Cefiderocol (marketed as Fetroja®) is a relatively new, siderophore‐based cephalosporin antibiotic that has gained attention for its activity against a wide spectrum of multidrug‑resistant Gram‑negative bacteria.
1. What It Is
| Feature |
Details |
| Drug class |
β‑lactam / cephalosporin (siderophore cephalosporin) |
| Mechanism of action |
• Binds to iron‑binding proteins (transferrin) that bacteria use to import iron.
• The iron–cefiderocol complex is actively transported across the bacterial outer membrane (the “Trojan horse” approach).
• Once inside, cefiderocol inhibits penicillin‑binding proteins, disrupting cell‑wall synthesis. |
| Spectrum |
Highly potent against many carbapenem‑resistant organisms, including:
• Pseudomonas aeruginosa (including carbapenem‑resistant strains)
• Acinetobacter baumannii (including carbapenem‑resistant isolates)
• Enterobacter cloacae, Klebsiella pneumoniae (including those producing extended‑spectrum β‑lactamases and carbapenemases)
• Some Stenotrophomonas maltophilia and Moraxella species.
Not active against Gram‑positive organisms or anaerobes. |
| Formulation |
IV injection (20 mg/mL, 10 mL vial). |
| Pharmacokinetics |
• Oral absorption is negligible (not used orally).
• Renally cleared; dose adjustment is required for reduced kidney function.
• Half‑life ≈ 2 h; steady state is reached quickly with continuous infusion. |
2. Approved Indications (U.S. FDA)
| Indication |
Typical Use |
| Hospital‑acquired bacterial pneumonia (HAP) / ventilator‑associated bacterial pneumonia (VAP) |
Cefiderocol 2 g IV every 8 h, 2 h infusion (or 2 g q8h continuous). 7‑14 days, depending on clinical response. |
| Complicated urinary tract infection (cUTI) and acute pyelonephritis |
2 g IV q8h, 2 h infusion (or continuous). 7‑10 days. |
| Complicated intra‑abdominal infections (cIAI) |
2 g IV q8h. 7‑10 days. |
| Bacteremia and other serious infections caused by susceptible Gram‑negative organisms when no other appropriate option exists. |
The drug may also be used off‑label for other serious infections caused by susceptible organisms, guided by susceptibility testing and clinical judgment.
3. How It’s Administered
- IV infusion: The standard regimen is 2 g over 2 hours, every 8 hours (q8h). Continuous infusion is an alternative and can maintain therapeutic concentrations, especially against organisms with high MICs or in patients with augmented renal clearance.
- Dosing adjustments: Based on creatinine clearance (CrCl). For instance: <10 mL/min → 1 g q24h; 10–50 mL/min → 1 g q12h; >50 mL/min → 2 g q8h. Always refer to the prescribing information for the most current guidelines.
4. What It’s For
Cefiderocol is primarily reserved for serious infections caused by multidrug‑resistant (MDR) Gram‑negative bacteria when other treatment options are limited or contraindicated. It’s particularly valuable for:
- Carbapenem‑resistant Pseudomonas aeruginosa (CR‑Pseudomonas)
- Carbapenem‑resistant Acinetobacter baumannii (CR‑Acinetobacter)
- Carbapenem‑resistant Enterobacterales (CRE) with carbapenemase production (KPC, NDM, VIM, OXA‑48, etc.)
- Some difficult-to-treat Enterobacter or Klebsiella species
5. Common Side Effects
| Symptom |
Frequency |
Notes |
| Diarrhea |
~10–20 % |
May be mild to moderate; monitor for Clostridioides difficile colitis. |
| Nausea / vomiting |
~5–10 % |
Antiemetics can be given prophylactically. |
| Hypersensitivity reactions |
<5 % |
Includes urticaria, rash, anaphylaxis. |
| Elevated liver enzymes |
<5 % |
Check baseline LFTs and monitor if clinically indicated. |
| Electrolyte disturbances (e.g., hypokalemia) |
<5 % |
Common in ICU patients; monitor electrolytes. |
| Hematologic changes (e.g., neutropenia) |
Rare |
Monitor CBC in prolonged therapy. |
Most adverse events are mild and manageable. Serious hypersensitivity reactions are rare but require immediate discontinuation and supportive care.
6. Drug Interactions
- Renal‑eliminated drugs: Cefiderocol is mainly cleared renally, so drugs that compete for renal excretion (e.g., certain antiepileptics, metformin, certain antibiotics) can lead to increased levels of either drug. Monitor renal function and adjust doses as needed.
- Other β‑lactams: No clinically significant pharmacodynamic interaction, but overlapping toxicity (e.g., nephrotoxicity) can occur with other nephrotoxic agents.
- Cimetidine / Proton pump inhibitors: Generally no interaction, but they can affect absorption of other oral drugs; not relevant to IV cefiderocol.
- Antiepileptic drugs: Some may induce hepatic enzymes that could modestly affect cefiderocol metabolism; usually negligible.
Tip: Always consult a pharmacist or check the drug’s prescribing information for any updates on drug‑drug interactions.
7. Why It Matters
- Novel mechanism: The siderophore strategy bypasses many efflux and permeability mechanisms that render other β‑lactams ineffective.
- High stability: Cefiderocol is resistant to most β‑lactamases, including carbapenemases.
- Clinical trials: Studies such as the CREDIBLE‑ICU and CREDIBLE‑UTI trials showed non‑inferiority to best‑available therapy for MDR infections, with comparable safety profiles.
8. Key Points to Remember
- Use sparingly: Reserve for infections caused by organisms with limited treatment options; antimicrobial stewardship is essential.
- Dose adjust for renal function: Because of its renal clearance, improper dosing can lead to subtherapeutic levels or toxicity.
- Monitor: Watch for signs of superinfection (e.g., C. difficile), liver function, electrolytes, and renal function during therapy.
- Check susceptibility: In vitro susceptibility testing (e.g., MIC ≤ 2 mg/L) is recommended before initiating therapy; some isolates may show reduced susceptibility.
- No oral formulation: It must be administered intravenously.
Quick Reference Table
| Infection |
Typical Dose |
Frequency |
Key Notes |
| HAP/VAP |
2 g IV |
q8h (or continuous) |
7‑14 days |
| cUTI / pyelonephritis |
2 g IV |
q8h |
7‑10 days |
| cIAI |
2 g IV |
q8h |
7‑10 days |
| Severe bacteremia (susceptible MDR) |
2 g IV |
q8h |
Duration per clinical judgment |
Bottom line
Cefiderocol is a powerful, IV‑only cephalosporin with a unique siderophore mechanism that gives it excellent activity against many carbapenem‑resistant Gram‑negative pathogens. It’s a crucial tool in the armamentarium against MDR infections, but like all antibiotics, it should be used judiciously, with dose adjustments for renal function, and under the guidance of infectious disease specialists and pharmacists.