs in this class are highly resistant to inactivation by staphylococcal penicillinase and are active against penicillinase producing strains of Staphylococcus aureus. The penicillinase-resistant pe