Home Drug Guide Rituximab

Drug Guide

Generic Name

Rituximab

Brand Names Rituxan

Classification

Therapeutic: Antineoplastic and Immunomodulating Agent

Pharmacological: Monoclonal Antibody

FDA Approved Indications

Non-Hodgkin's lymphoma
Chronic lymphocytic leukemia
Rheumatoid arthritis (with methotrexate)
Granulomatosis with polyangiitis (GPA)
Microscopic polyangiitis

Mechanism of Action

Rituximab is a chimeric monoclonal antibody targeting CD20 antigen on B-cells, leading to B-cell depletion via complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, and apoptosis.

Dosage and Administration

Adult: Varies based on indication; typically 375 mg/m² weekly for 4 weeks for lymphoma, 1000 mg on days 1 and 15 for rheumatoid arthritis.

Pediatric: Use in pediatric populations is limited and based on specific indications and protocols.

Geriatric: No specific dosage adjustments, but monitor for increased risk of adverse effects in older adults.

Renal Impairment: No specific dose adjustment required.

Hepatic Impairment: Limited data; use with caution.

Pharmacokinetics

Absorption: Administered IV; bioavailability not applicable.

Distribution: Widely distributed in the body, including B-cells in lymphoid tissues.

Metabolism: Degraded via proteolytic catabolism into peptides and amino acids.

Excretion: Cleared through reticuloendothelial system; not primarily renal.

Half Life: Approximately 3-4 days, varies with dose and treatment schedule.

Contraindications

Hypersensitivity to Rituximab or its components.

Precautions

Increased risk of infections, including reactivation of hepatitis B and progressive multifocal leukoencephalopathy (PML).
Monitor for infusion reactions, especially during the first infusion.

Adverse Reactions - Common

Infusion reactions (fever, chills, rigors, hypotension) (Common)
Upper respiratory tract infections (Common)
Fatigue, nausea, cough (Common)

Adverse Reactions - Serious

Severe infusion reactions, including bronchospasm, hypotension, angioedema (Uncommon)
PML, a fatal brain infection (Rare)
Severe neutropenia, thrombocytopenia, or anemia (Uncommon)
Hepatitis B reactivation (Rare)

Drug-Drug Interactions

Other immunosuppressants, vaccines (live), other biologics

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for infusion reactions, infections, CBC counts, liver function tests.

Diagnoses:

Risk for infection related to immunosuppression.
Risk for allergic reaction related to infusion.

Implementation: Pre-medicate with acetaminophen, antihistamines, and corticosteroids to reduce infusion reactions.

Evaluation: Assess for signs of infection, review blood counts, monitor infusion site reactions.

Patient/Family Teaching

Report any signs of infection immediately.
Understand the importance of follow-up blood tests.
Be aware of potential infusion reactions and how they are managed.

Special Considerations

Black Box Warnings:

Progressive multifocal leukoencephalopathy (PML), a rare brain infection, can be fatal.
Hepatitis B reactivation, which can be severe or fatal.

Genetic Factors: Screen for hepatitis B surface antigen and core antibody before initiating therapy.

Lab Test Interference: May cause falsely low values in certain immunoassays.

Overdose Management

Signs/Symptoms: Unknown, but potential for severe infusion reactions or immune suppression.

Treatment: Supportive care; no specific antidote.

Storage and Handling

Storage: Refrigerate between 2°C and 8°C, protected from light.

Stability: Stable until expiration date when stored properly.