Rituximab (Rituxan)

What Is Rituximab?

Rituximab (pronounced [ri TUK si mab]) is also known by the brand name, Rituxin. Rituximab is a type of chemotherapy, and it is an antineoplastic (anti-cancer) drug that belongs to a class called anti-CD20 monoclonal antibodies. 

Based on Rituxan, several different biosimilars have been produced, including Riabni, Ruxience, and Truxima. 

Rituxan is also considered an immunosuppressant as it has a role in suppressing the immune system. Rituximab attacks the targeted cells, and some of the healthy cells are also damaged in the process. 

Although it is chemotherapy, it is not considered a hazardous agent.

What Is Chemotherapy?

Chemotherapy is a cancer treatment in which certain drugs are used to kill cancerous cells. Chemotherapy drugs are usually cytotoxic chemical substances that are toxic to the cells, restrict their growth, prevent their division, and ultimately kill the cells.

How Is Rituxan Used?

Rituxan has been approved by the Food and Drug Administration (FDA) as a first-line agent to treat several different cancerous and non-cancerous indications including chronic lymphocytic leukemia (CLL), Non-Hodgkin’s lymphoma (NHL), polyangiitis, pemphigus vulgaris, and rheumatoid arthritis. It is also commonly used for several other indications.

Rituxan may be used in combination with other drugs, including chemotherapy agents.

Available Formulations

Rituxan is only available as an intravenous injection. The solution in the vial should be clear/colorless.

Directions for Use

Rituximab is typically given over a few hours (anywhere between 3 to 8 hours), but it could be given in less time if well tolerated. This medication is typically dosed once per week. The length of infusion and frequency is dependent on the indication for use and severity. Be sure to verify the correct dose and frequency with your provider. 

The typical rate for the initial infusion is 50 mg/hr and can be increased to a maximum rate of 400 mg/hr. Dilute Rituxan in an infusion bag with normal saline or 5% dextrose in water. Gently invert to mix and do not shake. Do not mix or dilute with any other medications. Any unused portion left in the vial must be discarded.

Premedication

Premedication is highly recommended prior to infusion with Rituxan to reduce the symptoms of the infusion. Premedication should be given approximately 30 minutes before infusion. Premedication options can include a pain reliever (like acetaminophen/Tylenol), an antihistamine (like diphenhydramine/Benadryl), and a steroid (like methylprednisolone).

Missed Dose

If you have missed an appointment for a Rituxan infusion, consult your physician immediately to reschedule.

Storage

Rituxan vials must be stored in the refrigerator. Once diluted, it can be stored in the refrigerator for up to 24 hours and then at room temperature for an additional 24 hours (refrigeration is preferred). Do not freeze and do not shake. Keep the vials protected from light by keeping them stored in their original containers.

What To Avoid While Taking Rituxan?

While on Rituxan therapy, you must follow some precautions. Always tell your physician about any medication you are already taking. Do not take any drug or medicine (even herbals or over-the-counter medications) without prior consent from your physician or pharmacist, as they may interact with Rituxan.

Avoid any kind of immunization or vaccination without prior consent from your physician. Avoid alcohol as it may enhance the side effects of the treatment. A common side effect during and immediately after treatment is dizziness; therefore, avoid driving or any task that may require concentration.

Pregnancy and Rituxan

Females of childbearing age must use effective contraception during treatment and for 12 months after the last dose. Since Rituxan can be present in breast milk and may cause fetal harm, it is not recommended for women who are breastfeeding.

However, there are certain cases where the benefits outweigh the risks, and in such cases, the physician may decide in favor of administering Rituxan during pregnancy or while breastfeeding.

Side Effects

Although it is generally well-tolerated, you may encounter many side effects while taking Rituxan. A few things to keep in mind are: 

• You may not have all the side effects listed below. Many people may experience little to no side effects.
• The severity of side effects may vary from person to person, so don’t compare your side effects with other people’s experiences.
• Most of the side effects will improve when therapy is discontinued.
• These side effects are easily manageable most of the time, either by readjusting the dose of Rituxan or using additional medications to treat the symptoms. Consult with your physician or pharmacist to explore the available options.
• Do not hide any symptoms; when you feel any discomfort, do not hesitate to tell your physician or pharmacist about it. 

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Some of the more serious side effects of Rituxan are:

Tumor Lysis Syndrome (TLS)

TLS is caused by the fast breakdown of cancer cells (bursting of the cells). TLS can cause you to have kidney failure and the need for dialysis. It may also cause an abnormal heart rhythm. TLS can happen within 12 to 24 hours after an infusion of Rituxan. Tell your healthcare provider right away if you have any of the following signs or symptoms of TLS: nausea, vomiting, diarrhea, or lack of energy.

Serious Infections

There may be a high chance of acquiring an infection while on Rituxan therapy. Infections may include fungal, bacterial (like pneumonia), or viral infections (like hepatitis B). If a patient previously had hepatitis B, Rituxan may lead to the reactivation of the viral infection even several months after its discontinuation. Signs of hepatitis B include yellowing of the skin and eyes or excessive tiredness. In order to minimize the risk for infection, it is important to avoid crowds, unhygienic street foods, certain vaccines, etc. Early symptoms of infection may include cough, chills, fever, flu, or trouble breathing. Premedication with a steroid and antihistamine may help reduce any symptoms. If you acquire an infection, immediately seek advice from your physician. 

Heart Complications

Rituxan may cause chest pain, irregular heartbeats, and a heart attack. Your healthcare provider may monitor your heart during and after treatment with Rituxan if you have symptoms of heart problems or a history of heart problems. Tell your healthcare provider right away if you have chest pains or irregular heartbeats during treatment with Rituxan.

Stomach and Serious Bowel Problems

Bowel problems, including blockage or tears in the bowel, can occur, especially in those taking Rituxan in combination with other chemotherapy agents. Tell your healthcare provider right away if you have any stomach pain during treatment with Rituxan.

Bone/Joint Pain

Another common side effect includes bone, muscle, joint, or even back pain. Adequate rest and hydration may help reduce potential bone, joint, or back pain. Over-the-counter acetaminophen (Tylenol) may be a good option to relieve some of these pains. Consult your physician if these pains become intolerable or are affecting your normal daily functions. 

Progressive Multifocal Leukoencephalopathy (PML)

PML is a rare, serious brain infection caused by a virus, and is more common in those who have a weakened immune system. It causes an imbalance of electrolytes (like calcium, potassium, phosphate, etc.) in the body. In the worst cases, PML can result in severe disability or death. There is no known treatment, prevention, or cure for PML. Contact your physician immediately if you are experiencing any of the following symptoms: confusion, dizziness or loss of balance, difficulty walking or talking, decreased strength or weakness on one side of your body, or vision problems like blurred vision or loss of vision.

Kidney Complications

Rituxan can cause severe kidney problems, especially if you are receiving Rituxan for Non–Hodgkin’s lymphoma (NHL). Call your doctor right away if you experience puffiness in your face or ankles, blood in your urine, brown-colored urine, or if you notice you urinate less than usual. This complication may also be a result of PML.

Severe Skin and Mouth Reactions

Severe skin and mouth reactions are also known as mucocutaneous reactions, and they can include paraneoplastic pemphigus, Stevens-Johnson syndrome (SJS), lichenoid dermatitis, vesiculobullous dermatitis, and toxic epidermal necrolysis (TEN). Some of these reactions may be life-threatening. Tell your healthcare provider or get medical help right away if you experience any of these symptoms at any time during treatment: painful sores or ulcers on the skin, lips, or mouth; blisters; peeling skin; rash; or pustules. 

Infusion-related Reactions

Infusion-related reactions are very common side effects of Rituxan treatment and most commonly occur during treatment or within 24 hours after infusion. This side effect is the main reason premedication is necessary. Infusion-related reactions can present as hives (red itchy welts) or rash; itching; swelling of your lips, tongue, throat, or face; sudden cough; shortness of breath; difficulty breathing, or wheezing; weakness; dizziness or feeling faint; palpitations (feeling like your heart is racing or fluttering); or chest pain.

Allergic Reactions

Allergic reactions are another rare side effect of Rituxan. A mild allergic reaction can include a rash on the skin, skin becoming itchy, etc. Severe side effects may include swelling under the eyes, lips, or hands, and throat or tongue swelling with disturbed breathing. Immediately contact your physician if any signs of an allergic reaction are present. 

Other common side effects may include:

• Weight gain
• Headache
• Fever or chills
• Stomach pain
• Diarrhea
• Heartburn
• Flushing
• Night sweats
• Weakness or fatigue
• Stuffy/runny nose
• Anxiety
• Depression

Precautions

Unless approved by your physician, Rituximab is generally not recommended for: 

• Patients with a history of cardiac complications like heart attacks or cardiac arrhythmias or who experience this during therapy.
  • Blood pressure should be monitored regularly while on therapy.
  • If cardiac arrhythmia occurs during therapy, discontinuation of rituximab is highly recommended.
• Patients who develop PML during therapy. If PML develops during therapy, discontinuation of rituximab is highly recommended.
• Patients who develop severe mucocutaneous reactions like SJS or TEN. If a severe mucocutaneous reaction occurs, discontinuation of rituximab is recommended.
• Patients with severe kidney impairment. If severe kidney damage occurs during therapy, permanent discontinuation is recommended.
• Patients with active hepatitis B, hepatitis C, HIV, tuberculosis, or other severe infection or who have a reactivated hepatitis B infection.
  • For patients who have active viral infections, the physician may decide against using Rituxan and may choose a different medication, depending on the situation.
  • If reactivation of the hepatitis B virus occurs during therapy, immediate discontinuation of therapy is recommended.
• Patients who have a severe infusion-related reaction during therapy.
  • If a non-severe reaction occurs, stop the infusion or slow the infusion rate.
  • If a severe reaction occurs, discontinuation of Rituxan is recommended.

What To Expect Post-infusion With Rituxan

Rituxan infusions may feel a little draining, especially if it is the first infusion. The infusion may make you feel sick and unwell for a few days. Keep this in mind before scheduling your infusion, because in some cases, you may need to schedule time off work after the infusion.

Rituxan affects different people in different ways, and many of these effects usually occur within hours of receiving the infusion or the following day. They may also require a few days to subside. The more common post-infusion side effects can include:

• Fever (high temperature) or chills
• Nausea or vomiting
• Muscle aches or spasms
• Bone, joint, or muscle pain
• Headaches
• Weakness or tiredness
• Bruising or bleeding
• Nose bleeds or bleeding gums

Premedication is typically administered 30 minutes before the infusion, which can help reduce the chance and severity of all these side effects. Even though these are typical side effects post-infusion, it is essential to communicate any side effects you experience throughout your treatment to your physician. There may be other medications that could be taken to reduce any severe symptoms you may experience.

FAQs

Is Rituxan a chemo agent?

Chemo drugs are those that are used in the management of various cancers. Rituxan kills cancer cells and is thus a chemo agent. It is used as a treatment option for various cancer patients.

How long will it take to recover after each infusion?

It is very typical to feel unwell following an infusion of Rituxan. The symptoms usually appear within hours after the infusion, and some begin to appear the following day. These symptoms can take a few days to a week to subside, depending on the body and post-infusion care.

How is Rituxan taken?

Rituxan is only available in the form of an intravenous injection, and is typically given over a few hours and dosed once per week. The length of the infusion and frequency depends on the indication and severity. Verify the correct dose and frequency with your provider.

What should my health care provider know?

It is important to inform them of the following: 

• Any previous reaction to Rituxan or any other rituximab product.
• Any serious infections like hepatitis B, hepatitis C, HIV, or tuberculosis.
• Any vaccines you recently received.
• Any medications that you are currently taking including over-the-counter medications, vitamins, or herbal supplements.
• Any side effects you have experienced while being treated with Rituxan.