Makindo Medical Notes

💉 Rituximab is a chimeric monoclonal antibody targeting CD20 on B lymphocytes. ⚠️ Rare but serious risks include progressive multifocal leukoencephalopathy (PML), reported in patients with autoimmune disease (e.g., SLE). Resuscitation equipment must always be available during administration.

📖 About

• Targets CD20+ B cells → depletion of circulating and tissue B lymphocytes.
• Used in both haematological malignancies and autoimmune diseases.
• Check BNF here for current prescribing guidance.

⚙️ Mechanism of Action

• Monoclonal antibody binding to CD20 antigen on B cells.
• Causes complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity → B cell apoptosis and depletion.
• Reduces autoantibody production in autoimmune disease.

🎯 Indications

• Haematology: recurrent or refractory follicular lymphoma, aggressive B cell NHL, diffuse large B cell lymphoma.
• Rheumatology/Immunology: Rheumatoid arthritis, SLE, Sjögren’s syndrome, antiphospholipid syndrome, dermatomyositis, ITP.
• Neurology: CIDP (chronic inflammatory demyelinating polyneuropathy), some cases with paraproteinaemia.

⛔ Contraindications

• Active or severe uncontrolled infections.
• Severe immunosuppression.

⚠️ Side Effects

• Infusion reactions (cytokine release: fever, rigors, dyspnoea, hypotension). Premedicate with steroids + antihistamines.
• Cardiac complications: can exacerbate angina or ischaemia.
• Type III hypersensitivity reactions (immune complex–mediated).
• Bone marrow suppression → pancytopenia, infection risk.
• PML (progressive multifocal leukoencephalopathy): rare, often fatal JC virus reactivation.
• Other: tumour lysis syndrome, ARDS, transient hypotension, nausea/vomiting.

💊 Dose & Administration (check BNF/local policy)

• IV infusion, dose varies by indication (e.g., 375 mg/m² weekly x 4 for lymphoma; 1 g IV on days 1 & 15 for RA).
• Administer slowly, with gradual rate escalation.
• Withhold antihypertensives 12 h before infusion to avoid severe hypotension.
• Resuscitation equipment must be immediately available.

💡 Clinical Pearls

• Monitor CBC regularly → risk of cytopenias.
• Screen for hepatitis B before treatment → risk of reactivation.
• Always premedicate with steroid + antihistamine to reduce infusion reactions.
• Warn patients about the very rare but fatal risk of PML; new neurological symptoms warrant urgent evaluation.

📚 References

• BNF: Rituximab
• ACR Case Report on Rituximab & PML