Comprehensive Guide to Aztreonam: Uses, Dosage, Side Effects, and More

What is Aztreonam?

Overview

Generic Name: Aztreonam

Brand Name: Azactam, generics

Drug Group: Monobactam antibiotic

This medication is used to:

• Treat complicated urinary tract infections (UTIs) caused by Gram-negative bacteria.
• Manage lower respiratory tract infections, including pneumonia.
• Address intra-abdominal infections and septicemia.
• Off-label uses include cystic fibrosis exacerbations or neutropenic fever under specialist guidance.

Key Characteristics

Form: Powder for injection (500 mg, 1 g, 2 g) administered IV or IM.

Mechanism: Inhibits peptidoglycan synthesis by binding to penicillin-binding proteins (PBPs), leading to bacterial cell lysis.

Approval: FDA-approved (1986 for Azactam) and EMA-approved for Gram-negative infections.

Indications and Uses of Aztreonam

Aztreonam is indicated for:

Complicated Urinary Tract Infections: Treats infections caused by Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis.

Lower Respiratory Tract Infections: Manages pneumonia or bronchitis due to Haemophilus influenzae or Pseudomonas aeruginosa.

Intra-Abdominal Infections: Addresses peritonitis or abscesses caused by Gram-negative pathogens.

Off-Label Uses: Used in cystic fibrosis patients with chronic Pseudomonas infections or as empiric therapy in neutropenic fever, guided by clinical studies.

Dosage of Aztreonam

Dosage for Adults

Uncomplicated Infections: 1 g IV or IM every 8–12 hours.

Moderate to Severe Infections: 2 g IV every 6–8 hours, up to a maximum of 8 g/day.

Urinary Tract Infections: 500 mg to 1 g IV or IM every 8–12 hours.

Dosage for Children

1 month and older: 30 mg/kg IV every 6–8 hours, up to 120 mg/kg/day (maximum 8 g/day).

Neonates: 30 mg/kg IV every 8–12 hours, adjusted for gestational age and renal function.

Dosage for Pregnant Women

Pregnancy Category B: Limited data; use only if benefits outweigh risks. Consult an infectious disease specialist or obstetrician.

Dosage Adjustments

Renal Impairment:

• CrCl 10–30 mL/min: Reduce to 50% of normal dose.
• CrCl <10 mL/min: Reduce to 25% and monitor levels.

Hepatic Impairment: No adjustment needed, but monitor for toxicity.

Elderly: Start with lower doses (e.g., 1 g every 12 hours); adjust based on renal function.

Additional Considerations

• Administer this active ingredient IV over 20–60 minutes or IM as a deep injection.
• Monitor renal function and adjust dose if creatinine clearance changes.

How to Use Aztreonam

Administration: Reconstitute powder with sterile water or saline (e.g., 10 mL per 1 g) and administer IV over 20–60 minutes or IM; rotate injection sites to prevent irritation.

Timing: Dose every 6–12 hours as prescribed, maintaining consistent intervals.

Monitoring: Watch for signs of rash, diarrhea, or injection site reactions.

Additional Tips:

• Use a new needle and syringe for each dose to prevent contamination.
• Report severe abdominal pain or fever immediately.

Contraindications for Aztreonam

• Patients with hypersensitivity to Aztreonam or other monobactams.
• Patients with a history of severe allergic reactions to beta-lactam antibiotics (caution advised).

Warnings & Precautions for Aztreonam

General Warnings

Allergic Reactions: Risk of anaphylaxis or cross-reactivity with other beta-lactams; monitor for rash or swelling.

Clostridium difficile Infection: Diarrhea may indicate pseudomembranous colitis; discontinue if severe.

Renal Toxicity: Elevated creatinine or oliguria; monitor renal function.

Superinfection: Risk of fungal or resistant bacterial overgrowth; assess during prolonged use.

Neuromuscular Effects: Rare seizures or weakness; use cautiously in patients with renal impairment.

Use in Specific Populations

Pregnancy: Category B; limited human data; use only if necessary.

Breastfeeding: Excreted in breast milk; use with caution and monitor infant.

Elderly: Increased risk of renal side effects; adjust dose and monitor closely.

Children: Approved for 1 month and older; monitor growth and development.

Renal/Hepatic Impairment: Adjust dose in renal failure; monitor liver function if prolonged use.

Additional Precautions

• Inform your doctor about kidney disease, allergies, or prior antibiotic reactions before starting this medication.
• Avoid concurrent nephrotoxic drugs unless benefits outweigh risks.

Overdose and Management of Aztreonam

Overdose Symptoms

Overdose may cause:

• Nausea, vomiting, or diarrhea.
• Neuromuscular irritability (e.g., tremors, seizures).
• Renal dysfunction or electrolyte imbalance.

Immediate Actions

Contact Emergency Services: Call 911 or seek immediate medical help.

Supportive Care: Provide hydration, monitor renal function, and administer anticonvulsants if seizures occur.

Monitor: Check creatinine clearance, electrolytes, and neurological status for 24–48 hours.

Additional Notes

• Overdose is rare with proper dosing; store securely.
• Report persistent symptoms (e.g., confusion, rash) promptly.

Side Effects of Aztreonam

Common Side Effects

• Diarrhea (5–10%, often mild)
• Injection site pain (5–8%, related to IM use)
• Rash (3–7%, typically self-limiting)
• Nausea (2–5%, manageable with food)

These effects may decrease with continued use.

Serious Side Effects

Allergic: Severe rash, swelling, or difficulty breathing (anaphylaxis).

Gastrointestinal: Persistent diarrhea with blood or mucus (C. difficile).

Renal: Reduced urine output or swelling (renal failure).

Neurological: Seizures or severe headache.

Additional Notes

• Regular monitoring for renal function and allergic reactions is recommended.
• Report any unusual symptoms (e.g., fever, jaundice) immediately.

Drug Interactions with Aztreonam

This active ingredient may interact with:

Aminoglycosides: Enhanced nephrotoxicity; monitor renal function if combined.

Probenecid: Increases Aztreonam levels by reducing renal excretion; adjust dose.

Warfarin: Potential increase in bleeding risk; monitor INR.

Loop Diuretics: May exacerbate renal effects; use cautiously.

Patient Education or Lifestyle

Pharmacokinetics of Aztreonam

Absorption: Poor oral bioavailability; peak plasma concentration at 1–2 hours post-IM, 30 minutes post-IV.

Distribution: Volume of distribution ~0.2 L/kg; 56–60% protein-bound; penetrates cerebrospinal fluid with inflammation.

Metabolism: Minimal hepatic metabolism; excreted largely unchanged.

Excretion: Primarily renal (60–70% unchanged via glomerular filtration); half-life 1.7–2.9 hours, extended in renal impairment.

Half-Life: 1.7–2.9 hours (up to 6–8 hours in severe renal failure).

Pharmacodynamics of Aztreonam

This drug exerts its effects by:

Binding to penicillin-binding protein 3 (PBP3), inhibiting peptidoglycan cross-linking in Gram-negative bacteria.

Causing cell wall weakening and lysis, effective against Pseudomonas aeruginosa and Enterobacteriaceae.

Offering a beta-lactam structure with low cross-reactivity to penicillins, ideal for allergic patients.

Demonstrating concentration-dependent killing, with efficacy enhanced by prolonged infusion in severe infections.

Storage of Aztreonam

Temperature: Store at 20–25°C (68–77°F); protect from moisture.

Protection: Keep in original carton until use to shield from light.

Safety: Store out of reach of children.

Disposal: Dispose of unused vials per local regulations or consult a pharmacist.

Frequently Asked Questions (FAQs)

Q: What does Aztreonam treat?
A: This medication treats UTIs, pneumonia, and intra-abdominal infections.

Q: Can this active ingredient cause diarrhea?
A: Yes, diarrhea is a risk; report persistent or bloody stools immediately.

Q: Is Aztreonam safe for children?
A: Approved for 1 month and older; consult a pediatrician.

Q: How is this drug taken?
A: Via IV or IM injection, as directed by a healthcare provider.

Q: How long is Aztreonam treatment?
A: Typically 7–14 days, depending on infection severity.

Q: Can I use Aztreonam if allergic to penicillin?
A: Often safe, but consult your doctor to confirm.

Regulatory Information

This medication is approved by:

• U.S. Food and Drug Administration (FDA): Approved in 1986 (Azactam) for Gram-negative infections.
• European Medicines Agency (EMA): Approved for similar indications.
• Other Agencies: Approved globally for bacterial infections; consult local guidelines.

References

1. U.S. Food and Drug Administration (FDA). (2023). Azactam (Aztreonam) Prescribing Information.
   • Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
2. European Medicines Agency (EMA). (2023). Aztreonam Summary of Product Characteristics.
   • EMA’s comprehensive information on the medication’s indications and precautions in Europe.
3. National Institutes of Health (NIH). (2023). Aztreonam: MedlinePlus Drug Information.
   • NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
4. World Health Organization (WHO). (2023). WHO Model List of Essential Medicines: Aztreonam.
   • WHO’s inclusion of Aztreonam for severe bacterial infections.
5. Journal of Antimicrobial Chemotherapy. (2021). Aztreonam in Gram-Negative Infections.
   • Peer-reviewed article on Aztreonam efficacy (note: access may require a subscription).