Clostridium difficile associated diarrhoea: Following sentence added:
Medication that inhibits intestinal peristalsis should not be given.
Overgrowth of non-susceptible organisms: Updated as below:
Therapy with Azactam may result in overgrowth of non-susceptible organisms, including gram-positive organisms and fungi. Should superinfection occur during therapy, appropriate measures should be taken.
Following sections added:
Prolongation of prothrombin time / increased activity of oral anticoagulants
Prolongation of prothrombin time has been reported rarely in patients receiving aztreonam. Additionally, numerous cases of increased activity of oral anticoagulants have been reported in patients receiving antibiotics, including beta-lactams. Severe infection or inflammation, and the age and general condition of the patient appear to be risk factors. Appropriate monitoring should be undertaken when anticoagulants are prescribed concomitantly. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation (see section 4.5 and 4.8).
Concomitant use with aminoglycosides
If an aminoglycoside is used concurrently with aztreonam, especially if high dosages of the former are used or if therapy is prolonged, renal function should be monitored because of the potential nephrotoxicity and ototoxicity of aminoglycoside antibiotics.
Paediatric population
Data on safety and effectiveness in neonates younger than one week are limited; use in this population needs to be carefully assessed.
Arginine
Aztreonam for injection contains arginine. Studies in low birth weight infants have demonstrated that arginine administered in the aztreonam formulation may result in increases in serum arginine, insulin, and indirect bilirubin. The consequences of exposure to this amino acid during treatment of neonates have not been fully ascertained.
Interference with serological testing
A positive direct or indirect Coombs test may develop during treatment with aztreonam.
4.5 Interaction with other medicinal products and other forms of interactions:
Following added
Concomitant administration of probenecid or furosemide and aztreonam cause clinically insignificant increases in the serum levels of aztreonam.
Due to the induction of beta-lactamases, certain antibiotics (eg, cefoxitin, imipenem) have been found to cause antagonism with many beta-lactams, including aztreonam, for certain gram-negative aerobes, such as Enterobacter species and Pseudomonas species.
Appropriate monitoring should be undertaken when anticoagulants are prescribed concomitantly. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation (see section 4.4 and 4.8).
4.6 Use during pregnancy and lactation
Following added:
There are no adequate and well-controlled studies in pregnant women. Studies in pregnant rats and rabbits, with daily doses up to 15 and 5 times the maximum recommended human dose respectively, revealed no evidence of embryo- or fetotoxicity or teratogenicity. Because animal reproduction studies are not always predictive of human response, aztreonam should be used during pregnancy only if clearly needed.
4.7 Effects on ability to drive and use machines
Updated as follows:
No studies on the effects on the ability to drive and use machines have been performed.
4.8 Undesirable effects
A Table of list of undesirable effects presented by system organ class, MedDRA preferred term, and frequency replaces the text.
4.9 Overdose symptoms, emergency procedures, antidotes
Following added:
If necessary, aztreonam may be cleared from the serum by hemodialysis and/or peritoneal dialysis. Aztreonam has been shown to be cleared from the serum by continuous arteriovenous hemofiltration.
