What is the primary toxicity to monitor for with rituximab during the first dose?

Rituximab, a monoclonal antibody targeting CD20 on B lymphocytes, is known to pose a risk for hypersensitivity reactions, particularly during the first infusion. These reactions can range from mild symptoms like fever and chills to more severe reactions such as anaphylaxis. This is primarily due to the infusion-related cytokine release that can occur, leading to symptoms that may be mistaken for an allergic response.

Monitoring for hypersensitivity during the first dose of rituximab is crucial. It reflects the need for careful observation, as reactions often occur within the first 30 to 120 minutes of the infusion. Prophylactic measures such as premedication with antihistamines and corticosteroids are commonly implemented to mitigate these risks.

While hepatotoxicity, neutropenia, and nausea and vomiting can occur with rituximab, they are not the primary concerns associated with the initiation of therapy. Neutropenia is a potential long-term effect related to rituximab but does not present as an immediate reaction during the first infusion. Similarly, nausea and vomiting are more commonly associated with chemotherapy agents rather than rituximab. Therefore, hypersensitivity reaction stands out as the main focus during the administration of the initial dose