Rituximab (Rituxan)  

Brand name: Rituxan^®  

Generic name:rituximab    

Therapeutic Class: monoclonal antibody 

Manufacturer / Distributor: Genentech, Inc  

Availability:  rituximab is available by prescription only  

FDA Approval: In 1997, Rituximab was approved by the U.S. Food and Drug Administration (FDA) for use in the treatment of B cell non-Hodgkin lymphoma resistant to other chemotherapy drugs.  The drug may be approved for more uses, talk to your physician or pharmacist for information.  

Indications: rituximab is used alone or in combination with other medications to treat: 

• rheumatoid arthritis   
• follicular lymphoma stage III-IV that is resistant to chemotherapy or relapse after chemotherapy;  
• follicular lymphoma Stage III-IV that had never been previously treated, in combination with CVP chemotherapy;  
• Aggressive diffuse large b-cell CD20-positive Non Hodgkin's lymphoma (DLBCL), in combination with CHOP chemotherapy.   

Rituximab may also be prescribed to treat other medical conditions that are not mentioned in this article; talk to your doctor or pharmacist for more information. 

Dosage form: rituximab  is given by injection into a vein 

Dosage:   The dose of rituximab recommended to you can vary depending on your age, type of cancer being treated, and your body surface area (BSA) . If you are taking other drugs, you may be prescribed lower doses of rituximab.  

Usually, rituximab is injected into a vein through an intravenous infusion site. The drug must be administered in a hospital or health center that has sterilization equipment for its preparation. In absence of complications, rituximab must be injected once weekly for 4 weeks. Rituximab should be administered with great care by an oncologist or a health professional that has experience in drug chemotherapy.   

Like most chemotherapy drug, Rituximab can damage the bone marrow, and cause a number of side effects: nausea, vomiting, fatigue, etc. These effects are temporary and vary from one patient to another; it is important to continue the treatment if there is no complications.  

However, it is important to always report to your doctor the reaction of your body to the medication. Some people who receive Rituximab may develop severe health problems. In fact, some die within 24 hours after they receive a dose of Rituximab. Most of these deaths happened after the first dose of rituximab. Tell your doctor if you have or have ever had chronic lymphocytic leukemia (CLL), a type of cancer that begins in the white blood cells; mantle cell lymphoma, a fast-growing cancer that begins in the cells of the immune system; irregular heartbeat; or heart or lung disease. 

Mechanism of action (MOA):  Rituximab is a monoclonal antibody, a class of chemotherapy drugs; it slows or stops tumor progression by killing cells that multiply rapidly (cancer cells and some normal cells).  

Overdose:  Rituximab is given in hospital by professionals; although it is not impossible, the risk of overdose is very difficult. An overdose of paclitaxel may cause a life threatening decrease in the number of blood cells in your bone marrow and cause severe health problems. Even in the absence of overdose, rituximab can cause severe reactions in some patients. Contact your health care provider immediately if you experience: fainting; shortness of breath, blurred vision, pounding or irregular heartbeat, loss of consciousness, swelling of the lips, tongue, or throat. Difficulty breathing or swallowing should be reported immediately to your doctor. 

In the treatment of non-Hodgkin's lymphoma,  Rituximab can lead to the development of tumor lysis syndrome (a serious metabolic disorder that is due to fast breakdown of cancer cells), which tend to lead to kidney failure and the need for dialysis treatment.  Some patients die within 24 hours after receiving a dose of rituximab. Before starting the treatment, it is extremely important to tell your doctor all details about your medical history. During and after the treatment, keep all appointments with your doctor.  

Missing dose:  Rituximab is administered in hospital; it is basically difficult for you to miss any dose if you keep all appointments of your doctor.  Therefore, be present at each appointment to take all doses of paclitaxel that your doctor has prescribed. If for some reasons you cannot go to the hospital for the treatment, contact your oncologist before the date scheduled for the injection.  

Contraindications:   Rituximab is contraindicated or should be used with precaution in the following conditions: 

• respiratory failure  
• filling of airspaces with fluid (pulmonary oedema)  
• antihypertensive therapy   
• angina   
• heart failure  
• neutropenia  
• thrombocytopenia  
• women who are breast-feeding  
• having a high number of circulating malignant cells   
• allergy to Rituximab or one of its ingredients   
• allergy to Chinese hamster ovary (CHO) cells  
• Pregnant women - if you are at childbearing age, talk to your doctor about contraception during treatment with Rituximab. 

Interactions:  if you are taking Rituximab, tell you to your doctor before taking aspirin,  vitamins, nutritional supplements, or St. John's wort. Certain medications can interact with  Rituximab, and increase the risk of side effects. Tell your doctor or pharmacist if you are taking any of these medications:      

• vaccines   
• cisplatin  
• echinacea  
• Medicines for hypertension.   

Side effects:  In addition to cancer cells, rituximab also attack normal cells that multiply rapidly, causing adverse reaction in some patients. Common rituximab side effects include:  

• hair loss 
• nausea and vomiting  
• loss of appetite  
• change in taste  
• runny nose  
• heartburn  
• weight gain  
• muscle or back pain  
• flushing  
• night sweats  
• joint pain   
• fatigue  
• sleep disorders  
• Mouth blistering.   

If the side effects above persist for weeks, contact your oncologist. In addition, contact your doctor if you experience any of these symptoms:    

• cervical cancer  
• endometrial cancer  
• stomach pain  
• unusual bruising or bleeding  
• sore throat, fever, chills, or other   
• chest pain or tightness  
• severe muscle or joint pain   
• signs of infection such as sore throat, fever and chills  
• joint pain or soreness 
• blood in urine or stools  
• pain in lower back or the side  
• Painful or difficulty urinating.  

References: 

1 - wikipedia.org, Rituximab 

2 - nlm.nih.gov, medlineplus: Important Warning (about Rituximab)  

3 - http://www.rituxan.com/lymphoma/hcp/indications/DLBCL/index.m