Aztreonam is indicated for the treatment of infections caused by susceptible Gram-negative organisms, including:

• Urinary Tract Infections (UTIs): Both complicated and uncomplicated cases, including pyelonephritis and cystitis (initial or recurrent), caused by organisms such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella oxytoca, Citrobacter species, and Serratia marcescens.
• Lower Respiratory Tract Infections: Including pneumonia and bronchitis caused by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Haemophilus influenzae, Proteus mirabilis, Enterobacter species, and Serratia marcescens.
• Septicemia: Caused by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Serratia marcescens, and Enterobacter species.
• Skin and Soft Tissue Infections: Including infections associated with surgical wounds, ulcers, and burns caused by Escherichia coli, Proteus mirabilis, Serratia marcescens, Enterobacter species, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Citrobacter species.
• Intra-abdominal Infections: Including peritonitis caused by Escherichia coli, Klebsiella species (including K. pneumoniae), Enterobacter species (including E. cloacae), Pseudomonas aeruginosa, Citrobacter species (including C. freundii), and Serratia species (including S. marcescens).
• Gynecological Infections: Including endometritis and pelvic cellulitis caused by Escherichia coli, Klebsiella pneumoniae, Enterobacter species (including E. cloacae), and Proteus mirabilis.
• Adjunct to Surgery: Used alongside surgical procedures for the management of infections caused by susceptible organisms.

Aztreonam is a synthetic monobactam antibiotic with bactericidal activity. It exerts its effect by inhibiting bacterial cell wall synthesis through interference with peptidoglycan cross-linking. This action occurs due to its strong affinity for penicillin-binding protein 3 (PBP3). By binding to PBP3, aztreonam disrupts the final stage of bacterial cell wall formation, leading to cell lysis. This process is facilitated by bacterial autolytic enzymes such as autolysins. Aztreonam may also interfere with inhibitors of these autolytic enzymes.

Adults: The recommended dosage for Urinary tract infections , Moderately severe systemic infections and Severe systemic or life-threatening infections is 500 mg or 1 g , 1 g or 2 g, 2 g every 8 or 12, 8 or 12 and 6 or 8 hourly respectively.

Children: The recommended dosage for Mild to moderate infections (Over 1 week) and Moderate to severe infections (2 years or older) is 30 mg/kg and 50 mg/kg every 6 and 6 or 8 hourly respectively. Maximum recommended dose for adult is 8 g per day. Maximum recommended dose for pediatric patient is 120 mg/kg/day.

Pediatric use: Dosage information is not yet available for new born less than one week.

Administration
Intramuscular administration: The dose should be given by deep injection into a large muscle mass. Aztreonam is well tolerated and should not be administered with any local anesthetic agent. For each gram of Aztreonam add at least 3 ml water for injection BP and shake well.
Intravenous administration: A bolus injection may be used to initiate therapy. The dose should be slowly injected directly into a vein, or the tubing of a suitable administration set, over a period of 3 to 5 minutes.

For infusion: Each gram of Aztreonam should be initially constituted with at least 3 ml of water for injection BP. The resulting solution should be diluted with an appropriate infusion solution to a final concentration not exceeding 2% w/v (at least 50 ml solution per gram Aztreonam). The Aztreonam infusion should be administered over a 20-60 minute period. A number of intravenous solutions may be used as diluents for the administration of Aztreonam by intravenous infusion.These include sodium chloride injection, dextrose and mixed injections of sodium chloride and dextrose, Ringers and lactated Ringers injection,water for injection etc.

Co-administration of aztreonam with probenecid or furosemide may cause slight increases in serum aztreonam levels; however, these changes are not considered clinically significant.

Aztreonam is contraindicated in patients with known hypersensitivity to aztreonam or any component of the formulation.

Local reactions such as phlebitis or thrombophlebitis may occur following intravenous administration, while pain, swelling, or discomfort may occur at the intramuscular injection site. Systemic adverse effects may include diarrhea, nausea, vomiting, and skin rash. Less commonly, serious reactions such as anaphylaxis, angioedema, bronchospasm, and various blood disorders (including pancytopenia, neutropenia, thrombocytopenia, anemia, eosinophilia, leukocytosis, and thrombocytosis) may occur. Other possible effects include abdominal cramps, dermatitis, urticaria, itching, hypotension, flushing, seizures, weakness, headache, fever, and malaise.

Aztreonam is classified as Pregnancy Category B. It crosses the placenta and enters fetal circulation. Therefore, it should be used during pregnancy only if the expected benefit outweighs the potential risk. Aztreonam is excreted into breast milk in very small amounts (less than 1% of maternal serum levels). Temporary discontinuation of breastfeeding is recommended during treatment.

In patients with impaired liver or kidney function, appropriate monitoring should be carried out during therapy.

Other beta-lactam antibiotics.

Store in a cool and dry place, protected from light and moisture. Keep all medicines out of reach of children.