Rituximab in the Intensive Care Unit: A Review of Indications and Clinical Considerations.

Rituximab, a chimeric monoclonal antibody targeting CD20 on B cells, has become an important therapeutic agent in the intensive care unit (ICU) for a range of immune-mediated conditions. This review explores the current indications, pharmacological rationale, and practical considerations for rituximab use in the ICU. Key indications include autoimmune haemolytic anaemia, thrombotic thrombocytopenic purpura, haemophagocytic lymphohistiocytosis, autoimmune encephalitis, myasthenia gravis, and ANCA-associated vasculitis. In these conditions, rituximab often serves as a second-line or salvage therapy, particularly when corticosteroids or conventional treatments fail. Its role in respiratory failure related to inflammatory myopathies, such as anti-synthetase and anti-MDA-5 syndromes, is emerging. While generally well-tolerated, rituximab carries risks of infusion reactions, infectious complications, hematologic toxicity, and rare organ-specific adverse events. Given the increasing use of rituximab across diverse critically ill populations, intensivists must be familiar with its indications, benefits, and risks to optimize patient outcomes.