CEFMETAZOLE
(sef-met'a-zol)
Zefazone
Classifications: antiinfective; antibiotic; third-generation cephalosporin
Prototype: Cefotaxime sodium
Pregnancy Category: B

Availability

1 g, 2 g injection

Actions

Cefmetazole is a synthetic cephalosporin antibiotic. Its bactericidal action results from inhibition of cell wall synthesis.

Therapeutic Effects

Active against a wide range of gram-positive and gram-negative aerobic and anaerobic bacteria. Effectively treats abdominal and respiratory tract infections, pelvic inflammatory disease, urinary tract infections, skin and soft tissue infections and used for surgical prophylaxis, reducing or eliminating signs and symptoms of infection.

Uses

UTI infections caused by Escherichia coli, lower respiratory tract infections, namely pneumonia and bronchitis caused by Streptococcus pneumoniae, Staphylococcus aureus, E. coli, Haemophilus influenzae. In addition, it is effective against Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus agalactiae, Proteus vulgaris, and Bacteroides fragilis; preoperative prophylaxis of cesarean section, hysterectomy, cholecystectomy, and colorectal surgery.

Contraindications

Patients with known allergy to cefmetazole or to any other cephalosporin antibiotic.

Cautious Use

Allergy to penicillin, history of colitis, renal insufficiency, pregnancy (category B), lactation.

Route & Dosage

Systemic Infections
Adult: IV 1–2 g q6–12h

Surgical Prophylaxis
Adult: IV 1–2 g 30–90 min before surgery; then q8h for 2 more doses

Adjustment for Renal Impairment
Cl_cr <30 mL/min: 1–2 g q24h

Administration

Intravenous

PREPARE: Direct/Intermittent: Reconstitute with sterile water for injection, bacteriostatic water for injection, or NS. Dilute 1 g with 3.7 mL to yield 250 mg/mL or with 10 mL to yield 100 mg/mL. Dilute 2 g with 7 mL to yield 250 mg/mL or with 15 mL to yield 125 mg/mL. Solution may be further diluted to concentrations ranging from 1–20 mg/mL by adding it to D5W, NS, or RL.

ADMINISTER: Direct/Intermittent: Drug can be given direct IV over 3–5 min (for surgical prophylaxis only) or infused over 10–60 min.

INCOMPATIBILITIES Solution/additive: aminoglycosides. Y-site: aminoglycosides.

Observe IV sites for evidence of inflammatory reaction. Risk of phlebitis may be reduced by use of a small needle in a large vein.

Potency is retained for 24 h after reconstitution at room temperature, 7 d under refrigeration, and for 6 wk if frozen. Store away from heat, light, and moisture; do not refreeze.

Adverse Effects (1%)

Body as a Whole: Hypersensitivity reactions. GI: Diarrhea, loose stools, nausea, vomiting, dyspepsia, flatulence. CNS: Drug fever, headache, dizziness. Skin: Rash, pruritus. Urogenital: Vaginitis, genital pruritus.

Interactions

Drug: Probenecid decreases renal elimination of cefmetazole.

Pharmacokinetics

Elimination: Excreted unchanged in urine. Half-Life: 1.2 h.

Nursing Implications

Assessment & Drug Effects

Determine previous hypersensitivity to cephalosporins, penicillins, and history of other allergies, particularly to drugs, before therapy is initiated.
Lab tests: Perform culture and sensitivity tests before initiation of therapy and periodically during therapy. Therapy may be implemented pending test results. Monitor PT in patients with renal or hepatic disease or those receiving a long course of antibiotic therapy.
Assess for S&S of superinfections (see Appendix F) caused by overgrowth of nonsusceptible organisms, particularly with prolonged use.
Promptly report loose stools or diarrhea because of risk of pseudomembranous colitis (see Appendix F). Older adults are especially susceptible. Drug may be discontinued.

Patient & Family Education

Report onset of loose stools or diarrhea even for several weeks after drug is discontinued.
Do not ingest alcohol within 24 h of drug as this may cause a disulfiram-like reaction (see Appendix F).
Do not breast feed while taking this drug without consulting physician.

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