What is the recommended management for rigors (fever and shaking) that develop during a rituximab infusion in a patient being treated for hairy‑cell leukemia?

Management of Rituximab-Induced Rigors

For rigors (fever and shaking) during rituximab infusion, immediately stop or slow the infusion rate, provide symptomatic treatment with antipyretics and antihistamines, and once symptoms resolve, resume the infusion at half the previous rate. 1

Immediate Management Algorithm

Grade 1/2 Reactions (Mild to Moderate Rigors)

• Stop or significantly slow the infusion rate immediately when rigors develop 1
• Administer symptomatic treatment:
  • Acetaminophen (paracetamol) 650-1000 mg orally
  • Diphenhydramine 25-50 mg IV or orally
  • Consider meperidine specifically for severe chills and rigors 1
• Resume infusion once patient is stable at half the previous infusion rate, then titrate upward to tolerance 1
• Continue close monitoring throughout remainder of infusion

Grade 3/4 Reactions (Severe Rigors with Hemodynamic Instability)

• Stop the infusion completely 1
• Aggressive symptomatic treatment:
  • IV corticosteroids (methylprednisolone 100 mg or equivalent)
  • Epinephrine if anaphylactoid features present
  • Bronchodilators if bronchospasm develops
  • Oxygen and hemodynamic support as needed 2
• After complete resolution of symptoms, treatment can be resumed at half the previous rate, unless the reaction was severe enough to warrant permanent discontinuation 1

Prevention Strategies for Subsequent Infusions

Standard premedication protocol (should have been given but reinforce for next cycle):

• Acetaminophen 1000 mg orally 30-60 minutes before infusion 1, 2
• Antihistamine (diphenhydramine 50 mg or equivalent) 30-60 minutes before infusion 1, 2
• Slow initial infusion rate is critical—start at 50 mg/hour and escalate gradually only if tolerated 2

Important Clinical Context

Infusion reactions occur in 77% of patients on first rituximab infusion, with severe reactions in approximately 10% 1. The incidence decreases dramatically with subsequent infusions 2, 3. These reactions typically occur within 30-120 minutes of starting the infusion 2.

For hairy cell leukemia specifically, patients may have high circulating malignant cell counts, which increases the risk of severe cytokine-release reactions 2. These patients require particularly close monitoring during the first infusion.

Critical Pitfalls to Avoid

• Do not permanently discontinue rituximab for Grade 1/2 reactions—these are manageable and expected, particularly on first infusion 1, 3, 4
• Do not resume infusion at the same rate—always reduce to at least 50% of the rate that caused symptoms 1
• Do not confuse infusion reactions with true IgE-mediated anaphylaxis—most rituximab reactions are cytokine-release syndrome, not allergic hypersensitivity 5
• Monitor for biphasic reactions—observe patients for several hours after severe reactions, as symptoms can recur 1

Rechallenge Considerations

Most patients who experience rigors can safely continue rituximab therapy with appropriate premedication and slower infusion rates 3, 4. However, if Grade 3 reactions recur at a subsequent infusion despite these measures, permanent discontinuation should be considered 1.

The key is distinguishing between manageable cytokine-release reactions (which respond to slowing/stopping the infusion and symptomatic treatment) versus true severe hypersensitivity reactions (which may require permanent discontinuation and consideration of alternative anti-CD20 agents).