CEFOXITIN SODIUM
(se-fox'i-tin)
Mefoxin
Classifications: antiinfective; antibiotic; second-generation cephalosporin
Prototype: Cefonicid sodium
Pregnancy Category: B

Availability

1 g, 2 g injection

Actions

Semisynthetic, broad-spectrum beta-lactam antibiotic derivative of cephamycin C (produced by Streptomyces lactamdurans). Classified as second generation cephalosporin; structurally and pharmacologically related to cephalosporins and penicillins. Antimicrobial spectrum of activity resembles that of cefonicid. Considerably less active than most cephalosporins against Staphylococci. Preferentially binds to one or more of the penicillin-binding proteins (PBP) located on cell walls of susceptible organisms.

Therapeutic Effects

It shows enhanced activity against a wide variety of gram-negative organisms and is effective for mixed aerobic-anaerobic infections. Effectively treats gynecologic, bone and joint and intra-abdominal infections, gonorrhea, skin and urinary tract infections, and is used for surgical prophylaxis, reducing or eliminating infection.

Uses

Infections caused by susceptible organisms in the lower respiratory tract, urinary tract, skin and skin structures, bones and joints; also intra-abdominal endocarditis, gynecological infections, septicemia, uncomplicated gonorrhea, and perioperative prophylaxis in prosthetic arthroplasty or cardiovascular surgery. May be cephalosporin of choice for mixed aerobic-anaerobic infections (e.g., Bacteroides fragilis).

Contraindications

Hypersensitivity to cephalosporins and related antibiotics; pregnancy (category B), lactation. Safe use in children <3 mo not established.

Cautious Use

History of sensitivity to penicillin or other allergies, particularly to drugs; impaired renal function.

Route & Dosage

Moderate to Severe Infections
Adult: IV/IM 1–2 g q6–8h, up to 12 g/d
Child >3 mo : IV/IM 80–160 mg/kg/d in 4–6 divided doses (max: 12 g/d)
Neonate: IV/IM 90–100 mg/kg/d divided q8h

Surgical Prophylaxis
Adult: IV/IM 2 g 30–60 min before surgery, then 2 g q6h for 24 h
Child: IV/IM 30–40 mg/kg 30–60 min before surgery, then 2 g q6h for 24 h

Uncomplicated Gonorrhea
Adult: IV/IM 2 g given concurrently with 1 g probenecid PO

Administration

Intramuscular

Reconstitute each 1 g with 2 mL sterile water for injection or 0.5 or 1% lidocaine hydrochloride (without epinephrine), used to reduce discomfort of IM injection. After reconstitution for IM use, shake vial and allow solution to stand until it becomes clear.
Administer IM injections deep into large muscle mass such as upper outer quadrant of gluteus maximus. Aspirate before injecting drug. Rotate injection sites.

Intravenous

IV administration to neonates, infants and children: Verify correct IV concentration and rate of infusion/injection with physician.

PREPARE: Direct: Dilute each 1 g with 10 mL sterile water, D5W, or NS. Intermittent: Following reconstitution, dilute 1–2 g in 50–100 mL of D5W or NS.

ADMINISTER: Direct: Give over 3–5 min. Intermittent: Give over 15 min.

INCOMPATIBILITIES Solution/additive: aminoglycosides, ranitidine. Y-site: aminoglycosides, filgrastim, hetastarch, pentamidine, vancomycin.

Reconstituted solution may become discolored (usually light yellow to amber) if exposed to high temperatures; however, potency is not affected. Solution may be cloudy immediately after reconstitution; let stand and it will clear.

After reconstitution, solution is stable for 24 h at 25° C (77° F); 7 d when refrigerated at 4° C (39° F), or 30 wk when frozen at –20° C (–4° F).

Adverse Effects (1%)

Body as a Whole: Drug fever, eosinophilia, superinfections, local reactions: pain, tenderness, and induration (IM site), thrombophlebitis (IV site). GI: Diarrhea, pseudomembranous colitis. Skin: Rash, exfoliative dermatitis, pruritus, urticaria. Urogenital: Nephrotoxicity, interstitial nephritis.

Diagnostic Test Interference

Cefoxitin causes false-positive (black-brown or green-brown color) urine glucose reaction with copper reduction reagents such as Benedict's or Clinitest, but not with enzymatic glucose oxidase reagents (Clinistix, TesTape). With high doses, falsely elevated serum and urine creatinine (with Jaffee reaction) reported. False-positive direct Coombs' test (may interfere with cross-matching procedures and hematologic studies) has also been reported.

Interactions

Drug: Probenecid decreases renal elimination of cefoxitin.

Pharmacokinetics

Peak: 20–30 min after IM; 5 min after IV. Distribution: Poor CNS penetration even with inflamed meninges; widely distributed in body tissues including pleural, synovial, and ascitic fluid and bile; crosses placenta. Elimination: 85% excreted unchanged in urine in 6 h, small amount excreted in breast milk. Half-Life: 45–60 min.

Nursing Implications

Assessment & Drug Effects

Determine previous hypersensitivity to cephalosporins, penicillins, and other drug allergies before therapy is initiated.
Lab tests: Perform culture and sensitivity testing prior to and periodically during therapy. Periodic renal function tests.
Inspect injection sites regularly. Report evidence of inflammation and patient's complaint of pain.
Monitor I&O rates and pattern: Nephrotoxicity occurs most frequently in patients >50 y, in patients with impaired renal function, the debilitated, and in patients receiving high doses or other nephrotoxic drugs.
Be alert to S&S of superinfections (see Appendix F). This condition is most apt to occur in older adult patients, especially when drug has been used for prolonged period.
Report onset of diarrhea (may be dose related). If severe, pseudomembranous colitis (see Signs & Symptoms, Appendix F) must be ruled out. Older adult patients are especially susceptible.

Patient & Family Education

Report promptly S&S of superinfection (see Appendix F).
Report watery or bloody loose stools or severe diarrhea.
Report severe vomiting or stomach pain.
Report infusion site swelling, pain, or redness.
Do not breast feed while taking this drug.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug