About This Dosing Guide
This guide provides supplementary information for the Inflectra (infliximab-dyyb) Dosing Calculator. It outlines the tool’s functions, the data it provides, and key clinical considerations based on the FDA-approved Prescribing Information. It is intended for healthcare professionals as a supportive resource and is not a substitute for clinical judgment or the official product labeling.
Calculator Outputs Explained
Upon entering the required patient data, the calculator provides the following key outputs for administration planning:
- Calculated Dose: The total dose in milligrams (mg) based on patient weight and the selected mg/kg regimen.
- Number of Vials: The total number of 100 mg single-dose vials required for the calculated dose, rounded up to the nearest whole vial.
- Total Volume to Withdraw: The total volume in milliliters (mL) to be withdrawn from the reconstituted vials (10 mL per vial).
- Final Concentration: The final concentration (mg/mL) of infliximab-dyyb in the specified total infusion volume (default 250 mL).
- Infusion Protocol: A reference for a standard 2-hour infusion titration schedule.
How to Use the Calculator
To ensure accurate calculations, follow these steps:
- Enter Patient Weight: Input the patient’s weight and select the appropriate unit (kg or lbs). The tool will automatically convert lbs to kg for the calculation.
- Select Clinical Indication: Choose the FDA-approved indication for which Inflectra is being prescribed. This determines the approved dosing regimens.
- Choose Dosing Regimen: Select either the “Induction” or “Maintenance” phase of treatment.
- Consider Dose Escalation: For applicable indications (e.g., Crohn’s Disease, RA), you can select the dose escalation option (10 mg/kg) if clinically appropriate due to loss of response.
- Confirm Infusion Volume: The tool defaults to a standard 250 mL total infusion volume. Adjust if a different volume is used clinically.
Dosing Overview by Indication
The following table summarizes the standard dosing schedules for Inflectra based on the Prescribing Information.
| Indication | Induction Dosing | Maintenance Dosing |
|---|---|---|
| Crohn’s Disease (Adult & Pediatric) | 5 mg/kg at Weeks 0, 2, and 6 | 5 mg/kg every 8 weeks |
| Ulcerative Colitis (Adult & Pediatric) | 5 mg/kg at Weeks 0, 2, and 6 | 5 mg/kg every 8 weeks |
| Rheumatoid Arthritis (in combination with methotrexate) | 3 mg/kg at Weeks 0, 2, and 6 | 3 mg/kg every 8 weeks (may increase dose or shorten interval) |
| Ankylosing Spondylitis | 5 mg/kg at Weeks 0, 2, and 6 | 5 mg/kg every 6 weeks |
| Psoriatic Arthritis | 5 mg/kg at Weeks 0, 2, and 6 | 5 mg/kg every 8 weeks |
| Plaque Psoriasis | 5 mg/kg at Weeks 0, 2, and 6 | 5 mg/kg every 8 weeks |
For some patients who experience a loss of response, dose escalation to 10 mg/kg or interval adjustment may be considered for certain indications. Always refer to the full Prescribing Information.
Switching to Inflectra
The decision to switch a patient to Inflectra from another biologic (including the reference product) rests with the treating healthcare provider. Considerations should include the patient’s clinical history, disease activity, and previous response to therapy. Refer to guidance from professional societies and the full Prescribing Information when making a transition in therapy.
Missed Dose Information
If a patient misses a scheduled infusion of Inflectra, the missed dose should be administered as soon as possible. Subsequently, the maintenance dosing schedule should be re-established from the date of this infusion to maintain the correct therapeutic interval. For example, if a patient on an 8-week schedule receives a missed dose, their next dose would be due 8 weeks later.
Important Safety Alerts
Patients treated with infliximab products are at an increased risk for developing serious infections that may lead to hospitalization or death. These include tuberculosis (TB), bacterial sepsis, invasive fungal infections, and other opportunistic infections. Treatment should not be initiated in patients with an active infection. Patients should be tested for latent TB and treated if positive prior to starting Inflectra.
Lymphoma and other malignancies, some fatal, have been reported in children and adolescent patients treated with TNF blockers, including infliximab products.
This is not a complete list of risks. Please consult the full Prescribing Information for all warnings and precautions.
Frequently Asked Questions
The tool allows you to input weight in either unit. If you enter a weight in lbs, it is automatically converted to kg (using the conversion factor 1 kg ≈ 2.20462 lbs) for the dose calculation, as all dosing guidelines are in mg/kg.
According to the Prescribing Information, dose escalation to 10 mg/kg may be considered for patients with Crohn’s Disease, Ulcerative Colitis, or Rheumatoid Arthritis who have an inadequate response or lose response over time.
Yes. For patients with Rheumatoid Arthritis, if an adequate response is not achieved, the maintenance dose may be increased to 10 mg/kg or the dosing interval may be shortened to as frequently as every 4 weeks.
It divides the total calculated dose (in mg) by 100 mg (the amount per vial) and then rounds the result up to the nearest whole number (e.g., a calculated dose of 340 mg would require 4 vials).
The calculator displays a standard 2-hour infusion rate titration schedule. The rate is initiated at 60 mL/hr, increased to 120 mL/hr, and then finished at 150 mL/hr. This may be adjusted based on patient tolerance. Rapid 1-hour infusions may be an option for certain patients who have previously tolerated treatment.
Induction dosing is a series of initial, closely spaced doses (typically at weeks 0, 2, and 6) designed to rapidly achieve therapeutic drug levels. Maintenance dosing refers to the ongoing, regularly scheduled infusions that maintain those levels over the long term.
No. This tool is for informational and educational purposes only. It is not a substitute for clinical judgment. Healthcare professionals must consult the full, most current Prescribing Information before prescribing or administering Inflectra.
The calculations are based on the Inflectra (infliximab-dyyb) Prescribing Information dated March 2024. Always verify with the latest official documentation.
References
- Inflectra (infliximab-dyyb) Full Prescribing Information. U.S. Food and Drug Administration. Revised: 03/2024.
- Inflectra HCP Website. Pfizer Inc.
- Drugs@FDA Database. U.S. Food and Drug Administration.
- Lichtenstein GR, Loftus EV, Isaacs KL, et al. ACG Clinical Guideline: Management of Crohn’s Disease in Adults. Am J Gastroenterol. 2018;113(4):481-517.
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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