About This Tool
The Tirzepatide Titration Calculator is a clinical support tool designed for healthcare professionals to model standard dosing schedules for tirzepatide (Mounjaro® and Zepbound®). It helps visualize the dose escalation pathway for initiating therapy in new patients or continuing titration for existing patients, aiming to balance efficacy with tolerability.
Understanding the Outputs
After entering the required patient information, the calculator generates a clear, table-based titration schedule with the following details:
- Dose Level: The specific milligram strength for each step of the titration (e.g., 2.5 mg, 5 mg).
- Start Date: The calculated date on which the patient should begin each new dose level.
- End Date: The date the patient completes the standard duration at that dose level. For the target maintenance dose, this will show as “Ongoing”.
- Duration: The length of time spent at each dose, typically a minimum of 4 weeks. The tool allows for extending this duration to manage side effects.
- Notes: Important context, such as identifying the non-therapeutic starting dose or the selected target maintenance dose.
How to Use the Calculator
To generate a dosing schedule, follow these steps:
- Select Indication for Use: Choose between “Type 2 Diabetes” or “Chronic Weight Management”.
- Choose Calculation Mode: Select “New Patient” for those initiating tirzepatide or “Existing Patient” for those already on a dose and needing to continue titration.
- Enter Dates and Doses:
- For a new patient, provide the desired Treatment Start Date.
- For an existing patient, select their Current Dose and the date they started that dose.
- Set Target Dose: Choose the desired maintenance dose from the dropdown menu (5 mg to 15 mg).
- Calculate: Click the “Calculate Schedule” button to generate the titration plan.
Dosing Overview
The standard tirzepatide titration schedule is designed to mitigate gastrointestinal side effects by gradually increasing the weekly dose. The schedule is the same for both Mounjaro® and Zepbound®.
| Step | Dose | Duration | Purpose |
|---|---|---|---|
| 1 (Initiation) | 2.5 mg once weekly | 4 weeks | Tolerability (not for glycemic/weight control) |
| 2 (Titration) | 5 mg once weekly | At least 4 weeks | First therapeutic dose |
| 3 (Titration) | 7.5 mg once weekly | At least 4 weeks | Increase dose as needed |
| 4 (Titration) | 10 mg once weekly | At least 4 weeks | Increase dose as needed |
| 5 (Titration) | 12.5 mg once weekly | At least 4 weeks | Increase dose as needed |
| 6 (Maintenance) | 15 mg once weekly | Ongoing | Maximum recommended dose |
Switching From Other GLP-1 Agonists
When switching a patient from another GLP-1 receptor agonist (e.g., semaglutide, liraglutide) to tirzepatide, treatment should be initiated at the starting dose of 2.5 mg once weekly. The previous GLP-1 agonist should be discontinued before starting tirzepatide. A washout period is not typically required, and tirzepatide can be started after the last dose of the previous agent would have been due. This process must be guided by clinical judgment.
Missed Dose Guidance
The calculator includes a feature to provide guidance based on the time elapsed since the last administration. The recommendations align with the official prescribing information:
- Less than 4 days (96 hours) since missed dose: Administer the dose as soon as possible. Resume the regular weekly schedule.
- More than 4 days since missed dose: Skip the missed dose and administer the next dose on the regularly scheduled day.
- More than 2 consecutive weeks missed: Re-initiation of therapy may be required. Consult the prescribing information, which may recommend restarting at the 2.5 mg induction dose.
Patients should be advised not to administer two doses within 3 days (72 hours) of each other.
Safety Alerts
Boxed Warning: Risk of Thyroid C-Cell Tumors
Tirzepatide is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). In studies with rats, tirzepatide caused thyroid C-cell tumors. The relevance to humans is unknown. Patients should be counseled on the potential risk and symptoms of thyroid tumors.
Other important safety considerations include the risk of pancreatitis, acute gallbladder disease, hypoglycemia (especially when used with insulin or sulfonylureas), and potential drug interactions due to delayed gastric emptying, which can affect the absorption of oral medications.
Frequently Asked Questions
1. What is the difference between the ‘New Patient’ and ‘Existing Patient’ modes?
‘New Patient’ mode starts the schedule from the initial 2.5 mg dose. ‘Existing Patient’ mode allows you to begin the schedule from a dose the patient is already taking, such as 5 mg or 7.5 mg, to calculate the dates for subsequent dose increases.
2. Can I use this calculator for semaglutide (Ozempic/Wegovy) or other GLP-1s?
No. This calculator is specifically designed for the tirzepatide titration schedule as per the prescribing information for Mounjaro® and Zepbound®. Other medications have different dosing and titration schedules.
3. Why is the starting dose 2.5 mg if it’s not therapeutic?
The 2.5 mg starting dose is for tolerability purposes only. It allows the body to acclimate to the medication, reducing the incidence and severity of gastrointestinal side effects like nausea before increasing to therapeutic dose levels.
4. The calculator output has an “Extend This Dose” button. What does this do?
This interactive feature, visible in the tool’s output, allows you to simulate delaying a dose increase. If a patient is experiencing side effects, a clinician may choose to keep them on their current dose for an additional 4 weeks (or more). The button recalculates the entire schedule to reflect this extension.
5. What happens if I select a target dose lower than 15 mg?
The calculator will generate the titration schedule up to and including your selected target dose. The schedule will stop there, marking that dose as the “Target maintenance dose.”
6. Does this calculator provide medical advice?
No. This tool is for educational and modeling purposes only. It is not a substitute for professional clinical judgment. All treatment decisions should be made by a qualified healthcare provider based on a full assessment of the individual patient.
7. How does the “Missed Dose Guidance” feature work?
It calculates the number of days between the last dose date you enter and today’s date. Based on this duration, it provides a recommendation that aligns with the FDA-approved prescribing information for managing a missed dose.
8. Does tirzepatide interact with oral medications?
Yes, potentially. Tirzepatide delays gastric emptying, which can alter the absorption of co-administered oral medications. This is particularly important for drugs with a narrow therapeutic index or for oral contraceptives. Counsel patients accordingly.
References
- Mounjaro® (tirzepatide) Prescribing Information. U.S. Food and Drug Administration.
- Zepbound™ (tirzepatide) Prescribing Information. U.S. Food and Drug Administration.
- LillyMedical – Mounjaro Professional Resources. Eli Lilly and Company.
- LillyMedical – Zepbound Professional Resources. Eli Lilly and Company.
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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