Cefmetazole Sodium

(USAN, rINNM)
Synonyms: Cefmetazol sódico; Cefmétazole Sodique; Cefmetazolnatrium; Cefmetazolum Natricum; CS-1170; Kefmetatsolinatrium; Natrii Cefmetazolum; SKF-83088; U-72791A.
Cyrillic synonym: Натрий Цефметазол.

💊 Chemical information

Chemical formula: C15H16N7NaO5S3 = 493.5.
CAS — 56796-39-5.
ATC — J01DC09.
ATC Vet — QJ01DC09.

Pharmacopoeias.

In Jpn and US.

USP 31

(Cefmetazole Sodium). A white solid. Very soluble in water and in methyl alcohol; soluble in acetone; practically insoluble in chloroform. pH of a 10% solution in water is between 4.2 and 6.2. Store in airtight containers.

💊 Adverse Effects and Precautions

As for Cefalotin Sodium. Cefmetazole contains an N-methylthiotetrazole side-chain and has the potential to cause hypoprothrombinaemia and bleeding.

Effects on the blood.

References.
1. Breen GA, St Peter WL. Hypoprothrombinemia associated with cefmetazole. Ann Pharmacother 1997; 31: 180–4.

Sodium content.

Each g of cefmetazole sodium contains about 2 mmol of sodium.

💊 Interactions

As for Cefamandole.

💊 Antimicrobial Action

Cefmetazole is a cephamycin antibacterial with a similar spectrum of antibacterial activity to that of cefoxitin, including the anaerobe Bacteroides fragilis.
1. Cornick NA, et al. Activity of cefmetazole against anaerobic bacteria. Antimicrob Agents Chemother 1987; 31: 2010–12.

💊 Pharmacokinetics

After cefmetazole sodium 2 g intravenously every 6 hours, peak and trough plasma concentrations of 138 and 6 micrograms/mL have been achieved. Cefmetazole is 65 to 85% bound to plasma proteins, depending on the plasma concentration. A plasma halflife of about 1.1 to 1.5 hours has been reported; it is prolonged in patients with renal impairment. Small amounts have been detected in breast milk. Relatively high concentrations have been achieved in bile. The majority of a dose is excreted unchanged in the urine resulting in high concentrations; up to 85% of a dose has been recovered within 12 hours. Cefmetazole is partly excreted by renal tubular secretion and probenecid prolongs elimination. Cefmetazole is removed to some extent by haemodialysis.

💊 Uses and Administration

Cefmetazole is a cephamycin antibacterial generally classified with the second-generation cephalosporins and used similarly to cefoxitin in the treatment and prophylaxis of anaerobic and mixed bacterial infections, especially intra-abdominal and pelvic infections. It may also be used in the treatment of gonorrhoea. For details of these infections and their treatment, see under Choice of Antibacterial. Cefmetazole is given intravenously as the sodium salt by infusion over 10 to 60 minutes or by slow injection over 3 to 5 minutes. Cefmetazole sodium is also used intramuscularly in some countries. Doses are expressed in terms of the equivalent amount of cefmetazole; 1.05 g of cefmetazole sodium is equivalent to about 1 g of cefmetazole. The usual dose is 0.5 to 1 g intramuscularly or intravenously every 12 hours. For severe infections the dose may be increased to 3 to 4 g daily, given in divided doses every 6 to 8 hours. For details of reduced dosage of cefmetazole in patients with renal impairment, see below.
1. Finch R, et al. eds. Cefmetazole: a clinical appraisal. J Antimicrob Chemother 1989; 23 (suppl D): 1–142.

Administration in renal impairment.

Doses of cefmetazole should be reduced in patients with renal impairment. It has been suggested that the interval between doses should be 12, 16, or 24 hours in patients with mild, moderate, or severe renal impairment, respectively; patients with virtually no renal function might be given cefmetazole every 48 hours, after haemodialysis.

💊 Preparations

USP 31: Cefmetazole for Injection; Cefmetazole Injection.

Proprietary Preparations

Hong Kong: Cefmetazon†; Ital.: Metacaf†; Metafar; Metasal†; Metax; Metazol†; Jpn: Cefmetazon†; USA: Zefazone†.
Published January 02, 2019.