What is the recommended dosage and administration protocol for Intravenous Immunoglobulin (IVIG) in patients, considering their individual medical history and clinical presentation?

IVIG Administration: Dosing and Protocol

For most clinical indications, administer IVIG at 2 g/kg total dose, either as a single infusion or divided over 2 consecutive days, with the divided approach preferred in patients at risk for fluid overload. 1

Dosing by Clinical Indication

Immune Thrombocytopenic Purpura (ITP)

• Administer 1 g/kg as a single one-time dose, which may be repeated if necessary 2, 1, 3
• This has largely replaced the older 0.4 g/kg/day for 5 days regimen due to convenience and similar efficacy 2, 3
• Response occurs rapidly, with many patients responding within 24 hours and peak response at 2-4 days 2, 3
• Effect is typically transient, with platelet counts returning to baseline within 2-4 weeks 2, 3
• For grade 2 immune checkpoint inhibitor-related thrombocytopenia, use IVIG in conjunction with corticosteroids when rapid platelet increase is required 2
• For grade 3-4 toxicity, initial dose is 1 g/kg as one-time dose, repeatable if necessary 2

Cardiac Transplant Antibody-Mediated Rejection

• Use 2 g/kg divided over days 1 and 30 (first day after completion of rabbit anti-thymocyte globulin) 2
• Alternative protocol: 2 g/kg divided into 2 doses over 2 consecutive days on days 1-2 and days 29-30, not to exceed 140 g total 2
• Combine with plasmapheresis, steroids, and rituximab for hemodynamically compromised patients 2

Kawasaki Disease

• Administer 2 g/kg as a single infusion 2, 1
• This is the standard of care with an 11-month interval before measles-containing vaccines 2

Guillain-Barré Syndrome

• Administer 0.4 g/kg/day for 5 consecutive days 1
• Requires inpatient monitoring with ICU capability for severe cases 1

Immunodeficiency Replacement Therapy

• Initial dose: 300-400 mg/kg IV monthly 1, 4
• May increase to 0.3 g/kg every 2-3 weeks if inadequate response 1, 4
• For Common Variable Immunodeficiency (CVID), use 0.3-0.4 g/kg every 3-4 weeks after initial high-dose treatment 1

Myasthenia Gravis and Immune Checkpoint Inhibitor Neurologic Toxicity

• For grade 3-4 toxicity: 2 g/kg IV over 5 days with permanent discontinuation of checkpoint inhibitor 1

Idiopathic Inflammatory Myopathies

• Administer 1-2 g/kg over 2 consecutive days 1

Multisystem Inflammatory Syndrome in Children (MIS-C)

• Administer 2 g/kg based on ideal body weight 1

Pre-Administration Requirements

Mandatory Laboratory Assessment

• Check serum IgA level before first IVIG administration to identify patients at risk for severe anaphylaxis 1
• Use IgA-depleted IVIG preparations if deficiency is detected 1
• Evaluate renal function including serum creatinine and urine output 1
• Assess thrombotic risk factors 1
• Review cardiac function, especially in patients with cardiac dysfunction or fluid overload risk 1
• Document history of previous infusion reactions 1

Critical Contraindication

• IVIG is contraindicated in patients with selective IgA deficiency and detectable IgA antibodies due to risk of anaphylaxis 4

Premedication Protocol

• Administer diphenhydramine and acetaminophen as standard premedication 1, 3
• Consider corticosteroids (e.g., 20 mg prednisone) for patients with history of infusion reactions 2, 1
• For IV anti-D (alternative to IVIG in ITP), premedication with paracetamol/acetaminophen or corticosteroids is recommended to reduce fever/chills, especially with higher doses 2

Weight-Based Dosing Adjustments

• For obese patients, use ideal body weight or adjusted body weight instead of actual body weight to prevent excessive dosing 1
• For patients with cardiac dysfunction, divide total dose over 2 days to minimize fluid overload 1

Administration and Monitoring

• Administer infusion over several hours to reduce toxicity 1
• Monitor renal function including urine output and serum creatinine during infusion 1
• Initial infusions in immunodeficient patients not treated in previous 8 weeks require cautious administration due to risk of complement-mediated adverse reactions 4

Adverse Effects Profile

Common (Frequent but Usually Mild)

• Headaches (often moderate but sometimes severe) 2, 3
• Fever, chills, fatigue 2
• Nausea, diarrhea 2
• Blood pressure changes and tachycardia 2
• Flushing 2

Serious but Rare

• Renal insufficiency and renal failure 2, 3
• Thrombosis 2, 3
• Aseptic meningitis 2
• Transient neutropenia 2, 3
• Anaphylactoid reactions (especially in IgA-deficient patients) 2

Critical Timing Considerations

• Do not perform plasmapheresis immediately after IVIG administration, as it will remove the immunoglobulin 1
• In cardiac transplant protocols, IVIG is given immediately after plasmapheresis, not before 2
• Allow appropriate intervals before administering measles- or varicella-containing vaccines: 8 months for 300-400 mg/kg replacement therapy, 10 months for 1000 mg/kg ITP treatment, 11 months for 2 g/kg Kawasaki disease treatment 2

Special Populations

Pregnancy

• IVIG (1 g/kg) is safe and recommended for pregnant patients with ITP 3
• Considered first-line option along with corticosteroids 3

Emergency/Life-Threatening Bleeding

• Combine IVIG (1 g/kg) with high-dose corticosteroids for rapid platelet elevation 3
• Consider adding platelet transfusions for life-threatening bleeding 3

Common Pitfalls to Avoid

• Avoid using actual body weight in obese patients—this leads to excessive dosing and increased adverse effects 1
• Do not skip IgA level testing before first administration—anaphylaxis risk is real and preventable 1, 4
• Do not administer full dose as single infusion in cardiac patients—divide over 2 days to prevent volume overload 1
• Do not expect sustained response in ITP—effect is transient (2-4 weeks) and patients should be counseled accordingly 2, 3
• Recognize that IVIG is a pooled blood product—inform patients of theoretical infectious disease transmission risk, though modern processing has minimized this 3