• Bacterial infections

Nafcillin Generic Name & Formulations

General Description

Nafcillin sodium 1g/vial, 2g/vial, 10g/vial; pwd for deep IM inj after reconstitution, IV infusion after reconstitution and dilution.

Pharmacological Class

Penicillinase-resistant penicillin.

How Supplied

Contact supplier.

Nafcillin Indications


Susceptible infections due to penicillinase-producing staphylococci.

Nafcillin Dosage and Administration


Give by deep IM gluteal inj or IV infusion over 30–60mins. IM: 500mg every 4–6hrs. IV: 500mg every 4hrs. Severe infections: 1g IM or IV every 4hrs; treat for at least 14 days, then continue for at least 48hrs after becoming afebrile, asymptomatic, or (–) cultures. Endocarditis or osteomyelitis: may need longer therapy; see full labeling. Switch to oral therapy as soon as clinically indicated.


Give by deep IM gluteal inj only. Neonates: 10mg/kg twice daily. Infants and children (<40kg): 25mg/kg twice daily.

Nafcillin Contraindications

Not Applicable

Nafcillin Boxed Warnings

Not Applicable

Nafcillin Warnings/Precautions


Cephalosporin allergy: not recommended. History of significant allergies. Asthma. Discontinue if superinfection occurs or if CDAD is suspected or confirmed. Obtain CBCs, BUN, urinalysis, creatinine, LFTs at baseline and periodically during therapy. Monitor renal, hepatic and hematopoietic function in prolonged use. Renal and hepatic impairment. Elderly (esp. IV route). Pregnancy. Nursing mothers.

Nafcillin Pharmacokinetics

See Literature

Nafcillin Interactions


May be antagonized by tetracycline; avoid. Concomitant warfarin: monitor; adjust dose as needed. May antagonize cyclosporine; monitor. Potentiated by probenecid. May cause false (+) protein urine test with sulfosalicyclic acid.

Nafcillin Adverse Reactions

Adverse Reactions

Inj site reactions, thrombophlebitis, rash, serum sickness, GI upset, neurotoxicity, renal toxicity, elevated LFTs, blood dyscrasias; hypersensitivity reactions, CDAD, pseudomembranous colitis.

Nafcillin Clinical Trials

See Literature

Nafcillin Note


Formerly known under the brand names Nallpen, Unipen.

Nafcillin Patient Counseling

See Literature