Mefoxin

Me·fox·in (m-fksn)

A trademark for the drug cefoxitin sodium.

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Mefoxin,

trademark for a cephalosporin antibiotic (cefoxitin sodium).

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cefoxitin sodium

Mefoxin

Pharmacologic class: Second-generation cephalosporin

Therapeutic class: Anti-infective

Pregnancy risk category B

Action

Interferes with bacterial cell-wall synthesis and division by binding to cell wall, causing cell to die. Active against gram-negative and gram-positive bacteria, with expanded activity against gram-negative bacteria. Exhibits minimal immunosuppressant activity.

Availability

Powder for injection: 1 g, 2 g

Premixed containers: 1 g/50 ml in dextrose 5% in water (D₅W), 2 g/50 ml in D₅W

⊘Indications and dosages

➣ Respiratory tract infections, skin infections, bone and joint infections, urinary tract infections, gynecologic infections, septicemia

Adults: For most infections, 1 g I.M. or I.V. q 6 to 8 hours. For severe infections, 1 g I.M. or I.V. q 4 hours or 2 g I.M. or I.V. q 6 to 8 hours. For life-threatening infections, 2 g I.V. q 4 hours or 3 g I.V. q 6 hours.

Children ages 3 months and older: For most infections, 13.3 to 26.7 mg/kg I.M. or I.V. q 4 hours or 20 to 40 mg/kg q 6 hours.

➣ Preoperative prophylaxis

Adults: 1 to 2 g I.V. within 60 minutes of incision, then q 6 hours for up to 24 hours

Dosage adjustment

• Renal failure

Contraindications

• Hypersensitivity to cephalosporins or penicillins

Precautions

Use cautiously in:
• renal impairment, hepatic disease, or biliary obstruction
• history of GI disease
• elderly patients
• children.

Administration

• Obtain specimens for culture and sensitivity testing as necessary before starting therapy.
• Reconstitute 1-g dose with 10 ml of sterile water; reconstitute 2-g dose with 10 to 20 ml.
• For direct I.V. injection, give 10 ml of sterile water with each gram of cefoxitin over 3 to 5 minutes. Inject into large vein and rotate sites, or give through existing I.V. tubing.
• For intermittent or continuous I.V. infusion, add reconstituted drug to compatible solution, such as D₅W, normal saline solution, or D₅W and normal saline solution.
• For I.M. injection, reconstitute each gram with 2 ml of sterile water or 2 ml of 0.5% lidocaine hydrochloride (without epinephrine).
• Inject I.M. deep into large muscle mass; divide 2-g dose in half and inject into separate large muscle masses.
• Know that dry powder and solution may darken, but this does not alter drug efficacy.

Route	Onset	Peak	Duration
I.V.	Rapid	End of infusion	4-8 hr
I.M.	Rapid	30 min	4-8 hr

Adverse reactions

CNS: headache, lethargy, paresthesia, syncope, seizures

CV: hypotension, palpitations, chest pain, vasodilation, thrombophlebitis

EENT: hearing loss

GI: nausea, vomiting, diarrhea, abdominal cramps, oral candidiasis, pseudomembranous colitis

GU: vaginal candidiasis, nephrotoxicity

Hematologic: lymphocytosis, eosinophilia, bleeding tendency, hemolytic anemia, hypoprothrombinemia, neutropenia, thrombocytopenia, agranulocytosis, bone marrow depression

Hepatic: hepatic failure, hepatomegaly

Musculoskeletal: arthralgia

Respiratory: dyspnea

Skin: urticaria, maculopapular or erythematous rash

Other: chills, fever, superinfection, pain at I.M. site, anaphylaxis, serum sickness

Interactions

Drug-drug. Aminoglycosides, loop diuretics: increased risk of nephrotoxicity

Probenecid: decreased excretion and increased blood level of cefoxitin

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, eosinophils, gamma-glutamyltransferase, lactate dehydrogenase: increased levels

Coombs' test, urinary 17-ketosteroids, nonenzyme-based urine glucose tests (such as Clinitest): false-positive results

Hemoglobin, platelets, white blood cells: decreased values

Patient monitoring

• Assess CBC and kidney and liver function test results.
• Monitor fluid intake and output. Report significant decrease in output.
• Monitor for signs and symptoms of superinfection and other serious adverse reactions.
• Be aware that cross-sensitivity to penicillins may occur.

Patient teaching

• Instruct patient to report reduced urinary output, persistent diarrhea, bruising, and bleeding.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.