Overview
DESCRIPTION Oxacillin for Injection, USP is a semisynthetic penicillin antibiotic derived from 6-amino-penicillanic acid. It is the sodium salt in a parenteral dosage form. Each Pharmacy Bulk Package of Oxacillin for Injection, USP contains oxacillin sodium monohydrate equivalent to 10 grams of oxacillin. The sodium content is 57.30 mg [2.5 mEq] per gram oxacillin.
Mechanism of Action
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 to 30 minutes. Oxacillin sodium, with normal doses, has insignificant concentrations in the cerebrospinal and ascitic fluids. It is found in therapeutic concentrations in the pleural, bile, and amniotic fluids. Oxacillin Sodium is rapidly excreted 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. Oxacillin sodium binds to serum protein, mainly albumin.
Indications
- INDICATIONS AND USAGE Oxacillin is indicated in the treatment of infections caused by penicillinase producing staphylococci which have demonstrated susceptibility to the drug. Cultures and susceptibility tests should be performed initially to determine the causative organism and its susceptibility to the drug (See CLINICAL PHARMACOLOGY - Susceptibility Test Methods ). Oxacillin may be used to initiate therapy in suspected cases of resistant staphylococcal infections prior to the availability of susceptibility test results.
Common Doses
- 500 mg
- 50 mg
- 100 mg
- 25 mg
Dosage
DOSAGE AND ADMINISTRATION The intent of the pharmacy bulk package for this product is for preparation of solutions for IV infusion only. Bacteriologic studies to determine the causative organisms and their susceptibility to oxacillin should always be performed. Duration of therapy varies with the type of severity of infection as well as the overall condition of the patient; therefore, it should be determined by the clinical and bacteriological response of the patient. In severe staphylococcal infections, therapy with oxacillin should be continued for at least 14 days.
Contraindications
- CONTRAINDICATIONS A history of a hypersensitivity (anaphylactic) reaction to any penicillin is a contraindication.
Side Effects
- ADVERSE REACTIONS Body as a Whole The reported incidence of allergic reactions to penicillin ranges from 0.7 to 10 percent (see WARNINGS ). Sensitization is usually the result of treatment but some individuals have had immediate reactions when first treated. In such cases, it is thought that the patients may have had prior exposure to the drug via trace amounts present in milk and vaccines. Two types of allergic reactions to penicillins are noted clinically, immediate and delayed.
Interactions
- Drug Interactions Tetracycline, a bacteriostatic antibiotic, may antagonize the bactericidal effect of penicillin and concurrent use of these drugs should be avoided. Oxacillin blood levels may be increased and prolonged by concurrent administration of probenecid which blocks the renal tubular secretion of penicillins. Probenecid decreases the apparent volume of distribution and slows the rate of excretion by competitively inhibiting renal tubular secretion of penicillins.