About This Tool

This Xolair® Dose Calculator (Asthma) determines the appropriate subcutaneous dosage for patients aged 6 and older with moderate to severe persistent allergic asthma. Dosing is based on the patient's pre-treatment total serum IgE level and body weight, as specified in the official Prescribing Information. This tool is intended for educational and reference purposes and should not replace clinical judgment.

Outputs

Upon entering the required patient data, the calculator provides the following key outputs:

• Total Dose: The recommended dose of Xolair in milligrams (mg).
• Frequency: The administration interval, either every 2 weeks or every 4 weeks.
• Administration Details: The combination of prefilled syringes (75 mg and/or 150 mg) needed to achieve the total dose.
• Number of Injections: The total number of subcutaneous injections required per administration.

How to Use

To calculate the recommended Xolair dose, follow these steps:

1. Enter Serum IgE: Input the patient's pre-treatment total serum IgE level, measured in IU/mL. The valid range is 30 to 1500 IU/mL.
2. Enter Body Weight: Input the patient's body weight. You can toggle between kilograms (kg) and pounds (lbs). The valid weight range is 20 to 150 kg.
3. Calculate: Click the "Calculate Dose" button to view the results based on the approved dosing tables.

Dosing Overview

Xolair dosing is determined using lookup tables that correlate a patient's baseline IgE level and body weight to a specific dose and frequency. The dose is not adjusted based on changes in IgE levels or body weight during the course of treatment. Doses are administered subcutaneously every 2 or 4 weeks. The maximum recommended dose per injection site is 150 mg.

Switching and Dose Adjustments

The Xolair dose is determined at the initiation of therapy. Dose adjustments are not recommended for changes in IgE levels or minor weight fluctuations during treatment. If a significant change in body weight occurs, re-dosing based on the new weight and the original baseline IgE level may be necessary, according to the official dosing tables. This tool does not provide guidance for switching from other biologics.

Missed Dose

If a patient misses a dose of Xolair, they should be instructed to take it as soon as they remember. The subsequent doses should then be rescheduled from the date of the last administered dose to maintain the correct dosing interval (2 or 4 weeks). Patients should not take a double dose to make up for a missed one.

Safety Alerts

Xolair has a BOXED WARNING for Anaphylaxis. Anaphylaxis can occur after any dose of Xolair, even after one year or more of treatment. It may present as bronchospasm, hypotension, syncope, urticaria, and/or angioedema. Xolair should be administered in a healthcare setting equipped to manage life-threatening anaphylaxis. Patients should be observed for an appropriate period after administration.

Frequently Asked Questions (FAQ)

What if a patient's body weight is over 150 kg (330 lbs)?

Dosing for patients with a body weight greater than 150 kg has not been studied. The dosing tables do not provide recommendations for this population. Consult the full Prescribing Information.

What if the serum IgE level is below 30 IU/mL?

Xolair is not indicated for patients with pre-treatment IgE levels below 30 IU/mL. The calculator will indicate that the parameters are below the approved dosing range.

What if the serum IgE level is above 1500 IU/mL?

The use of Xolair has not been adequately studied in patients with IgE levels above 1500 IU/mL. Dosing recommendations are not available for this group.

Does the dose change if IgE levels fluctuate during treatment?

No. Dosing is based on the pre-treatment IgE level. Total IgE levels are often elevated during treatment and should not be used for dose determination or adjustments.

Why does the calculator sometimes refer to a "2-week" table?

For certain combinations of higher IgE and body weight, the 4-week dosing schedule is not appropriate. The dosing charts direct the user to a separate table for administration every 2 weeks.

Can a 300 mg dose be given as a single injection?

No. The maximum amount of Xolair that can be administered per injection site is 150 mg. Therefore, a 300 mg dose requires two separate 150 mg injections at different sites.

Is this calculator suitable for pediatric patients?

This calculator applies to patients aged 6 years and older for the moderate to severe persistent allergic asthma indication, consistent with the Prescribing Information.

Does this tool replace the official Prescribing Information?

No. This tool is for educational purposes only. It is critical to always consult the most current, official Prescribing Information before making any clinical decisions.