As a pharmacist working in the field of biologics, patients often comment on how they appreciate the way I describe how each medication works in the body. Recently, I was asked to put in writing what I had verbally explained about the medication rituximab (Rituxan).
I am sharing that with you in the blog today and will continue to write a series on different medications used in auto-immune diseases. Feel free to put in requests for medication you would like explained as I have done below. Stay tuned…
How Rituximab (Rituxan) Works
Rituximab works by destroying a specific type of B cell which is in the “head office” of the immune system. We feel that these B Cells are directing the production of excess inflammation in Rheumatoid Arthritis.
When Rituxan is given and the B cells in the circulation are destroyed, these cells will release inflammatory chemicals from inside themselves. This could make a person very uncomfortable during an infusion. For this reason, pre-medications are always given before the infusion. Acetaminophen, an antihistamine called Benadryl and a steroid called Solucortef are all part of the pre-medications. As the steroid can significantly reduce inflammation, people can often feel quite a bit better for a couple of days after an infusion. This is not the Rituxan working yet.
Once the first dose of Rituxan is given, the B cells that are produced in the bone marrow, will be released into the circulation to replace the ones Rituxan has destroyed. Therefore, a second dose of Rituxan is given 2 weeks later, to destroy the new B Cells just released. After this second dose, it usually takes 6 months for the B Cells to be produced back to the same level they were initially.
Therefore, the Rituxan is given again 6 months later.
If someone is making B Cells quicker than the 6 months their condition may begin to flare earlier. If this is happening discuss this with your rheumatologist.
Carolyn Whiskin is the Pharmacy Manager for Charlton Health. Carolyn specializes in the treatment of autoimmune diseases, pharmaceutical compounding, women’s health, pain and smoking cessation. Carolyn has won provincial and national awards for her commitment to patient care and public service.