About IVIG Administration

This section provides supplemental information related to the use of an IVIG dose calculator. Intravenous Immunoglobulin (IVIG) is a biologic therapy derived from pooled human plasma, containing a broad spectrum of antibodies. Dosing is highly individualized and based on patient weight, clinical indication, and institutional protocols. An accurate dosing and administration plan is critical for safety and efficacy.

Understanding the Outputs

A comprehensive IVIG calculation provides several key outputs for clinical use:

• Dosing Weight: The specific weight (Actual, Ideal, or Adjusted) used for the calculation, typically expressed in kilograms (kg).
• Total IVIG Dose: The complete amount of immunoglobulin to be administered for the treatment course, usually in grams (g).
• Daily Dose & Volume: The total dose divided by the number of administration days. The total volume is determined by the dose and the product’s concentration (e.g., 5% or 10%).
• Infusion Schedule: A detailed titration plan, starting with a slow initial rate and gradually increasing to a maximum rate to ensure patient tolerance. The schedule outlines the rate (mL/hr), duration, and volume for each step.

How to Use the Calculator Parameters

To ensure an accurate calculation, the following patient and product information is required:

• Patient Data: Weight and height are used to calculate body mass index (BMI) and determine the appropriate dosing weight. Patient sex is required for the Ideal Body Weight (IBW) formula, which differs between males and females.
• Dosing Weight Selection: Clinicians must choose the most appropriate weight metric. Actual Body Weight (ABW) is common, but for patients with obesity, Ideal (IBW) or Adjusted Body Weight (AdjBW) may be used to prevent overdosing based on excess adipose tissue.
• Dosing Regimen: This includes the prescribed dose (in g/kg or mg/kg) and the number of days over which the total dose will be administered. Selecting a pre-defined clinical indication (e.g., CIDP, ITP) often populates standard dosing parameters.
• Product Information: The specific IVIG product and its concentration (e.g., 10% solution) are needed to calculate the total volume for infusion.
• Infusion Rates: Parameters such as the initial rate, titration interval, rate increment, and maximum rate define the administration schedule and must align with the product’s prescribing information and institutional guidelines.

Dosing Overview

IVIG dosing varies significantly by indication. For primary immunodeficiency (PI), maintenance doses are typically 300-600 mg/kg every 3-4 weeks. For autoimmune and inflammatory conditions, higher induction doses of 1-2 g/kg are common, often divided over 2-5 days. For example, a 2 g/kg total dose for Guillain-Barré Syndrome (GBS) is typically administered as 0.4 g/kg daily for 5 consecutive days. Careful selection of dosing weight is crucial, as using actual body weight in obese patients can lead to unnecessarily large doses and increased risk of adverse events like thrombosis or renal impairment.

Switching Between Products

While the therapeutic dose in g/kg may remain the same, switching between different IVIG products requires careful attention. Products vary in their formulation, concentration, stabilizers, and recommended maximum infusion rates. A switch may necessitate a new infusion protocol and close monitoring during the first administration to ensure tolerability. Always consult the prescribing information for the new product before administration.

Handling a Missed Dose

If a patient misses a scheduled IVIG infusion, they should contact their healthcare provider for guidance. The provider will determine the best course of action based on the patient’s condition and the length of the delay. Patients should not attempt to self-adjust the dosing schedule or “double up” on a future dose without direct medical supervision.

Safety Alerts and Adverse Events

IVIG is generally well-tolerated, but adverse events can occur. Most are mild, transient, and infusion-related, such as headache, fever, chills, and myalgia. Slowing the infusion rate often mitigates these symptoms. More severe risks, although rare, include thromboembolic events, acute renal dysfunction, and aseptic meningitis. Pre-infusion hydration and careful patient screening for risk factors are essential safety measures.

Frequently Asked Questions (FAQ)

References

• U.S. Food and Drug Administration. (2017). Privigen [Prescribing Information]. Retrieved from www.fda.gov
• Takeda Pharmaceutical Company Limited. (2023). GAMMAGARD LIQUID [Immune Globulin Infusion (Human) 10%] for Healthcare Professionals. Retrieved from www.gammagard.com/hcp
• Pérez, E. E., Orange, J. S., & Bonilla, F. (2018). Update on the use of immunoglobulin in human disease: A review of evidence. Journal of Allergy and Clinical Immunology, 142(1), 35-52.e2.
• National Institute for Health and Care Excellence (NICE). (2018). Intravenous immunoglobulin use in the NHS: quality standard [QS138]. Retrieved from www.nice.org.uk