Generic Name

Rituximab-arrx

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Classification

FDA Approved Indications

• Non-Hodgkin lymphoma
• Chronic lymphocytic leukemia
• Rheumatoid arthritis (in combination with methotrexate)
• Granulomatosis with polyangiitis
• Microscopic polyangiitis

Mechanism of Action

Rituximab-arrx is a chimeric monoclonal antibody that targets CD20, a surface antigen found on B lymphocytes. It destroys B cells through multiple mechanisms including antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and induction of apoptosis, leading to depletion of circulating B cells.

Dosage and Administration

Adult: Dosage varies depending on indication; typically, 375 mg/m2 weekly for 4 weeks for lymphomas, with adjustments as per specific protocols.

Pediatric: Used in specific indications; dosing based on body surface area or weight, according to clinical guidelines.

Geriatric: No specific dose adjustments solely based on age, but renal and hepatic function should be considered.

Renal Impairment: No specific adjustments; monitor closely.

Hepatic Impairment: No specific adjustments; monitor closely.

Pharmacokinetics

Absorption: Administered intravenously; bioavailability is 100% via IV route.

Distribution: Distributed primarily in the blood and lymphoid tissues.

Metabolism: Metabolized via catabolic pathways like other IgG antibodies.

Excretion: Excreted via protein catabolism; not eliminated via urine or feces significantly.

Half Life: Approximately 19-22 days in adults; varies with dose and patient factors.

Contraindications

• Hypersensitivity to rituximab or any component of the formulation

Precautions

• Increased risk of infections due to immune suppression; hepatitis B reactivation; infusion reactions; progressive multifocal leukoencephalopathy (PML)

Adverse Reactions - Common

• Infusion reactions (fever, chills, hypotension) (Common)
• Infections (upper respiratory, urinary tract) (Common)
• Nausea, fatigue, headache (Common)

Adverse Reactions - Serious

• Severe infusion reactions including anaphylaxis (Rare)
• Progressive multifocal leukoencephalopathy (PML) (Very rare)
• Severe infections, including opportunistic infections (Rare)
• Hematologic toxicities, such as thrombocytopenia or leukopenia (Uncommon)

Drug-Drug Interactions

• Other immunosuppressants, live vaccines, anthracyclines

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Report fever, chills, rash, or difficulty breathing immediately.
• Use effective contraception during and for 12 months after treatment.
• Avoid live vaccines during therapy and for at least 6 months afterward.
• Stay hydrated and report signs of infections or infusion reactions.

Special Considerations

Black Box Warnings:

• Fatal infusion reactions, PML, severe mucocutaneous reactions, hepatitis B reactivation, tumor lysis syndrome

Genetic Factors: Testing for hepatitis B virus before initiation recommended.

Lab Test Interference: May cause false elevations in serum immunoglobulin levels and impact serology tests.

Overdose Management

Signs/Symptoms: Hypersensitivity, severe infusion reactions, blood dyscrasias.

Treatment: Supportive care; discontinuation of infusion; monitor vital signs and provide symptomatic treatment as needed.

Storage and Handling

Storage: Store refrigerated at 2°C to 8°C (36°F to 46°F). Protect from light.

Stability: Use within the specified period as per manufacturer instructions; discard unused portion.