About This Calculator

The Exenatide Dose Calculator is a clinical support tool designed to help healthcare professionals determine the appropriate dosing schedule for exenatide based on the specific formulation and the patient’s renal function. It covers both immediate-release (Byetta®) and extended-release (Bydureon BCise®) options, providing guidance for therapy initiation and maintenance.

Interpreting the Results

The calculator provides clear, color-coded recommendations based on the inputs provided:

• Recommended Dose: A standard green-light result showing the correct dosage, frequency, and administration notes for the selected patient profile.
• Cautionary Warning: A yellow warning result, typically for patients with moderate renal impairment (CrCl 30-50 mL/min) using immediate-release exenatide. It advises cautious dose titration and monitoring for adverse effects.
• Not Recommended: A red danger result indicating that exenatide use is not advised for the specified patient profile, such as those with severe renal impairment (CrCl < 30 mL/min for IR, CrCl < 45 mL/min for ER).

How to Use

Follow these steps to determine the correct exenatide dose:

1. Select Formulation: Choose between “Immediate-Release (Byetta®)” and “Extended-Release (Bydureon BCise®)”.
2. Select Treatment Stage: If using the immediate-release formulation, specify whether the patient is “Initiating Therapy” or is ready for a “Maintenance” dose increase.
3. Enter Renal Function: Input the patient’s Creatinine Clearance (CrCl) in mL/min to adjust the dose for renal safety.

Dosing Overview

Byetta® (Immediate-Release)

• Initiation Dose: 5 mcg subcutaneous injection twice daily (BID), administered within 60 minutes before the morning and evening meals.
• Maintenance Dose: After one month of therapy, the dose can be increased to 10 mcg BID to further improve glycemic control, based on clinical response.
• Renal Impairment: Use with caution in patients with moderate renal impairment (CrCl 30-50 mL/min). Not recommended for patients with a CrCl below 30 mL/min.

Bydureon BCise® (Extended-Release)

• Dose: 2 mg subcutaneous injection once every 7 days (weekly). It can be administered at any time of day, with or without meals.
• Renal Impairment: Not recommended for patients with a CrCl below 45 mL/min due to insufficient clinical data in this population.

Switching Formulations

When switching a patient from Byetta® (twice-daily) to Bydureon BCise® (weekly), discontinue Byetta® and initiate Bydureon BCise® at the next scheduled dosing time. No dose tapering or washout period is required. Transient elevations in blood glucose may occur after switching.

Missed Dose Instructions

• Byetta® (Immediate-Release): If a dose is missed, the patient should skip that dose and resume their regular twice-daily schedule with the next planned dose. They should not take an extra dose.
• Bydureon BCise® (Extended-Release): If a weekly dose is missed, it should be administered as soon as it is remembered, provided the next regularly scheduled dose is at least 3 days away. Afterward, the patient can resume their normal weekly schedule. If the next dose is less than 3 days away, they should skip the missed dose and take the next dose on the regularly scheduled day.

Safety Alerts

Frequently Asked Questions (FAQ)

Why does the calculator require Creatinine Clearance (CrCl)?

Exenatide is cleared primarily by the kidneys. Impaired renal function can lead to reduced clearance and higher drug concentrations, increasing the risk of adverse events. The calculator uses CrCl to ensure the dose is safe and appropriate for the patient’s kidney function, per FDA guidelines.

What is the difference between Byetta® and Bydureon BCise®?

Byetta® is an immediate-release formulation of exenatide administered twice daily. Bydureon BCise® is an extended-release formulation administered once weekly, providing more stable drug levels over time.

Can I use this calculator for other GLP-1 agonists?

No. This tool is calibrated specifically for exenatide (Byetta® and Bydureon BCise®). Other GLP-1 receptor agonists like liraglutide, semaglutide, or dulaglutide have different dosing schedules and renal adjustment criteria.

Why is the “Treatment Stage” option only available for immediate-release exenatide?

Immediate-release exenatide (Byetta®) has a dose titration schedule, starting with 5 mcg BID and potentially increasing to 10 mcg BID. Extended-release exenatide (Bydureon BCise®) is a fixed 2 mg weekly dose without a titration period.

What does the “Caution” warning for CrCl 30-50 mL/min mean?

It signifies that while Byetta® can be used in patients with moderate renal impairment, dose escalation from 5 mcg to 10 mcg should be done carefully. These patients may have a higher risk of side effects like nausea and vomiting, which could lead to dehydration and worsen renal function.

The calculator states exenatide is “not recommended.” What should I do?

This result indicates that, based on the provided CrCl, the drug is contraindicated or not recommended by the manufacturer. You should consider alternative glucose-lowering therapies with a more favorable safety profile for the patient’s degree of renal impairment.

How should exenatide be administered?

Both formulations are given as a subcutaneous injection in the abdomen, thigh, or upper arm area. The injection site should be rotated with each dose.

Does this calculator provide pediatric dosing?

No. The safety and effectiveness of exenatide have not been established in pediatric patients, and this calculator is intended for adult dosing only.

References

1. BYETTA® (exenatide) injection Prescribing Information. U.S. Food and Drug Administration. AstraZeneca Pharmaceuticals LP.
2. BYDUREON BCISE® (exenatide extended-release) injectable suspension Prescribing Information. U.S. Food and Drug Administration. AstraZeneca Pharmaceuticals LP.
3. AstraZeneca Medical Information – BYDUREON BCISE®. AstraZeneca.
4. Drugs@FDA: FDA-Approved Drug Products. U.S. Food and Drug Administration.