About this Calculator

The Cefiderocol Dose Calculator is a clinical support tool designed to help healthcare professionals determine the appropriate dosing regimen for cefiderocol (Fetroja®) based on a patient's renal function. It utilizes the Cockcroft-Gault equation to estimate creatinine clearance (CrCl) and provides recommendations for patients with normal renal function, augmented renal clearance, renal impairment, and those on renal replacement therapy.

This information is for educational purposes and should not replace clinical judgment or the official prescribing information.

Outputs Explained

After entering the required patient data, the calculator provides a clear dosing recommendation that includes:

• Calculated CrCl: The estimated creatinine clearance in mL/min, which is the primary determinant for dosing.
• Recommended Dose: The specific amount of cefiderocol (in grams) to be administered.
• Dosing Frequency: The interval at which the dose should be given (e.g., every 6, 8, or 12 hours).
• Infusion Duration: Cefiderocol requires a standard infusion time of 3 hours for all doses.
• Rationale: A brief note explaining the basis for the recommendation, such as the patient's CrCl range or RRT status.

How to Use the Calculator

To calculate the appropriate cefiderocol dose, follow these steps:

1. Enter Patient Demographics: Input the patient's age, actual body weight (in kg or lbs), and sex.
2. Provide Serum Creatinine (SCr): Enter the patient's most recent SCr level, selecting the correct units (mg/dL or µmol/L).
3. Select Renal Replacement Therapy (RRT): Choose the appropriate RRT status. If "None" is selected, the tool calculates CrCl.
   • If Intermittent Hemodialysis (IHD) is selected, a standard recommendation for IHD patients is provided.
   • If Continuous Renal Replacement Therapy (CRRT) is selected, a new field will appear to enter the CRRT effluent rate in mL/kg/hr.
4. Calculate: Click the "Calculate Dose" button to view the recommendation.

Dosing Overview

All recommended doses of cefiderocol should be administered as an intravenous (IV) infusion over 3 hours. Dosing is based on renal function as follows:

*On hemodialysis days, administer the dose as soon as possible after the dialysis session is complete.

Switching Therapy

The decision to switch to or from cefiderocol therapy should be based on a comprehensive clinical assessment, including microbiological culture and susceptibility results, the patient's clinical response, and the source of infection. Cefiderocol is often reserved for treating complicated urinary tract infections (cUTI) and hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP) caused by susceptible Gram-negative microorganisms when limited or no alternative treatment options are available.

Missed Dose

If a dose of cefiderocol is missed, it should be administered as soon as possible. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. The patient should continue with their regular dosing schedule. Two doses should not be administered at the same time to make up for a missed dose. Always consult with a pharmacist or physician for specific guidance.

Safety Alerts

Increased All-Cause Mortality in Patients with Carbapenem-Resistant Gram-Negative Bacterial Infections: An increase in all-cause mortality was observed in patients treated with cefiderocol compared to best available therapy in a multinational, randomized, open-label trial in critically ill patients with carbapenem-resistant Gram-negative bacterial infections. The cause of the increase has not been established. Cefiderocol's use should be reserved for patients who have limited or no alternative treatment options. For full details, consult the official prescribing information.

Frequently Asked Questions

What formula does this calculator use for CrCl estimation?

The calculator uses the Cockcroft-Gault equation to estimate creatinine clearance. The formula is: CrCl (male) = [(140 - Age) * Weight (kg)] / [72 * SCr (mg/dL)]. For females, the result is multiplied by 0.85.

Why is patient sex a required input?

The Cockcroft-Gault formula includes a correction factor for females (multiplication by 0.85) to account for differences in muscle mass and creatinine production compared to males, making it a crucial variable for an accurate estimation.

How does the calculator handle patients on intermittent hemodialysis (IHD)?

When IHD is selected, the calculator bypasses the CrCl calculation and provides the standard recommended dose for IHD patients, along with specific instructions to administer the dose after the dialysis session on dialysis days.

What is Augmented Renal Clearance (ARC) and how does it affect dosing?

ARC is a condition where a patient's kidneys clear substances faster than normal, defined here as a CrCl of 120 mL/min or greater. These patients require a more frequent dosing interval (every 6 hours) to maintain adequate therapeutic drug concentrations.

What is the recommended infusion duration for all cefiderocol doses?

All doses of cefiderocol, regardless of the amount or frequency, should be administered as an intravenous infusion over 3 hours.

Does this calculator use actual, ideal, or adjusted body weight?

The calculator is designed to use the patient's actual body weight as entered by the user, which is standard for the Cockcroft-Gault equation. Clinical judgment should be applied in cases of extreme obesity.

Can this calculator be used for pediatric patients?

No, this calculator is intended for adult patients. The Cockcroft-Gault equation and the dosing regimens are based on adult clinical trial data. Pediatric dosing requires different considerations.

Is this tool a substitute for the official FDA label?

Absolutely not. This tool is for informational and educational purposes only. It is not a substitute for professional clinical judgment, and all results should be verified against the most current official prescribing information for Fetroja® (cefiderocol).

References

For complete and detailed information, please consult the following high-authority sources:

• Fetroja® (cefiderocol) US Prescribing Information. Shionogi Inc. Access the latest label at the FDA Drugs@FDA Database.
• Fetroja® (cefiderocol) Official HCP Website. www.fetroja.com
• European Medicines Agency (EMA). Fetcroja (cefiderocol) Summary of Product Characteristics (SmPC). Available at the EMA website.