Which of the following is a commonly observed adverse reaction that occurs during a rituximab infusion?

• A. Mucositis
• B. Angioedema
• C. Rigors
• D. Renal toxicity

Answer: (C)

Rituximab infusions frequently trigger infusion-related reactions, especially during the first exposure. The classic sign is rigors—shaking chills with possible fever—as cytokines are released when the antibody binds CD20 on B cells. Because this reaction is so common with rituximab, clinicians premedicate with acetaminophen and an antihistamine and often start at a slower infusion rate to prevent or lessen symptoms; if rigors occur, the infusion can be paused or slowed and symptoms treated, with steroids used for more severe cases. Mucositis is a direct cytotoxic chemotherapy effect rather than an immediate infusion reaction. Angioedema can occur with hypersensitivity but is not as typical for rituximab as rigors. Renal toxicity is not a common acute infusion reaction for rituximab and is more linked to other agents. So rigors best represent the commonly observed adverse reaction during a rituximab infusion.