What is the structure/class of IVIG?
• Pooled human immunoglobulin G (IgG) antibodies from plasma donors
• Contains trace IgA and stabilizers
• Provides passive immunity [expanded for LO1]
How is IVIG administered and absorbed?
• Intravenous infusion; some subcutaneous formulations exist
• 100% bioavailability via IV route
• Peak plasma levels achieved immediately [expanded for LO1]
What is the biological half-life and bioavailability of IVIG?
• Half-life ~18–32 days
• Bioavailability 100% (IV)
• Distributed in intravascular and extravascular compartments [expanded for LO1]
How is IVIG metabolised and excreted?
• Catabolised by the reticuloendothelial system
• Degraded to amino acids and peptides; renal excretion minimal [expanded for LO1]
What is the mechanism of action of IVIG?
• Neutralises autoantibodies
• Modulates Fc receptors on macrophages
• Inhibits complement deposition
• Suppresses cytokine production
• Enhances regulatory T-cell activity [expanded for LO1]
What is the simplified mechanism of IVIG?
• Blocks pathogenic antibodies and downregulates inflammation [expanded for LO1]
What are the clinical indications for IVIG?
• Immunobullous diseases (PV, BP, MMP, EBA)
• TEN, SJS
• Kawasaki disease
• Dermatomyositis, Scleromyxoedema
• Immune deficiency syndromes [expanded for LO1]
What are the contraindications for IVIG?
- Hypersensitivity to IVIG or excipients (e.g. sucrose)
- IgA deficiency with anti-IgA antibodies
- Caution in renal failure, hyperviscosity, cardiac failure
o Rheumatoid factor, cryoglobulins (increased risk of acute renal failure)
o religious beliefs
[expanded for LO1]
What are the adverse effects of IVIG?
• Common: headache, flushing, fever, chills, fatigue
• Serious: aseptic meningitis, renal failure, thrombosis, haemolysis, anaphylaxis
• Delayed: neutropenia, hepatitis [expanded for LO1]
What are important drug interactions for IVIG?
• Reduces efficacy of live vaccines for ~3–6 months
• Additive nephrotoxicity with other nephrotoxic agents [expanded for LO1]
What is the dosing of IVIG?
• 2 g/kg total over 2–5 days for most dermatoses (PV, BP, TEN)
• 400 mg/kg/day for 5 days (Kawasaki)
• 1–2 g/kg monthly for immunomodulation [expanded for LO1]
What is the safety in pregnancy and lactation for IVIG?
• Considered safe in pregnancy and lactation
• Used in autoimmune and alloimmune disorders (e.g. ITP, APS) [expanded for LO1]
What investigations are needed before IVIG?
• FBC, UEC, LFT, serum IgA
• Baseline urine dipstick (protein/haematuria)
• Viral serology (Hep B/C, HIV)
• Consider thrombosis risk and hydration status [expanded for LO1]
How should IVIG be monitored?
• Monitor vitals during infusion
• Observe for anaphylaxis or infusion reaction
• Check UEC, LFT if prolonged therapy
• Repeat serology and renal function periodically [expanded for LO1]
What are clinical pearls for IVIG use?
• Infuse slowly to reduce adverse reactions
• Ensure adequate hydration to avoid renal injury
• Safe in pregnancy, limited immunosuppression
• Compared with plasmapheresis, less invasive but costlier
• Compared with rituximab, acts faster but shorter duration of effect [expanded for LO1]
