Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Aztreonam

Aztreonam

Monobactam (IV, inhaled)

Gram-negativePenicillin allergyΞ²-lactam

Indication

Pseudomonas in CF (inhaled/IV) β€’ GNR pneumonia/UTI/bacteremia β€’ surgical de-escalation from broader

At a glance

INDICATIONS (CORE USE)

Gram-negative only β€” **safe in many penicillin allergies** (still monitor); no gram-positive/anaerobe coverage.

ADULT DOSE (STANDARD)

1–2 g IV q6–8h; severe 2 g q6h; inhaled for chronic pseudomonas in CF

MAX DOSE

~8 g/day adult in divided doses (institution)

Route

IV, IM, inhaled (CF)

PEDIATRIC DOSE

Weight-based q6–8h per pediatric reference

Do not miss

Must-not-miss safety points

Major warning

- Ξ²-lactam class β€” **rare cross-reactivity** with ceftazidime (side chain) in severe cephalosporin allergy - **No staph/strep/anaerobe** β€” catastrophic monotherapy for typical cellulitis/endocarditis - Renal adjustment - Resistance β€” inducible chromosomal beta-lactamases in some organisms

Indications

USE IF: Susceptible gram-negative infection when beta-lactam allergy history complicates penicillin/ceph use; CF pseudomonas protocols. AVOID IF: Polymicrobial infection needing GP/anaerobes; MRSA.

Primary

  • Susceptible gram-negative bacteremia / pneumonia / UTI when spectrum fits
  • Cystic fibrosis chronic Pseudomonas suppression (inhaled per pulmonology)

Secondary

  • Alternative in documented severe penicillin allergy when GNR targeted (allergy clinic coordination)

Other

  • Combination regimens to reduce vancomycin/neurotoxicity exposure in selected protocols (specialist)

Dosing

STANDARD (ADULT PO)

1–2 g IV q6–8h (renal adjust; inhaled CF per protocol)

ADULT DOSE

1–2 g IV q6–8h; adjust renal; inhaled dosing per CF protocol

PEDIATRIC DOSE

Per pediatric CF / sepsis dosing.

MAX DOSE

High doses in CF IV exacerbations β€” specialist.

Practical Note

Inhaled formulation distinct from IV β€” never interchange.

Warnings

Clinical warnings

  • **Ξ²-lactam allergy β€” immediate** (anaphylaxis, angioedema, bronchospasm, hypotension) β†’ **avoid** this agent; use non–β-lactam alternative
  • **Ξ²-lactam allergy β€” non-severe** (maculopapular rash without systemic anaphylaxis features) β†’ **caution**; risk/benefit + allergy/ID pathway; graded challenge or test dose **only** per protocol β€” do not dismiss automatically
  • **Neurotoxicity:** encephalopathy, confusion, myoclonus, seizures β€” **higher risk with CKD, elderly, dose accumulation** (notably cefepime, carbapenems, high-dose penicillins)
  • New CNS symptoms + renal impairment on IV Ξ²-lactam β†’ **hold dose**, check levels/exposure, rule out other causes
  • Neurotoxicity at high doses + renal failure (rare)
  • C. diff any antibiotic

Adverse effects

  • rash
  • phlebitis
  • GI upset

Contraindications

  • Hypersensitivity to aztreonam

Drug interactions

  • Aminoglycoside synergy β€” nephro watch

Special populations

Pediatrics

Weight-based q6–8h per pediatric reference

Pregnancy

Pregnancy: use if needed

Lactation

limited data β€” likely low oral absorption by infant.

Renal impairment

Dose/interval reduction CKD; HD supplemental. **CrCl scaffold (FMBM β€” titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β‰₯50** β†’ standard interval (per Adult dosing card) - **CrCl 10–50** β†’ extend interval and/or reduce dose (often q12–24h or ↓ dose β€” **product-specific**) - **CrCl <10** β†’ maximal interval extension / dose reduction; **HD: redose post-dialysis** per protocol; AKI β†’ re-estimate CrCl; **neuro signs** β†’ hold/adjust

Hepatic impairment

No routine adjustment.

Elderly

Renal dosing.

Administration

IV intermittent; inhaled with appropriate nebulizer.

Monitoring

  • Monitor: - ICU or CKD β†’ **creatinine daily** β†’ underdosing in AKI vs accumulation / **neurotoxicity** if not adjusted - New confusion / myoclonus / seizures + renal impairment on IV Ξ²-lactam β†’ **hold dose** β†’ evaluate encephalopathy - Serious GNR infection β†’ extended-infusion / pharmacy optimization per protocol - GNR cultures to confirm susceptibility - Allergy cross-reactivity documentation if cephalosporin allergy
  • Recheck: - No clinical improvement at 48–72h β†’ reassess diagnosis, resistance, source control, and drug interactions - If targets not met after reassessment of dose, organ function, and interactions β†’ escalate per protocol (DO NOT continue blindly)

Overdose / toxicity

Clinical Picture

**Life-threatening (first):** **CNS toxicity** β€” seizures, encephalopathy, agitation, myoclonus, coma (**↑ CKD, elderly, accumulation**; cefepime, carbapenems, high-dose penicillins). **Allergic:** anaphylaxis / angioedema (separate pathway). **Secondary:** nausea/vomiting/diarrhea mainly with acute massive **oral** co-ingestion or local infusion reaction.

Immediate Actions

Stop Ξ²-lactam β†’ ABCs β†’ **seizure precautions**; benzos if seizures; check renal function / dose vs CrCl; anaphylaxis β†’ epinephrine + ACLS

Antidote

No specific antidote; treat complications (e.g. anaphylaxis β†’ epinephrine per ACLS)

Decontamination

Stop infusion; recent large PO load β†’ charcoal if protected airway + early presentation

Escalation

Status epilepticus, coma, refractory seizures β†’ **ICU**; **severe CNS toxicity or AKI with accumulation β†’ consider hemodialysis** for dialyzable agents β€” nephrology + pharmacy; persistent anaphylaxis β†’ ICU

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield Summary

**GNR-only** drug. Penicillin allergy pathway β€” **not zero cross-react** with ceftazidime-allergic (side chain).

Clinical pearls

Stewardship: don’t use aztreonam empirically for typical community SSTI. CF: inhaled maintenance distinct from acute IV. *Stewardship (all antimicrobials):* Empiric choice β†’ syndrome severity + **local antibiogram**; shortest effective course.

Stewardship & safety

  • GP zero coverage
  • Ceftazidime allergy flag
  • Renal dose

Pharmacokinetics

Renal elimination; inhaled achieves high airway levels.

Mechanism of action

Monobactam β€” binds PBP-3 in gram-negatives selectively.

Common brand names

Saudi Arabia

Azactam, Aztreonam

Global

(placeholder β€” verify local formulary)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Empiric choice β†’ tie to syndrome, severity, and local antibiogram β€” not habit.
  • IV β†’ PO step-down when oral bioavailability and susceptibility allow.
  • Do not use antibiotics for uncomplicated viral illness β€” stewardship.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling

Do not miss

  • Uncomplicated viral URI/bronchitis β†’ antibiotics rarely indicated
  • Narrow or stop when susceptibilities + clinical stability allow
  • Monotherapy for β€˜cellulitis’ without covering staph β†’ failure.
  • GP zero coverage
  • Ceftazidime allergy flag
  • Renal dose