IVIg Dosing Guide | IVIGdosing.com

Philosophy of IVIg Stewardship

Immunoglobulin (Ig) is a precious biological resource derived from the pooled plasma of thousands of donors. It is not a synthesized drug; its supply is finite and dependent on human donation.

Key Principles

Utilization Management: Prescribing should be evidence-based.
Lowest Effective Dose: Tapering should be attempted for maintenance.
Review: Regular clinical reassessment is mandatory.

Economic Impact & Global Usage

IVIg is consistently one of the top pharmaceutical expenditures for Canadian hospitals. A single course of treatment can cost between $5,000 and $20,000+ CAD depending on the dose and weight of the patient.

Usage Trends

🇨🇦 Canada: Among the highest per capita usage in the world.
🇺🇸 USA: Very high usage; commercial model drives prescribing.
🇪🇺 Europe: Stricter stewardship and lower per capita usage.

Supply Chain

Canada is not self-sufficient in plasma. We rely heavily on the global plasma market (primarily the US) for finished Ig products. This makes stewardship a matter of national health security.

Risks & Transfusion Reactions

Common Side Effects

Headache

Mechanism: Vasospasm or sterile inflammation of the meninges due to cytokine release or stabilizing agents.

Fever / Chills / Myalgia

Mechanism: Release of inflammatory cytokines (like IL-6 and TNF-alpha) triggered by IgG aggregates or antigen-antibody complex formation.

Fatigue / Nausea

Mechanism: General systemic inflammatory response and transient fluid/osmotic shifts affecting the central nervous system.

Rare & Serious Side Effects

Anaphylaxis (The IgA Trap)

Mechanism: In IgA-deficient patients with anti-IgA antibodies, the trace IgA in IVIg is recognized as a foreign antigen, triggering massive mast cell degranulation.

Aseptic Meningitis

Mechanism: Direct irritation of the meninges by high-dose IgG or stabilizers, leading to a hypersensitivity reaction within the CNS (sterile inflammation). Patients get a terrible headache, neck stiffness, and photophobia 24–48 hours later.

Hemolysis

Mechanism: Passive transfer of donor anti-A or anti-B isoagglutinins (antibodies) which coat the recipient's red blood cells, leading to complement activation and destruction (hemolysis). Positive DAT.

Thrombosis (Stroke/PE/DVT)

Mechanism: Increased plasma viscosity from high protein load and potential activation of coagulation factor XIa present in some preparations.

Renal Impairment

Mechanism: "Osmotic nephrosis" caused by stabilizers (historically sucrose) entering renal proximal tubule cells, causing them to swell and obstruct function.

TRALI

Mechanism: Donor anti-leukocyte antibodies activate recipient neutrophils in the pulmonary microvasculature, causing capillary leak and pulmonary edema.

Patient Counseling Checklist

1

Blood Product Consent

Inform the patient that IVIg is a human blood product. Discuss the (very low) theoretical risks of transfusion-transmitted infections.

2

Hydration

Emphasize the importance of being well-hydrated before and during the infusion to reduce renal and thrombotic risks and minimize headaches.

3

Symptom Reporting

Instruct patient to report immediately: Shortness of breath, chest pain, severe headache, leg swelling, or decreased urine output.

4

Vaccination Timing

IVIg can interfere with live vaccines (MMR, Varicella) for 3-11 months. Consult the immunization guide.

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