CEPHAZOLIN

What it is

Cephazolin is cefazolin sodium supplied as a powder for injection. It is supplied in vials containing cefazolin sodium equivalent to 500 mg, 1 g and 2 g cefazolin. The powder reconstitutes with Sterile Water for Injection to give a colourless solution. Cephazolin is a semisynthetic cephalosporin for parenteral administration.

Approved indications —

Respiratory tract infections due to Streptococcus pneumoniae, Klebsiella species, Haemophilus influenzae, Staphylococcus aureus (penicillin sensitive and penicillin resistant) and group A beta-haemolytic streptococci. — Genitourinary tract infections due to Escherichia coli, Proteus mirabilis, Klebsiella species and some strains of Enterobacter and Enterococci. — Skin and skin structure infections due to Staphylococcus aureus (penicillin sensitive and penicillin resistant), group A beta-haemolytic streptococci and other strains of Streptococci. — Bone and joint infections due to Staphylococcus aureus. — Septicaemia due to Streptococcus pneumoniae, Staphylococcus aureus (penicillin sensitive and penicillin resistant), Proteus mirabilis, Escherichia coli and Klebsiella species. — Endocarditis due to Staphylococcus aureus (penicillin sensitive and penicillin resistant) and group A beta-haemolytic streptococci.

Dosing overview

The usual dosage for mild Gram positive infections in adults is cefazolin 250 to 500 mg every eight hours. For mild to moderate infections of the respiratory tract caused by Streptococcus pneumoniae, or mild to moderate infections of the genitourinary tract caused by susceptible organisms, a dosage of 500 mg to 1 g every 12 hours may be used. In moderate or severe infections, the usual adult dosage is cefazolin 500 mg to 1 g every six to eight hours. Cephazolin has been administered in dosages of 6 g per day in serious infections such as endocarditis. For children, a total daily dosage of 25 to 50 mg/kg bodyweight, divided into three or four equal doses, is effective for most mild to moderately severe infections. Total daily dosage may be increased to 100 mg/kg bodyweight for severe infections. Cephazolin may be administered intramuscularly or intravenously after reconstitution.

Key safety warnings

Before cefazolin therapy is instituted, careful inquiry should be made concerning previous hypersensitivity reactions to cephalosporins and penicillin. Cephalosporin derivatives should be given cautiously in penicillin sensitive patients. Serious acute hypersensitivity reactions may require adrenaline and other emergency measures. There is some clinical and laboratory evidence of partial cross allergenicity of the penicillins and the cephalosporins. Patients have been reported to have had severe reactions (including anaphylaxis) to both drugs. Antibiotic associated pseudomembranous colitis has been reported with many antibiotics including cefazolin. A toxin produced by Clostridium difficile appears to be the primary cause. The severity of the colitis may range from mild to life threatening. It is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use (this may occur up to several weeks after cessation of antibiotic therapy). Severe cutaneous adverse reactions (SCAR), such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalised exanthematous pustulosis (AGEP) have been reported in patients taking beta-lactam antibiotics. When SCAR is suspected, Cephazolin should be discontinued immediately and an alternative treatment should be considered. There have been reports of neurotoxicity associated with cephalosporin treatment. Symptoms of neurotoxicity include seizures and/or myoclonus. Risk factors for developing neurotoxicity with cephalosporin treatment include being elderly, renal impairment, central nervous system disorders and intravenous administration.

Contraindications

Known allergy to the cephalosporin group of antibiotics or previous experience of a major allergy to penicillin is a contraindication to use. Lidocaine (lignocaine) should not be used as a diluent for intramuscular injection in patients who are hypersensitive to lidocaine (lignocaine).

PBS listing

Cephazolin is listed on the PBS as a powder for injection 2 g (as sodium) with 3 PBS items, restriction type restricted, and an ex-manufacturer price of A$30.90.

Regulatory history

Cephazolin AFT 500 mg and 1 g received initial ARTG approval on 6 March 2012, and the 2 g strength received approval on 7 February 2022.