Aztreonam

SCOPE: the systemic injection regimen is published because that is this page's primary route (Infectious Disease specialty, monobactam antibiotic category, and the page's own 'IV / Inhaled' ordering). The nebulised cystic fibrosis product is a different product and indication and is quoted in full below but not published in the dose field. VERBATIM (US label, Dosage in Adult Patients, Table 2 with its footnote '* Maximum recommended dose is 8 g per day'): 'Urinary tract infections 500 mg or 1 g [every] 8 or 12 [hours]; Moderately severe systemic infections 1 g or 2 g [every] 8 or 12 [hours]; Severe systemic or life-threatening infections 2 g [every] 6 or 8 [hours]'. 'Because of the serious nature of infections due to Pseudomonas aeruginosa, dosage of 2 g every six or eight hours is recommended, at least upon initiation of therapy, in systemic infections caused by this organism.' 'Doses smaller than those indicated should not be used.' 'Dosage and route of administration should be determined by susceptibility of the causative organisms, severity and site of infection, and the condition of the patient.' DURATION: 'The duration of therapy depends on the severity of infection. Generally, aztreonam for injection should be continued for at least 48 hours after the patient becomes asymptomatic or evidence of bacterial eradication has been obtained. Persistent infections may require treatment for several weeks.' ELDERLY: 'Renal status is a major determinant of dosage in the elderly... estimates of creatinine clearance should be obtained and appropriate dosage modifications made if necessary.' 'Aztreonam for injection contains no sodium.' INHALED ROUTE, NOT PUBLISHED ABOVE (UK SPC §4.2 for Cayston 75 mg powder and solvent for nebuliser solution, verbatim): 'The recommended dose for adults is 75 mg three times per 24 hours for 28 days. Doses should be taken at least 4 hours apart. Cayston may be taken in repeated cycles of 28 days on therapy followed by 28 days off Cayston therapy. The dosing in children aged 6 years and older is the same as for adults.' 'Patients should use a bronchodilator before each dose of Cayston. Short acting bronchodilators can be taken between 15 minutes and 4 hours and long acting bronchodilators can be taken between 30 minutes and 12 hours prior to each dose of Cayston. For patients taking multiple inhaled therapies, the recommended order of administration is as follows: 1. bronchodilator 2. mucolytics 3. and lastly, Cayston.' It 'should only be used with the Altera Nebuliser Handset and Altera Aerosol Head connected to an eBase Controller or an eTrack Controller'. CRITICAL SAFETY POINT (UK SPC §4.4, verbatim): 'Aztreonam for injection must not be used in the Altera or other nebulisers. Aztreonam for injection has not been formulated for inhalation, and contains arginine, a substance known to cause pulmonary inflammation.' BETA-LACTAM ALLERGY (UK SPC §4.4): 'Cross-reactivity may occur in patients with a history of allergy to beta-lactam antibiotics, such as penicillins, cephalosporins, and/or carbapenems. Animal and human data demonstrate low risk of cross-reactivity between aztreonam and beta-lactam antibiotics. Aztreonam, a monobactam, is only weakly immunogenic. Caution is advised when administering Cayston to patients if they have a history of beta-lactam allergy.'

Per-dose figure. VERBATIM (US label, Table 3, Aztreonam for Injection Dosage Guidelines for Pediatric Patients): 'Mild to moderate infections 30 mg/kg [every] 8 [hours]; Moderate to severe infections 30 mg/kg [every] 6 or 8 [hours]'. The table footnote states '* Maximum recommended dose is 120 mg/kg/day' — that ceiling is recorded here rather than in maxDose because a per-kilogram quote must not be placed in the maxDose field. AGE RANGE (US §Pediatric Use, verbatim): 'The safety and effectiveness of intravenous aztreonam for injection have been established in the age groups 9 months to 16 years... Sufficient data are not available for pediatric patients under 9 months of age or for the following treatment indications/pathogens: septicemia and skin and skin-structure infections (where the skin infection is believed or known to be due to H. influenzae type b). In pediatric patients with cystic fibrosis, higher doses of aztreonam for injection may be warranted.' INHALED ROUTE (UK SPC §4.2): 'The dosing in children aged 6 years and older is the same as for adults' (75 mg three times per 24 hours for 28 days); 'The safety and efficacy of Cayston in children younger than 6 years of age have not been established... no recommendation on posology can be given.' Pyrexia was observed at a higher incidence in paediatric patients aged 6 to 17 years than in adults (UK SPC §4.8). concentration is null — no reconstitution or infusion concentration appears in the fetched sections of either label. These paediatric figures are US labelling; verify any under-18 use against a children's formulary and local antimicrobial guidance before prescribing.