How Rituxan Works

In some people with inflammatory arthritis, the cells of the immune system become confused. They mistake the cells of the body’s own joints for foreign invaders and decide to “attack” them. Arthritis that is caused by this activity may be called an autoimmune disease.

The B-cell is a type white blood cell that forms part of the body’s immune system. It is partly responsible for this attack on the joints.

Rituxan is a specially-designed protein called a chimeric monoclonal antibody that targets a specific protein found on the surface of B-cells called CD20. When Rituxan binds to the surface of a B-cell, it causes their destruction.

By deleting B-cells from the body, Rituxan works to suppress a part of the body’s immune system. Although this suppression may make it slightly harder for patients to fight off infections, it also helps to stabilize an overactive immune system.

Side Effects of Rituxan

Some side effects or reactions may occur for some patients during or shortly after the infusion.

Patients who take Rituxan can very rarely develop a serious brain infection. Patients should call a doctor immediately if they experience changes in mental state, decreased vision, or problems with speech or walking. These symptoms may start gradually and get worse quickly.

MORE COMMON side-effects include:

  • Abdominal pain, nausea, and diarrhea
  • Sore muscles or joints
  • Rash, hives, or itchiness
  • Headaches, dizziness, or tingling
  • Sore throat, fever, chills, & general weakness
  • Increase in blood pressure

RARE side-effects include:

  • Infusion Reaction – Many patients will react to the medication during or shortly after the infusion, most likely during the first infusion and less so with future infusions. Most of these reactions are not severe.
  • Infection – As is the case with many medications used in the treatment of arthritis there is an increased risk of serious infections associated with the use of Rituxan. Any infections or fevers should be taken very seriously and reviewed by a doctor.
  • Rare brain infection – Patients have very rarely developed a rare brain infection called PML while taking Rituxan.
  • Skin – Severe skin reactions have been reported with Rituxan.
  • Heart – Rituxan has been associated with abnormal heart rhythms. Patients who have known heart rhythm problems should discuss them with their doctor to understand the potential impact of this medication.
  • Blood Counts – Rituxan can cause a drop in the numbers of white blood cells (which are needed to fight infection) or red blood cells (which carry oxygen). This is very rare and it is unusual for this to be a serious problem.

Who Should NOT Take Rituxan

People who should NOT take Rituxan include:

  • Those who have had a previous serious allergic reaction to Rituxan
  • Women who are pregnant, planning on becoming pregnant, or breast feeding
  • Patients with active infections (such as tuberculosis or hepatitis B)
  • Patients with a history of hepatitis B or are carriers of the disease

Anyone who becomes pregnant while taking Rituxan should notify their doctor immediately.

When to Call a Doctor

Patients should call their doctor if they feel sick and want to stop, or they are concerned about any side effects.

Other reasons to call a doctor while taking Rituxan include:

  • Fever or possible infection
  • If another doctor has prescribed antibiotics to fight an infection
  • Before having surgery
  • Pregnancy or planning on becoming pregnant
  • Planning to get any vaccinations
  • Rash

Rituxan Video

Watch Dr. Andy Thompson, a Canadian rheumatologist, introduce Rituxan.