Nafcillin
Nafcillin is a penicillinase-resistant penicillin antibiotic used primarily to treat infections caused by Staphylococcus aureus bacteria. It is particularly effective against staphylococcal infections that would otherwise be resistant to other penicillin antibiotics.
Nafcillin is a penicillin-type antibiotic used to treat staph infections resistant to other penicillin antibiotics.
Key facts at a glance
- ATC
- J01CF06
- RxNorm
- 7233
- Generic
- Nafcillin
- Class
- atc-j01
- Brands
- —
- Availability
- rx
- Pregnancy
- B
- Lactation
- safe
- Routes
- oral
- Forms
- solution, injection, capsule
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Nafcillin is used to treat skin infections, soft tissue infections, bone and joint infections, and septicemia caused by susceptible strains of Staphylococcus aureus. It is especially useful when the infection is suspected to involve penicillinase-producing staphylococci.
Nafcillin works by inhibiting bacterial cell wall synthesis. Its chemical structure is resistant to inactivation by staphylococcal penicillinase enzymes, allowing it to remain effective against bacteria that have developed resistance to other penicillin antibiotics.
Nafcillin is typically administered intravenously or intramuscularly. Common side effects include rash, nausea, and liver enzyme elevations. Patients with penicillin allergies should not use this medication. It is important to complete the full course of treatment as prescribed to prevent antibiotic resistance.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy