Oxacillin injection

Generic name: Oxacillin

Drug class: Penicillinase-resistant penicillin antibiotic

Dosage form: Injection (intramuscular or intravenous)

Route of administration: Intramuscular (IM) or intravenous (IV)

Dose:

• Adults: 250 to 500 mg IM or IV every 4 to 6 hours for mild to moderate infections; 1 g IM or IV every 4 to 6 hours for severe infections.
• Infants and children weighing less than 40 kg (88 lbs): 50 mg/kg/day IM or IV in equally divided doses every 6 hours for mild to moderate infections; 100 mg/kg/day IM or IV in equally divided doses every 4 to 6 hours for severe infections.
• Neonates: 25 mg/kg/day IM or IV.

Mechanism of action: Oxacillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to cell lysis and death.

Drug usage cases:

• Treatment of infections caused by penicillin-resistant Staphylococcus aureus, including endocarditis, meningitis, pneumonia, joint infections, skin or soft tissue infections, and osteomyelitis.

Drug contraindications:

• Hypersensitivity to oxacillin, other penicillin antibiotics, or cephalosporins.
• History of severe allergic reactions (e.g., anaphylaxis) to penicillin or cephalosporin antibiotics.

Side effects:

• Allergic reactions: rash, itching, hives, swelling of the face, lips, tongue, or throat, difficulty breathing.
• Gastrointestinal: nausea, vomiting, diarrhea, abdominal pain, pseudomembranous colitis.
• Hematologic: neutropenia, agranulocytosis, bone marrow depression.
• Hepatic: elevated liver enzymes, hepatotoxicity.
• Renal: interstitial nephritis, renal tubular damage.
• Neurologic: seizures (especially with high doses or in patients with renal insufficiency).
• Injection site reactions: pain, redness, swelling, or irritation at the injection site.

Warnings:

• Use with caution in patients with a history of penicillin allergy.
• Monitor renal function during therapy, especially in patients with pre-existing renal impairment.
• Be aware of the potential for pseudomembranous colitis; discontinue therapy if severe diarrhea occurs.
• Use cautiously in elderly patients due to the risk of thrombophlebitis with intravenous administration.
• Prolonged use may lead to superinfection with non-susceptible organisms.

Use during pregnancy or breastfeeding: Oxacillin is classified as a pregnancy category B drug, indicating no evidence of risk in humans. It is excreted in breast milk; caution is advised when administering to nursing mothers. Consult a healthcare provider before use during pregnancy or lactation.