What is Rituxan (Rituximab)?

If your medical team has recommended Rituxan (rituximab), you’re probably trying to make sense of a lot of new information—how the treatment works, what the infusion process actually looks like, and what to realistically expect. That’s completely understandable, and you’re in the right place.

Rituxan is a monoclonal antibody: a targeted therapy that works with your immune system rather than broadly suppressing it. It has nearly three decades of clinical use behind it, and for many patients, it’s been an important turning point after other treatments haven’t provided enough relief.

This guide breaks down how Rituxan works, which conditions it’s approved for, what infusion visits involve, and what side effects to be aware of—so you can feel more prepared going in. If you’re new to specialty infusion therapy, understanding your medication is always a good place to start.

How Rituxan (Rituximab) Works in the Body

Rituximab (rituximab) is a targeted biologic therapy, designed to act on a very specific part of the immune system rather than affecting the whole body. Think of it as a precision signal that directs your immune system toward a particular problem.

The target is a protein called CD20, found on the surface of B-cell lymphocytes. B cells lymphocytes, also known as B cells, are a type of immune cell that play a normal role in how your immune system protects you, but in some conditions, they become the problem. In blood cancers, they can multiply abnormally and get out of control. In autoimmune diseases, they can mistakenly attack the body’s own healthy tissue.

When Rituxan enters the bloodstream through an IV, it circulates until it finds cells carrying the CD20 marker. Once attached, it signals other parts of the immune system to destroy those cells, helping to reduce the harmful B-cell activity that’s driving the disease.

Because healthy B cells also carry CD20, they’re affected too. In most patients, B cell counts begin to recover within about 12 months after treatment ends, as the body starts producing new B cells again.

Conditions Rituxan Is Approved to Treat

Rituxan (rituximab) is FDA-approved for several serious conditions. The common thread is that B cells play a central role in each, and reducing B-cell activity can help slow disease progression and ease symptoms.

For blood cancers, Rituxan is used to treat:

• Non-Hodgkin lymphoma (NHL): often given alongside chemotherapy
• Chronic lymphocytic leukemia (CLL): where abnormal B cells accumulate and crowd out healthy blood cells

For autoimmune conditions, it’s prescribed for:

• Rheumatoid arthritis (RA): given with another medication, methotrexate, when other disease-modifying treatments haven’t worked well enough
• Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA): inflammatory conditions that affect blood vessels
• Pemphigus vulgaris (PV): a rare autoimmune condition that causes painful skin blistering

Because these are all complex, ongoing conditions, coordinating treatment takes time and real support. Acelpa Health and its affiliated specialty pharmacies—California Specialty Pharmacy (CSP), ContinuumRx (CRx), Hawaii Specialty Pharmacy (HSP), Continuum Health (CH), and Integrated Care Systems (ICS)—support patients across a wide range of therapies and conditions, including complex infusion care like rituximab.

What to Expect During Your Rituxan Infusion

Rituxan (rituximab) is given intravenously, meaning each dose is delivered through an IV line at a clinic or infusion center. These are not quick visits—for most people, the first infusion takes 4 to 6 hours, and while later infusions often take less time, they still take 3 to 4 hours on average. Your care team starts at a slow rate and monitors closely, especially early on.

Before Your First Infusion

A few steps need to happen before treatment can begin:

• Hepatitis B screening: Rituxan can reactivate an inactive hepatitis B infection, so testing beforehand is a required safety step.
• Medication review: Your medical provider will go over your current medications to check for potential interactions.
• Vaccine timing: Live vaccines should not be given during treatment and for at least 6 months after treatment, since the immune system will be less responsive during this time.
• Premedication: On infusion day, you’ll typically be given medications ahead of the infusion to help reduce the risk of a reaction.

During the Infusion

Your care team will begin at a slow infusion rate and monitor you throughout, particularly during the first 30–120 minutes, when reactions are most likely to happen. If you’re tolerating the medication well, the rate will gradually increase. Your vital signs will be checked regularly.

Most patients find the whole process manageable, and it helps to bring something to pass the time—a book, headphones, or something to watch.

After the infusion, your team will continue to monitor your response over time with periodic blood work to keep tabs on cell counts and overall health.

Side Effects to Know About

Like most biologic therapies, Rituxan can cause side effects. Many are mild and short-lived, but some require prompt attention.

Common side effects which may happen during or after an infusion include:

• Fatigue, headache, or dizziness
• Mild fever or chills
• Nausea, vomiting, or diarrhea
• Itching, skin rash, or hives
• Muscle soreness, aches, or spasms
• Swelling of the lower limbs
• Changes in blood pressure
• Mild shortness of breath or coughatigue, headache, or mild fever

The most common reactions vary depending on the person and what condition is being treated.”

More serious side effects to report to your care team right away:

• Signs of infection, such as high fever, a persistent cough, or unusual fatigue that doesn’t improve
• Symptoms of progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection associated with rituximab use
• Tumor lysis syndrome, a risk for patients being treated for cancer
• Any new or worsening symptoms that feel out of the ordinary

Women who could become pregnant should use reliable contraception during treatment and for at least 12 months after the final dose. If you’re pregnant, planning to become pregnant, or breastfeeding, talk with your medical team before starting treatment.

If you have questions about managing side effects or understanding what’s normal versus what needs attention, the team at Acelpa Health’s affiliated pharmacies is available to help. You can also report side effects directly to the FDA at 1-800-FDA-1088.

Moving Forward with Rituxan—and the Right Team Behind You

Rituxan (rituximab) has been a meaningful part of cancer and autoimmune care for nearly three decades.

For many patients, it represents a real step forward when other options haven’t been enough, but it takes preparation, honest communication with your care team, and the right support in place to make the most of it.

Keeping up with infusion appointments, tracking how you feel between sessions, and staying open with your providers are all part of getting the best outcomes from treatment. You don’t have to figure it all out on your own.

Acelpa Health and its affiliated specialty pharmacies work closely alongside patients and their healthcare providers to help coordinate every part of the Rituxan process, from insurance approvals and medication delivery to qualifying manufacturer-sponsored and foundation financial coordination and ongoing support throughout treatment. We believe cost should never be a barrier to care. Our financial coordinators assess each patient’s individual situation and help explore options to cover medication costs, in accordance with all state, federal, and payor guidelines.

If you’re ready to get started or have questions about your treatment, connect with an Acelpa Health pharmacy. We’re here to help you navigate treatment with confidence.

Frequently Asked Questions (FAQ):

What is Rituxan (rituximab) approved to treat?

Some examples of FDA-approved indications for Rituxan (rituximab) include non-Hodgkin lymphoma, chronic lymphocytic leukemia (CLL), rheumatoid arthritis (RA), granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and pemphigus vulgaris (PV). In each case, it works by targeting CD20 proteins on B cells, helping to reduce the harmful immune activity driving the disease.

How long does a Rituxan (rituximab) infusion take?

Infusion times vary depending on your condition and how your body responds. The first session typically takes the longest (often 4 to 6 hours) because it starts slowly while your care team monitors for reactions. Later infusions may move faster if you tolerate the medication well.

How many infusions will I need?

This depends on your diagnosis and treatment plan. For certain cancers, Rituxan follows a structured schedule, often combined with chemotherapy. For autoimmune conditions like rheumatoid arthritis, it’s typically given as two infusions two weeks apart, then repeated every 6 months if needed. Your provider will outline the schedule that’s right for you.

What are the most common side effects of Rituxan (rituximab)?

The most commonly reported side effects include infections (may include fever, chills), body aches, tiredness, and nausea. Infusion reactions—such as flushing or shortness of breath—are most likely during the first session and are managed with premedication and careful monitoring throughout.

Can Rituxan (rituximab) affect my immune system?

Yes. Because Rituxan depletes B cells, it does affect the immune system’s ability to respond to certain infections. That’s why hepatitis B screening, vaccine timing, and regular blood work are all built into the treatment process. Your care team will monitor your labs and overall health throughout to stay ahead of any concerns.

Does Rituxan (rituximab) have biosimilar alternatives?

Yes. FDA-approved biosimilars to Rituxan, such as Ruxience and Truxima, are available and may be covered differently depending on your insurance plan. Your provider and pharmacy team can help determine which option makes the most sense for your situation.