What are the side effects of Rituximab (Rituxan)?

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Last updated: April 7, 2025 • View editorial policy

From the Guidelines

Rituximab can cause several side effects, including infusion reactions, fatigue, weakness, and increased risk of infections, with the most common side effects being infusion reactions, which occur in 77% of patients during the first administration, as reported by 1.

Common Side Effects

  • Infusion reactions (fever, chills, nausea, headache, itching, and rash) typically occur during or within 24 hours of receiving the medication
  • Fatigue, weakness, and increased risk of infections due to decreased white blood cell counts ### Serious Side Effects
  • Severe skin reactions, hepatitis B reactivation in carriers, progressive multifocal leukoencephalopathy (PML, a rare brain infection), tumor lysis syndrome, and cardiac problems
  • Blood disorders such as neutropenia, thrombocytopenia, and anemia can occur ### Management of Side Effects
  • Premedication with acetaminophen, antihistamines, and sometimes corticosteroids is typically given before infusions to reduce infusion reactions, as recommended by 1
  • Patients should be monitored during infusions and report any unusual symptoms promptly
  • Risk stratification algorithms, such as the one proposed by Levin et al, can be used to evaluate patients after a rituximab infusion reaction, as described by 2 ### Recent Guidelines
  • The 2022 practice parameter update on drug allergy recommends a risk-stratification approach to managing rituximab infusion reactions, as outlined by 2 and 3
  • The update also highlights the importance of shared decision making with patients and considering the risks and benefits of treatment, as emphasized by 2

From the FDA Drug Label

RITUXAN can cause serious side effects, including: Tumor Lysis Syndrome (TLS). Serious infections. Heart problems Kidney problems, especially if you or your child are receiving RITUXAN for NHL. Stomach and Serious bowel problems that can sometimes lead to death The most common side effects of RITUXAN include: infusion-related reactions infections (may include fever, chills) body aches tiredness nausea In adults with GPA or MPA the most common side effects of RITUXAN also include: low white and red blood cells swelling diarrhea muscle spasms In children with B-cell NHL or B-AL who receive RITUXAN with chemotherapy, the most common side effects include: decreased white blood cells with fever mouth sores inflammation of the upper intestine serious infection throughout the body and organs (sepsis) changes in liver function blood tests low level of potassium in the blood Other side effects with RITUXAN include: aching joints during or within hours of receiving an infusion more frequent upper respiratory tract infection

The side effects of rituximab include:

  • Serious side effects: + Tumor Lysis Syndrome (TLS) + Serious infections + Heart problems + Kidney problems + Stomach and bowel problems
  • Common side effects: + Infusion-related reactions + Infections + Body aches + Tiredness + Nausea + Low white and red blood cells + Swelling + Diarrhea + Muscle spasms + Decreased white blood cells with fever + Mouth sores + Inflammation of the upper intestine + Serious infection throughout the body and organs (sepsis) + Changes in liver function + Blood tests + Low level of potassium in the blood + Aching joints + More frequent upper respiratory tract infection 4

From the Research

Side Effects of Rituximab

The side effects of rituximab can be categorized into several areas, including:

  • Infectious events: Rituximab has been associated with a small risk of serious infectious events, which is stable over time and repeat courses 5. Opportunistic infections are rare, but reactivation of hepatitis B remains a concern 5, 6, 7.
  • Infusion-related reactions: Infusion-related reactions are more likely with the initial infusion and are usually mild 5, 8.
  • Hypogammaglobulinemia: Rituximab may cause hypogammaglobulinemia, but any risk of subsequent increased infectious events is not yet well established 5.
  • Progressive multifocal leukoencephalopathy (PML): There is a possible association between rituximab and PML, a lethal encephalitis caused by the polyomavirus JC 5, 6, 9.
  • Malignancies and cardiovascular events: Malignancies and cardiovascular events do not appear to be increased with rituximab use 5.
  • Hepatitis B virus reactivation: Rituximab therapy is associated with a high risk of hepatitis B virus reactivation in patients with chronic or resolved hepatitis B 7.

Specific Risks

Some specific risks associated with rituximab include:

  • HBV reactivation: The risk of HBV reactivation is high, regardless of underlying disease or HBsAg status 7.
  • PML: The risk of PML is rare, but it is a serious and usually fatal CNS infection 9.
  • Infusion-related reactions: The risk of infusion-related reactions is higher with the initial infusion and can be fatal in rare cases 8.

Patient Screening and Precautions

Before initiating rituximab, patient screening for:

  • Hypersensitivity to murine proteins
  • Infections
  • Congestive heart failure
  • Pregnancy
  • Hypogammaglobulinemia is imperative 5. Vaccinations should be administered prior to treatment whenever possible 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.