Drug reference

Oxacillin

Penicillin · Antibiotic

PenicillinAntibiotic

CDSCO approvedSchedule H1

EXCRETION

—

not curated

INTERACTIONS

1 major

SEVERE in our sources

PREGNANCY

. Single dose of oral metronidazole (additional intraoperative or postoperative doses may be given for

FDA category + note

Top interactions

MethotrexateSevereDatabaseDDInter

Mechanism

Oxacillin is a semisynthetic isoxazolyl penicillin that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs) and blocking peptidoglycan transpeptidation. The isoxazolyl side chain sterically shields the beta-lactam ring from hydrolysis by staphylococcal penicillinases, providing activity against penicillinase-producing Staphylococcus aureus. It has a narrow antibacterial spectrum confined primarily to gram-positive cocci and is the parenteral penicillinase-resistant penicillin of choice in North America.

Indications

Skin and soft-tissue infectionsSerious infections due to MSSAEndocarditis (methicillin-susceptible S. aureus)Serious infections sensitive to methicillin but resistant to penicillin

Dosing

Adult: is ~0.5 unit/mL (0.3 μg/mL) after an oral dose of 400,000 units. (~250 mg) in an adult. Ingestion of food may interfere with enteric. 500 mg is nearly 3 μg/mL. Once absorbed, penicillin V is distributed in the body and excreted by the kidney in a manner similar to