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# Aztreonam-avibactam (Avycaz) ## Overview Aztreonam-avibactam is a combination antibiotic containing aztreonam, a monobactam beta-lactamase resistant antibiotic, and avibactam, a beta-lactamase inhibitor. It is active against aerobic Gram-negative bacteria, including many multidrug-resistant organisms like *Pseudomonas aeruginosa*, Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs), carbapenemases (e.g., KPC, OXA-48-like, VIM, IMP, NDM), and *Actinobacter baumannii*. ## Primary Indications * Complicated intra-abdominal infection (cIAI) in combination with metronidazole. * Complicated urinary tract infection (cUTI), including pyelonephritis. * Complicated intra-abdominal infection (cIAI). * Nosocomial pneumonia, including ventilator-associated pneumonia (VAI). * Treatment of infections caused by aerobic Gram-negative bacteria with limited or no alternative treatment options. ## Adult Dosing **For cIAI, cUTI, and hospital-acquired/ventilator-associated pneumonia:** * **Dose:** 2.5 grams (2g aztreonam/0.5g avibactam) administered intravenously over 3 hours every 8 hours. * **Duration:** Typically 7 to 14 days. Duration depends on severity, pathogen, and clinical response. * **Combination:** For cIAI, reconstitute and administer with metronidazole. ## Pediatric Dosing Dosing is based on weight and indication: * **cUTI:** 50 mg/kg (aztreonam component) with 12.5 mg/kg (avibactam component) IV every 8 hours. Maximum dose of 2 grams aztreonam/500 mg avibactam per dose. * **cIAI and HA/VAP:** 75 mg/kg (aztreonam component) with 18.75 mg/kg (avibactam component) IV every 8 hours. Maximum dose of 2 grams aztreonam/500 mg avibactam per dose. * **Age/Weight Restrictions:** Dosing has been established in pediatric patients from 3 months to <18 years old. See specific product labelling for precise weight criteria for each indication. ## Dose Adjustments * **Renal Impairment:** * CrCl ≥ 50 mL/min: No adjustment needed. * CrCl 30 to < 50 mL/min: 1.25 grams IV every 8 hours. * CrCl 10 to < 30 mL/min: 1 gram IV every 12 hours. * CrCl < 10 mL/min: 0.75 grams IV every 12 hours. * **Hemodialysis:** 1.25 grams IV every 12 hours, with supplemental dose of 0.75 grams after each dialysis session. * **Hepatic Impairment:** No dose adjustment necessary. * **Pediatric Renal Impairment:** Dosing adjustments are complex and depend on renal function parameters, and should be guided by clinical assessment and local protocols. ## Contraindications * Hypersensitivity to aztreonam, avibactam, or any component of the formulation. * Known severe immediate hypersensitivity reaction to penicillins, cephalosporins, or other