OXACILLIN- oxacillin sodium injection, powder, for solution
Sandoz Inc

For Intravenous Injection Only

In ADD-Vantage® Drug Delivery System

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.

DESCRIPTIONOxacillin for Injection, USP ADD-Vantage® is a semisynthetic antibiotic substance derived from 6-amino-penicillanic acid intended for intravenous administration only. It is the sodium salt in a parenteral dosage form. Each gram of Oxacillin Sodium contains approximately 2.5 mEq of sodium and is buffered with 20 mg dibasic sodium phosphate.

Oxacillin Sodium, C19 H18 N3 NaO5 S • H2 O, MW=441.43, is designated as 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)] and has the following structural formula:
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 µg/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.

MicrobiologyPenicillinase-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 and nonpenicillinase-producing strains of Staphylococcus aureus.

The penicillinase-resistant penicillins are active in vitro against a variety of other bacteria.

Susceptibility Plate TestingQuantitative methods of susceptibility testing that require measurement of zone diameters or minimal inhibitory concentrations (MIC’s) give the most precise estimates of antibiotic susceptibility. One such procedure has been recommended for use with discs to test susceptibility to this class of drugs. Interpretations correlate diameters on the disc test with MIC values. A penicillinase-