About This Calculator
The Tepezza (teprotumumab-trbw) Dosing and Infusion Calculator is designed for healthcare professionals to support the administration process for patients with Thyroid Eye Disease (TED). This tool determines the correct dosage, number of vials, and infusion parameters based on patient weight and the specific infusion number in the treatment course. It is intended for informational purposes and should not replace clinical judgment or the official Prescribing Information.
Calculator Outputs Explained
After entering the required patient data, the calculator provides the following key outputs for safe and accurate administration:
- Calculated Total Dose (mg): The precise weight-based dose of teprotumumab-trbw for the selected infusion.
- Number of 500 mg Vials Required: The total number of vials needed for reconstitution, calculated by rounding up the required dose to the nearest 500 mg increment.
- Total Volume to Withdraw (mL): The volume of reconstituted solution (50 mg/mL) to be withdrawn from the vials for dilution in an IV bag.
- Infusion Parameters: Recommended final volumes and infusion rates (in mL/hr) for both 100 mL and 250 mL 0.9% Sodium Chloride IV bags, adjusted for the appropriate infusion duration (90 or 60 minutes).
How to Use the Tool
To ensure accurate calculations, follow these simple steps:
- Enter Patient Weight: Input the patient's current body weight. You can toggle between kilograms (kg) and pounds (lbs) for convenience.
- Select Infusion Number: Choose the appropriate infusion from the dropdown menu. The selection determines the dose per kilogram (10 mg/kg for the first infusion, 20 mg/kg for subsequent infusions) and the infusion duration.
- Review Results: The tool will automatically calculate and display the dosing and preparation details. Always double-check these calculations against institutional protocols and the official prescribing information before administration.
Dosing and Administration Overview
Tepezza is administered as an intravenous infusion once every three weeks for a total of eight infusions. The dosing schedule is biphasic:
| Infusion | Dose | Infusion Duration |
|---|---|---|
| Infusion 1 | 10 mg/kg | 90 minutes |
| Infusion 2 | 20 mg/kg | 90 minutes |
| Infusions 3 through 8 | 20 mg/kg | 60 minutes (if prior infusions were tolerated) |
Each 500 mg vial of Tepezza should be reconstituted with 10 mL of Sterile Water for Injection, USP, to yield a final concentration of 50 mg/mL. The calculated volume is then transferred to an IV bag containing 0.9% Sodium Chloride Injection, USP.
Switching Medications
There is no specific guidance on switching to or from Tepezza from other therapies for Thyroid Eye Disease. Treatment decisions, including initiation, discontinuation, or changes in therapy, should be made by a qualified healthcare professional based on a comprehensive clinical evaluation of the patient.
Missed Dose Protocol
If a planned infusion of Tepezza is missed, it should be administered as soon as possible. The subsequent infusion should be rescheduled to maintain a 3-week interval between doses. It is important to complete the full course of eight infusions to achieve the intended therapeutic outcome.
Safety Information
This tool does not replace the full Prescribing Information, which is the sole authoritative source for all safety, dosing, and administration guidelines.
Healthcare professionals must be aware of important safety considerations, including warnings and precautions for infusion-related reactions, exacerbation of pre-existing inflammatory bowel disease, hyperglycemia, and hearing impairment. All calculations performed by this tool must be independently verified prior to drug preparation and administration.
Frequently Asked Questions (FAQ)
What is the concentration of reconstituted Tepezza?
After reconstituting a 500 mg vial with 10 mL of Sterile Water for Injection, the resulting concentration is 50 mg/mL.
How is the number of required vials determined?
The total milligram dose is divided by 500 mg (the amount per vial). The result is always rounded up to the next whole number to ensure enough drug is available for the calculated dose.
What should I do if a patient's weight changes during the treatment course?
The dose of Tepezza is based on the patient's actual body weight. It is recommended to use the patient's current weight to calculate the dose before each infusion.
Why is the infusion duration shortened for infusions 3 through 8?
The infusion duration can be decreased from 90 minutes to 60 minutes for the third through eighth infusions if the patient has tolerated the prior infusions without any significant adverse reactions.
Can Tepezza be mixed with other IV fluids besides 0.9% Sodium Chloride?
No, the prescribing information specifies that the calculated volume of reconstituted Tepezza should only be diluted in an IV infusion bag of 0.9% Sodium Chloride Injection, USP.
Is there a maximum dose of Tepezza?
The prescribing information does not define a maximum dose. Dosing is strictly based on the patient's weight at either 10 mg/kg or 20 mg/kg depending on the infusion number.
How long is the diluted Tepezza solution stable?
The diluted solution in the IV bag should be administered immediately. If immediate use is not possible, it can be stored under refrigeration (2°C to 8°C or 36°F to 46°F) for up to 4 hours. Do not freeze.
What if the calculated volume to withdraw is very small or large?
The calculator provides the exact volume based on the formula. Always use calibrated syringes to ensure accuracy when withdrawing the reconstituted solution, regardless of the volume.
References
- TEPEZZA® (teprotumumab-trbw) Prescribing Information. U.S. Food and Drug Administration.
- Dosing and Administration Information. TEPEZZA® HCP Website.
- Douglas RS, Kahaly GJ, Patel A, et al. Teprotumumab for the Treatment of Active Thyroid Eye Disease. N Engl J Med. 2020;382(4):341-352.
- Smith TJ, Kahaly GJ, Ezra DG, et al. Teprotumumab for Thyroid-Associated Ophthalmopathy. N Engl J Med. 2017;376(18):1748-1761.
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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