Zerbaxa™ is a new antibiotic approved for the treatment of complicated urinary tract infections, and in combination with metronidazole, complicated intra-abdominal infections. Zerbaxa™ contains a cephalosporin, ceftolozane, and a β-lactamase inhibitor, tazobactam. Ceftolozane exhibits significant activity against Gram-negative bacilli; tazobactam extends this spectrum to include β-lactamase producing bacteria and some anaerobic species.
Ceftolozane has a similar chemical structure to ceftazidime. However, a side chain modification provides enhanced antipseudomonal activity. Pseudomonas aeruginosa is responsible for 10% of nosocomial infections. The growing incidence of multi-drug resistance in this species is associated with significant morbidity and mortality. Zerbaxa™ is able to evade many of the resistance mechanisms of P. aeruginosa including efflux pumps, reduced uptake through porin channels, and modification of penicillin-binding proteins. It is not, however, stable to carbapenemases or metallo-β-lactamases.
The most common adverse effects reported are nausea, diarrhoea, headache, and pyrexia. Zerbaxa™ does not exhibit significant activity against Clostridium difficile and the risk of C. difficile-associated diarrhoea is assumed to be the same as other β-lactam antibiotics. Excretion is predominantly renal, therefore dose reduction is recommended in patients with impaired renal function.
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- Zerbaxa™ (ceftolozane/tazobactam) Australian approved product information. Newmarket: Merck Sharp and Dohme Pty Ltd. Approved November 2015.