The most common side effects of rituximab are allergic reactions to the infusion, infections, itching, high blood pressure, nausea, fever, and joint pain. Serious, life-threatening side effects can also occur but are rare.

Studies looked at people with RA taking rituximab + methotrexate (MTX). They compared them to similar people with RA taking a placebo + methotrexate. A placebo (sugar pill) does not contain any medicine. Studies use it to figure out what symptoms are actually due to medicine versus those that would occur normally. This table shows the most common side effects of rituximab found in these studies.

Rituximab Side Effects

Let’s Do the Math

For example, itching occurs in both RA study groups. Itching occurred in:

  • 5 out of 100 people taking rituximab + MTX
  • 1 out of 100 people taking placebo + MTX

    So, 5 – 1 = 4 people
    Itching may be due to rituximab in 4 out of 100 people.

Serious Side Effects

  • Infusion Reactions: Rituximab is given by IV to treat RA. It is usually given with methotrexate (MTX). At doses given for RA, about 1 in 3 people have a reaction to it. Reactions usually happen within hours of the start of the IV. Your healthcare provider will watch for symptoms. These include headache, fever, sweats, itching. Some people have difficulty breathing or swelling of the tongue or tightening in the throat. Usually, the symptoms get better if the IV is stopped. Often, the medicine can be safely given later at a lower dose. Less than 1 out of 100 people will have a serious reaction. These can include very low blood pressure, anaphylaxis, shock, heart or breathing problems, and death.
  • Infections: About 5 out of every 100 people taking rituximab will have an infection. Most are similar to a cold or bronchitis. Symptoms may include a runny or stuffy nose, scratchy or sore throat, and cough. Some people may have a urinary tract infection. Luckily, serious infections are less common. About 2 people out of 100 get a serious infection, such as pneumonia or sepsis. Also, people who were sick with hepatitis B in the past may get sick again when they take rituximab.
  • Other Side Effects: Other rare, but serious, side effects have happened after taking rituximab for RA. These include severe skin reactions. They can occur up to 3 months after infusion. A life-threatening nervous system infection has happened in a small number of people after taking rituximab. This infection is called progressive multifocal leukoencephalopathy (PML). It started up to 18 months after treatment. The risk of PML is about 1 out of every 25,000 people taking rituximab.

The Bottom Line

All medicines can cause side effects. All people react differently to medicines. As studies show, not everyone gets side effects from rituximab. Your healthcare provider can help you weigh the risks and benefits of this medicine.

Ask your doctor if it’s okay to take rituximab for your RA!