What precautions should be taken before and during rituximab therapy?

Precautions Taking Rituximab

All patients must be screened for hepatitis B virus (HBV) infection with HBsAg and anti-HBc testing before initiating rituximab, as rituximab carries a high risk of potentially fatal HBV reactivation. 1, 2

Mandatory Pre-Treatment Screening

Hepatitis B Screening (Critical)

• Screen ALL patients with HBsAg, anti-HBs, and anti-HBc before first dose 1, 2

• For HBsAg-positive patients:

  • If HBV DNA ≥2000 IU/mL and elevated ALT: Start antiviral treatment per AASLD guidelines
  • If HBV DNA <2000 IU/mL and normal ALT: Start antiviral prophylaxis 2-4 weeks before rituximab
  • Continue prophylaxis for at least 12 months after last rituximab dose (up to 24 months preferred) 1

• For HBsAg-negative/anti-HBc-positive patients:

  • Start antiviral prophylaxis - rituximab is classified as HIGH RISK for reactivation in this population 1, 3
  • Alternative: Monitor HBsAg, ALT, and HBV DNA every 3 months, but prophylaxis is strongly preferred
  • HBV reactivation can occur 1-2 years after last rituximab dose 1

Baseline Laboratory Testing

• Complete blood count (CBC) with differential and platelets before first dose 2
• Immunoglobulin levels (IgG, IgM, IgA) at baseline 4
  • Low IgG (<6 g/L) at baseline predicts serious infections
  • Monitor before each treatment cycle 4

Infection Risk Management

Progressive Multifocal Leukoencephalopathy (PML)

• Rituximab can cause fatal PML 2
• Educate patients to report new neurological symptoms immediately
• Discontinue rituximab if PML suspected

Vaccination Strategy

Timing is critical - rituximab profoundly impairs vaccine responses 5:

• Before rituximab initiation: Administer all indicated vaccines, especially:

  • Pneumococcal vaccines
  • Influenza vaccine
  • Other non-live vaccines as appropriate

• During rituximab therapy:

  • For influenza vaccine: Give on schedule (don't delay for seasonal reasons), then delay next rituximab dose by at least 2 weeks if disease activity allows 5
  • For other non-live vaccines: Time vaccination when next rituximab dose is due, then hold rituximab for at least 2 weeks after vaccination 5
  • Never give live vaccines during or after rituximab until B-cell recovery

Infusion-Related Reaction Prevention

Mandatory Premedication

• Acetaminophen and antihistamine before EVERY infusion 2
• Glucocorticoids strongly recommended:
  • Methylprednisolone 100 mg IV (or equivalent) 30 minutes before infusion 2
  • For RA/GPA/MPA: This is part of standard protocol
  • Alternative: Oral prednisone 40 mg can be effective 6

Infusion Rate Management

• First infusion: Start at 50 mg/hr, increase by 50 mg/hr every 30 minutes to maximum 400 mg/hr 2
• Subsequent infusions: Can start at 100 mg/hr if first infusion tolerated
• Have emergency medications immediately available (epinephrine, antihistamines, bronchodilators) 2

Ongoing Monitoring During Therapy

For Lymphoid Malignancies

• CBC with differential and platelets before each rituximab course during monotherapy 2
• With chemotherapy: CBC weekly to monthly, more frequently if cytopenias develop 2

For Rheumatic Diseases

• CBC with differential and platelets every 2-4 months 2
• Continue monitoring after final dose until resolution of cytopenias

Immunoglobulin Monitoring

• Measure IgG levels before each treatment cycle 4
• If IgG falls below 6 g/L: Serious infection risk increases significantly (21.3 per 100 person-years) 4
• Consider immunoglobulin replacement therapy if severe hypogammaglobulinemia develops 7
• Only 36% of patients normalize IgG after switching from rituximab 4

High-Risk Patient Populations

Increased serious infection risk with:

• Previous history of serious infection 4
• Baseline or treatment-emergent low IgG (<6 g/L) 4
• Higher corticosteroid doses 4
• Rituximab-associated neutropenia 4
• Chronic lung disease, diabetes, heart failure, cancer 4

Common Pitfall: Failing to recognize that hypogammaglobulinemia may unmask underlying common variable immunodeficiency (CVID), particularly in patients with autoimmune cytopenias 7. These patients require lifelong immunoglobulin replacement.

Cardiovascular Precautions

• Patients with significant cardiovascular disease should not receive accelerated 90-minute infusions 2
• Use standard infusion rates for these patients