About This Calculator
The Fasenra (benralizumab) Dosing Calculator is an educational resource designed for healthcare professionals to project dosing schedules based on official prescribing information. It helps determine administration dates for both treatment initiation and ongoing maintenance therapy in eligible patients with severe eosinophilic asthma.
Outputs
After entering the required patient data, the calculator provides the following outputs:
- Recommended Dose: Displays the calculated dose in milligrams (mg), which is 30 mg for adults and adolescents, and either 10 mg or 30 mg for children aged 6 to 11 based on body weight.
- Dosing Schedule: For new patients, it generates a projected timeline for the first several doses, including the initial three loading doses and subsequent maintenance doses.
- Next Dose Date: For existing patients on maintenance therapy, it calculates the date of the next scheduled dose based on the date of their last administration.
- Patient Summary: Key patient details used for the calculation, such as age and weight (if applicable), are summarized for quick verification.
How to Use
To use the calculator, follow these steps:
- Select Patient Status: Choose "New Patient" for those initiating therapy or "Existing Patient" for those already on the 8-week maintenance schedule.
- Enter Patient Age: Input the patient's age in years. This is crucial as dosing recommendations differ for pediatric patients.
- Enter Patient Weight (if prompted): The weight field appears for patients aged 6 to 11. Enter the weight and select the appropriate unit (kg or lbs). Weight is required to determine the correct dose (10 mg or 30 mg) in this age group.
- Select Date:
- For a New Patient, select the intended Treatment Start Date.
- For an Existing Patient, select the Date of Last Administered Dose.
- Calculate Schedule: Click the "Calculate Schedule" button to generate the dosing information.
Dosing Overview
Fasenra is administered as a subcutaneous injection. The recommended dosing regimen is as follows:
Adults and Adolescents (aged 12 years and older)
The recommended dose is 30 mg administered once every 4 weeks for the first 3 doses, followed by once every 8 weeks thereafter.
Pediatric Patients (aged 6 to 11 years)
The recommended dose is based on body weight:
- For patients who weigh less than 35 kg: 10 mg
- For patients who weigh 35 kg or more: 30 mg
Similar to adults, the dose is administered once every 4 weeks for the first 3 doses, followed by once every 8 weeks thereafter.
Switching Therapies
There is no specific guidance in the prescribing information on switching from other biologics (e.g., mepolizumab, reslizumab, dupilumab, or tezepelumab) to Fasenra. The decision to switch should be based on a comprehensive clinical evaluation by a qualified healthcare professional. Generally, the initiation of Fasenra would follow the standard "New Patient" dosing schedule.
Missed Dose
If a maintenance dose is missed, it should be administered as soon as possible. The subsequent dose should be given on the patient's regularly scheduled date. This calculator's "Missed Dose" function provides this standard guidance from the prescribing information. Patients should not administer a double dose to compensate for a missed one.
Safety Alerts
This information is not exhaustive. Always consult the full Prescribing Information before administration.
- Hypersensitivity Reactions: Serious reactions, including anaphylaxis, have occurred. These can occur within hours of administration but may have a delayed onset. Discontinue Fasenra in the event of a hypersensitivity reaction.
- Acute Asthma Symptoms: Fasenra should not be used to treat acute asthma symptoms or acute exacerbations.
- Parasitic (Helminth) Infection: It is unknown if benralizumab influences the response against helminth infections. Treat patients with pre-existing infections before starting Fasenra.
Frequently Asked Questions
For patients aged 6 to 11 years, the Fasenra dose is weight-dependent. The prescribing information specifies a 10 mg dose for those under 35 kg and a 30 mg dose for those 35 kg and above. For patients aged 12 and older, the standard dose is 30 mg regardless of body weight.
A "New Patient" is one who is starting Fasenra for the first time. The calculator will project the initial loading dose schedule (first three doses at 4-week intervals) followed by the maintenance schedule (every 8 weeks). An "Existing Patient" is someone already on the 8-week maintenance schedule, and the calculator will simply determine the next due date.
The calculator is designed to project future appointment dates. If you enter a start date in the past for a new patient, it will still calculate the schedule from that date. The tool may show a confirmation prompt to ensure this was intentional, as it's useful for retrospectively mapping a patient's schedule.
No. According to the prescribing information, no dose adjustments are necessary for patients with renal or hepatic impairment. This calculator follows the standard dosing guidelines and does not account for specific comorbidities.
This option does not calculate a new date. Instead, it displays the official guidance for a missed dose: "If a dose is missed, administer the dose as soon as possible. Thereafter, resume dosing on the regularly scheduled date." It serves as a quick reference for this common clinical question.
The loading dose period consists of the first three doses. The first dose is given on day 0, the second dose at week 4, and the third dose at week 8. After the third dose, the patient transitions to the maintenance schedule of one dose every 8 weeks.
Yes, Fasenra can be administered by a healthcare professional or self-administered by the patient or caregiver after training. It is available in a pre-filled syringe or an autoinjector (Fasenra Pen) for subcutaneous injection.
All dosing logic and schedules are based on the official FDA Prescribing Information for Fasenra (benralizumab). The tool is intended to reflect this guidance accurately, but users should always verify with the most current version of the official drug label.
References
- FASENRA® (benralizumab) injection, for subcutaneous use. Prescribing Information. AstraZeneca; 2019.
- Fasenra HCP Official Website. AstraZeneca.
- Fasenra (benralizumab) European Public Assessment Report (EPAR). European Medicines Agency.
- Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2023.
