nafcillin (Rx)

1-10%

Hypersensitivity

Neutropenia

Interstitial nephritis

Possible hypokalemia

<1%

Neurotoxicity (high doses)

Pseudomembranous colitis

Phlebitis (oxacillin preferred in peds)

Contraindications

A history of a hypersensitivity (anaphylactic) reaction to any penicillin

Solutions containing dextrose in patients with known allergy to corn or corn products

Cautions

Evaluate renal, hepatic, hematologic systems periodically during prolonged treatment

Serious and occasionally fatal hypersensitivity (anaphylactic) reactions reported; reactions are more likely to occur in individuals with history of penicillin hypersensitivity and/or a history of sensitivity to multiple allergens; inquire about previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens before initiating therapy; if allergic reaction occurs, discontinue treatment and institute appropriate therapy

If clostridium difficile associated diarrhea (CDAD) suspected or confirmed, may need to discontinue ongoing antibiotic use not directed against C. difficile; appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated

The use of antibiotics may result in overgrowth of nonsusceptible organisms; if new infections due to bacteria or fungi occur, discontinue drug and take appropriate measures

To optimize therapy, determine causative organisms and susceptibility; > 10 d treatment to eliminate infection and prevent sequelae (eg, endocarditis, rheumatic fever); take cultures after treatment to confirm that infection is eradicated

Elevation of liver transaminases and/or cholestasis may occur, specifically with administration of high doses

Urinalysis, serum blood urea nitrogen, and creatinine determinations should be performed at baseline and periodically during therapy; serum bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, and gamma glutamyl transferase should be obtained at baseline and periodically during therapy, especially when using high nafcillin doses; in patients with worsening hepatic

Renal tubular damage and interstitial nephritis associated with administration of nafcillin; manifestations of nephrotoxicity are hematuria, proteinuria, and acute kidney injury, and may be associated with rash, fever, and eosinophilia; majority of cases resolve upon discontinuation of nafcillin; some patients, may require dialysis treatment and may develop permanent renal damage

Pregnancy Category: B

Lactation: Excreted into breast milk; use caution

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Inhibit synthesis of bacterial cell wall synthesis, which results in bactericidal activity

Pharmacokinetics

Half-Life: 0.5-1.5 hr (adults); 0.75-1.9 hr (children)

Peak Plasma Time: 0.5-1 hr

Protein binding: 90%

Absorption: Poorly absorbed orally

Distribution: In fluid, bone, bile, crosses placenta

Vd: 0.5-1.5 L/kg

Metabolism: Liver

Excretion: Liver (primarily), renal (10-30%)

Enzymes induced: Hepatic CYP3A4

IV Incompatibilities

Additive: aminophylline(?), ascorbic acid, aztreonam, bleomycin, cytarabine, gentamicin, hydrocortisone sodium succinate, methylprednisolone sodium succinate, promazine, vit B/C(?)

Y-site: diltiazem(?), droperidol, insulin (regular), labetalol, meperidine(?), midazolam, nalbuphine, pentazocine, vancomycin(?), verapamil

IV Compatibilities

Solution: compatible w/ most common solvents

Additive (partial list): dexamethasone sodium phosphate, diphenhydramine, heparin, lidocaine, KCl, prochlorperazine, Na bicarb

Syringe: cimetidine, heparin

Y-site (partial list): acyclovir, atropine, diazepam, fentanyl, fluconazole, heparin, MgSO4, morphine, propofol, zidovudine

IV/IM Preparation

IM/IV: reconstitute 1-2 g of drug w/ 3.4- 6.8 mL SWI/BWI/NS to 250 mg/mL

IV inj: further dilute w/ 15-30 mL SWI/NS

IV infusion: further dilute w/ IV solution according to Mfr's directions

Bulk Packages:

• Reconstitute 10 g of drug w/ 93 mL SWI/NS to 100 mg/mL
• THEN further dilute before administration
• Not for direct IV injection

IV/IM Administration

IM: deep into large muscle

IV inj: slowly over 5-10 min

IV infusion: over at least 30-60 min