Inhalation/Respiratory Pseudomonal lung infections in cystic fibrosis
Adult: As aztreonam lysine: 75 mg tid over 2-3 min, w/ at least 4 hr apart for 28 days. Should be taken w/ bronchodilators prior to each dose: 15 min to 4 hr (short-acting) and 30 min to 12 hr (long-acting) before inhaled aztreonam. May be taken in repeated 28 days cycle on therapy followed by 28 days off therapy. Child: >6 yr Same as adult dose.
Intramuscular Cystitis, Gonorrhoea
Adult: 1 g as a single dose.
Intravenous Cystic fibrosis
Adult: 2 g 6-8 hrly by slow inj over 3-5 min or infusion over 20-60 min.
Parenteral Bone and joint infections, Intra-abdominal infections, Lower respiratory tract infections, Meningitis, Pelvic infections, Septicaemia, Skin and soft tissue infections
Adult: 1-8 g daily in divided doses 6-12 hrly by deep IM inj, slow IV inj over 3-5 min or IV infusion over 20-60 min. Child: 1 wk to <2 yr 30 mg/kg 6 or 8 hrly; 2-12 yr 30 mg/kg 6 or 8 hrly, may increase to 50 mg/kg to max 8 g daily. Doses may be given by deep IM inj, slow IV inj over 3-5 min or IV infusion over 20-60 min.
Parenteral Urinary tract infections
Adult: 0.5 g or 1 g 8 or 12 hrly by deep IM inj, slow IV inj over 3-5 min or IV infusion over 20-60 min.
Renal Impairment
IM/IV:
Haemodialysis: A supplementary dose of 1/8 of the initial dose after each dialysis.
CrCl (mL/min)
Dosage
<10
One-quarter of the initial dose.
10-30
Half of the initial dose.
Reconstitution
Inhalation: Reconstitute w/ the solvent provided, gently swirl. IM: Reconstitute vial w/ at least 3 mL of sterile water for inj, sterile bacteriostatic water for inj, normal saline, or bacteriostatic NaCl per g of aztreonam; immediately shake vigorously. IV: Bolus inj: Reconstitute vial w/ 6-10 mL of sterile water for inj. Infusion: Reconstitute vial w/ at least 3 mL of sterile water for inj per g of aztreonam; immediately shake vigorously. Then further dilute in an appropriate soln for infusion to a final concentration of ≤2%.
Monitor for signs of anaphylaxis during 1st dose; periodic LFT. Consider measuring FEV1 prior to initiation of inhalation therapy.
Drug Interactions
Concurrent use w/ oral anticoagulants may increase prothrombin time.
Lab Interference
May interfere w/ urine glucose tests using cupric sulfate (e.g. Benedict’s soln, Clinitest®). Positive Coombs’ test.
Action
Description: Mechanism of Action: Aztreonam inhibits bacterial cell wall synthesis due to its high affinity for penicillin-binding protein 3 (PBP-3) of gm-ve bacteria. It is highly resistant to hydrolysis by many narrow-spectrum β-lactamases. It is also active against most Enterobacteriaceae (including E. coli, Citrobacter, Enterobacter, Klebsiella, Proteus, Providencia, Salmonella, Serratia, Shigella, Yersinia spp. and Morganella morganii). Pharmacokinetics: Absorption: Rapidly and completely absorbed (IM); low systemic absorption (inhalation). Time to peak plasma concentration: W/in 1 hr (IM and IV bolus); 1.5 hr (IV infusion). Distribution: Widely distributed into body tissues and fluids including bile; CSF (especially in the presence of meningitis); crosses the placenta and enters foetal circulation; enters breast milk (small amounts). Plasma protein binding: Approx 56%. Metabolism: Not extensively metabolised; SQ-26992 (inactive principal metabolite) is formed by opening of the β-lactam ring. Excretion: Mainly via urine by renal tubular secretion and glomerular filtration (approx 60-70% as unchanged drug and metabolites for IM/IV; approx 10% for inhalation); faeces (approx 13-15% as unchanged drug and metabolites for IM/IV). Plasma half-life: Approx 1.7 hr (IM/IV); approx 2.1 hr (inhalation).
Chemical Structure
Aztreonam Source: National Center for Biotechnology Information. PubChem Database. Aztreonam, CID=54117, https://pubchem.ncbi.nlm.nih.gov/compound/Aztreonam (accessed on Jan. 21, 2020)
Storage
Powd for inhalation: Store between 2-8°C. Powd for inj: Store below 25°C. Reconstituted inj soln: Store between 2-8°C for not more than 24 hr.
Anon. Aztreonam. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 25/06/2015.Azactam. U.S. FDA. https://www.fda.gov/. Accessed 25/06/2015.Aztreonam Injection, Powder, Lyophilized, for Solution (Fresenius Kabi USA, LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 25/06/2015.Buckingham R (ed). Aztreonam. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 25/06/2015.McEvoy GK, Snow EK, Miller J et al (eds). Aztreonam. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 25/06/2015.
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