RILAST 100

Indications

• Non-Hodgkin's lymphoma (specialist use only)
• Chronic lymphocytic leukaemia (specialist use only)
• Rheumatoid arthritis (specialist use only)
• Granulomatosis with polyangiitis and microscopic polyangiitis (specialist use only)

Dosage

Children: Refer to BNF for Children for specific paediatric dosing information related to indicated conditions

Adults: By intravenous infusion: 1 g, then 1 g after 2 weeks. Consult product literature for information on retreatment.

Mechanism of action

Rituximab binds specifically to the CD20 antigen on B cells, leading to their destruction through various mechanisms including complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, and induction of apoptosis. This results in a reduction of B cell populations, which is beneficial in conditions where B cells are pathologically active, such as in certain malignancies and autoimmune diseases.

Pharmacodynamics

The pharmacodynamics of rituximab involve the modulation of B cell activity and reduction in B cell counts. The drug's action leads to decreased levels of immunoglobulins and altered immune responses, which can be advantageous in treating autoimmune conditions. However, this immunosuppressive effect also increases the risk of infections, particularly during treatment and for some time after cessation, due to the depletion of B lymphocytes.

Pharmacokinetics

Rituximab exhibits a monoclonal antibody pharmacokinetic profile, characterized by a long half-life, which allows for less frequent dosing schedules. The drug is primarily eliminated through the reticuloendothelial system. After intravenous administration, peak serum concentrations are reached approximately 3 to 6 hours post-infusion. The clearance of rituximab can be influenced by factors such as the presence of anti-drug antibodies, body weight, and the presence of disease.

Contra-indications

• Severe infection
• Progressive multifocal leucoencephalopathy
• Severe heart failure
• Uncontrolled heart disease
• Active hepatitis B infection

Adverse effects

• Angioedema
• Anxiety
• Decreased appetite
• Arrhythmias
• Bone marrow disorders
• Bursitis
• Cancer pain
• Cardiac disorders
• Chest pain
• Chills
• Dizziness
• Fatigue
• Fever
• Headaches
• Hypertension
• Hypotension
• Insomnia
• Nausea
• Oedema
• Skin reactions
• Throat irritation
• Tinnitus
• Tumour lysis syndrome
• Vision changes

Interactions

• Filgotinib (increases risk of immunosuppression)

Precautions

• Monitor for cognitive, neurological, or psychiatric signs
• Effective contraception required during and for 12 months post-treatment
• Pre-medication recommended to minimise adverse reactions
• Patients with positive hepatitis B serology should be monitored closely

Pregnancy

Avoid unless potential benefit to mother outweighs risk of B-lymphocyte depletion in fetus.

Breast-feeding

Avoid breastfeeding during and for 12 months after treatment.

Storage

Store in a refrigerator at 2 to 8 degrees Celsius. Protect from light.

Formulations

• Solution for infusion 100 mg/10 ml
• Concentrate for solution for infusion 500 mg/50 ml