Cefmetazole

Cefmetazole is a broad‑spectrum cephalosporin antibiotic of the cephamycin subclass, a type of beta‑lactam antimicrobial. Like other beta‑lactams, it inhibits bacterial cell wall synthesis by binding to penicillin‑binding proteins, resulting in bacterial death.

Spectrum and activity: Cefmetazole has activity against many Gram‑positive cocci and Gram‑negative rods, and notable activity against anaerobic bacteria such as Bacteroides fragilis. Its activity against Enterobacterales is variable, and coverage of Pseudomonas aeruginosa is limited.

Pharmacokinetics and administration: For systemic infections, cefmetazole is administered by intravenous or intramuscular injection. It is primarily excreted by the kidneys, so dose adjustment is needed in renal impairment. The drug distributes moderately throughout body tissues.

Clinical use: Cefmetazole is used for mixed infections where anaerobic coverage is beneficial, including intra‑abdominal infections, certain gynecologic infections, biliary tract infections, pelvic inflammatory disease, and some skin and soft tissue infections caused by susceptible organisms. It is also employed in some settings for surgical prophylaxis.

Adverse effects and safety: Common adverse events include diarrhea, nausea, rash, and hypersensitivity reactions. As with other antibiotics, prolonged use can lead to superinfection, including Clostridioides difficile–associated diarrhea.

Contraindications: Cefmetazole should not be used in individuals with a known hypersensitivity to cephalosporins or other beta‑lactam antibiotics.

Notes: Like other cephamycins, cefmetazole generally shows less activity against non‑fermenting Gram‑negatives such as Pseudomonas aeruginosa compared with some third‑generation cephalosporins. Regional availability and guidelines influence its use.