AZTREONAM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AZTREONAM (AZTREONAM).
Aztreonam is a monobactam antibacterial that inhibits bacterial cell wall synthesis by binding to penicillin-binding protein 3 (PBP3) of Gram-negative bacteria, leading to cell death.
| Metabolism | Aztreonam is primarily metabolized by hydrolysis of the beta-lactam ring to inactive metabolites. It is not metabolized by CYP450 enzymes. |
| Excretion | Renal: 60-70% unchanged via glomerular filtration and tubular secretion; nonrenal: 30-40% (hepatic metabolism to inactive metabolites and biliary excretion, with <1% fecal elimination). |
| Half-life | Terminal elimination half-life is 1.5-2 hours in adults with normal renal function; prolonged to 6-9 hours in end-stage renal disease (CrCl <10 mL/min). |
| Protein binding | Approximately 56% bound to serum albumin. |
| Volume of Distribution | 0.1-0.3 L/kg, indicating distribution primarily into extracellular fluid. |
| Bioavailability | Intramuscular: nearly 100% (bioequivalent to intravenous); oral: not applicable (not orally bioavailable). |
| Onset of Action | Intravenous: immediate; intramuscular: within 30-60 minutes. |
| Duration of Action | 6-8 hours; dosing interval adjusted in renal impairment. |
1-2 g IV or IM every 6-8 hours; maximum 8 g/day.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 30-90 mL/min: same dose, interval every 12 hours; CrCl 10-30 mL/min: 500 mg-1 g initial, then 250-500 mg every 12 hours; CrCl <10 mL/min: 500 mg-1 g initial, then 250 mg every 12 hours; hemodialysis: 500 mg-1 g initial, then 250 mg every 12 hours, give after dialysis. |
| Liver impairment | No adjustment required for Child-Pugh A or B; Child-Pugh C: caution, monitor for adverse effects, specific dose modifications not established. |
| Pediatric use | Neonates: 30 mg/kg IV every 12 hours; Infants/children: 30-50 mg/kg IV every 6-8 hours, maximum 120 mg/kg/day; Cystic fibrosis: 50 mg/kg IV every 6 hours, maximum 200 mg/kg/day. |
| Geriatric use | No specific dose adjustment based on age alone; adjust based on renal function; monitor renal status. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AZTREONAM (AZTREONAM).
| Breastfeeding | Aztreonam is excreted into breast milk in low concentrations (M/P ratio ~0.01-0.04). Considered compatible with breastfeeding; use with caution in nursing mothers. |
| Teratogenic Risk | Pregnancy Category B. No evidence of teratogenicity in animal studies; no adequate controlled studies in pregnant women. Risk cannot be ruled out; use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA boxed warning exists for aztreonam.
| Serious Effects |
["Hypersensitivity to aztreonam or any component of the formulation"]
| Precautions | ["Hypersensitivity reactions, including anaphylaxis, may occur; cross-allergenicity with other beta-lactams is low but possible.","Clostridioides difficile-associated diarrhea (CDAD) can occur with use.","Renal impairment requires dose adjustment.","Superinfection with Gram-positive or anaerobic organisms may occur due to lack of activity against these pathogens.","Seizures have been reported rarely, especially in patients with renal impairment."] |
| Food/Dietary | No clinically significant food interactions. Aztreonam absorption is not affected by food. No specific dietary restrictions are required. However, patients should maintain good hydration. There is no need to avoid any particular foods. |
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| Monitor maternal renal function, hepatic function, and complete blood counts periodically. No specific fetal monitoring required beyond routine prenatal care. |
| Fertility Effects | No known adverse effects on fertility in animal studies; no human data available. |
| Clinical Pearls | Aztreonam is a monobactam antibiotic with activity against aerobic gram-negative bacilli, including Pseudomonas aeruginosa. It lacks activity against gram-positive and anaerobic organisms. It is safe in penicillin-allergic patients as cross-reactivity is minimal, but caution is advised in patients with severe immediate-type hypersensitivity. Dose adjustment is required in renal impairment; for CrCl 10-30 mL/min, extend dosing interval to every 12 hours. Monitor for Clostridioides difficile-associated diarrhea and potential for neurotoxicity (especially with high doses or in renal failure). |
| Patient Advice | Take this medication exactly as prescribed by your doctor. Do not skip doses or stop early, even if you feel better. · If you are receiving it by injection, it should be given by a healthcare professional. Do not attempt to inject yourself. · Report any signs of an allergic reaction, such as rash, itching, swelling, or trouble breathing, especially if you are allergic to penicillin; however, cross-reactions are rare. · Notify your doctor if you develop severe diarrhea, abdominal pain, or bloody stools, which could indicate C. difficile infection. · Maintain adequate hydration to prevent kidney strain. Inform your doctor if you have a history of kidney disease or are taking other medications that may affect the kidneys. · Avoid alcohol while on aztreonam as it may increase the risk of side effects such as nausea and vomiting. |