Contraindications and Precautions for Rituximab (Rituxan)
Rituximab has no absolute contraindications according to the FDA label, but several important precautions and relative contraindications should be considered before administration to minimize morbidity and mortality risks. 1
Key Precautions and Relative Contraindications
Infection-Related Concerns
- Hepatitis B screening is mandatory before initiating therapy due to risk of reactivation of occult hepatitis B infection 2
- Consider avoiding rituximab in patients scheduled for SARS-CoV-2 vaccination due to potential reduced vaccine efficacy 2
- Withhold treatment in patients with active infections until resolved 1
- Use with caution in patients requiring intensive immunosuppression, especially when combined with other immunosuppressants like antithymocyte globulin 3
Infusion-Related Reactions
- Higher risk patients for severe infusion reactions include those with:
- Pre-existing cardiac or pulmonary conditions
- Prior cardiopulmonary adverse reactions
- High numbers of circulating malignant cells 2
- Severe reactions can include pulmonary infiltrates, acute respiratory distress syndrome, myocardial infarction, ventricular fibrillation, and cardiogenic shock 2
Specific Clinical Scenarios
- Severe renal disease: Comparability with cyclophosphamide not proven; consider plasma exchange instead 2
- Mechanical ventilation for alveolar hemorrhage: Rituximab may not be appropriate 2
- Hypogammaglobulinemia: Monitor immunoglobulin levels, especially with repeated courses 2
- Pediatric patients: Higher risk of serum sickness and infusion-related reactions (47% with first dose) 2
Monitoring Requirements
Before Treatment
- Complete hepatitis B screening (HBsAg, anti-HBc)
- Baseline B-cell counts and immunoglobulin levels
- Cardiac and pulmonary function assessment in high-risk patients
During Treatment
- Close monitoring during infusions, particularly first 2 hours of initial infusion
- Vital signs monitoring
- For severe reactions: discontinue infusion immediately and provide supportive care 2
After Treatment
- Regular monitoring of B-cell counts and immunoglobulin levels, especially with repeated courses 2
- Heightened vigilance for infections for at least 6 months after treatment
Important Adverse Effects to Monitor
- Tumor lysis syndrome: Requires aggressive IV hydration and anti-hyperuricemic agents 1
- Cardiac adverse reactions: Can be severe and potentially fatal 1
- Renal toxicity: Discontinue if rising serum creatinine or oliguria develops 1
- Bowel obstruction/perforation: Evaluate abdominal pain or vomiting 1
Special Considerations
- CD19 and CD20 expression: Rituximab targets CD20 (not CD19), though both are B-cell markers. Higher pretreatment CD19/CD20 levels may correlate with increased infection risk 3, 4
- Immunoglobulin levels: Higher IgG concentrations may affect rituximab clearance, potentially reducing efficacy 4
- B-cell monitoring: Repopulation of CD19+ B cells, particularly transitional and memory B cells, may predict clinical relapse approximately 4 months in advance 5, 6
Rituximab therapy should be administered only by healthcare professionals with appropriate medical support to manage potentially fatal infusion-related reactions 1. The benefit-risk assessment should be carefully considered in each patient, with particular attention to infection risk in those requiring combination immunosuppressive therapy.