Rituximab

Rituximab

Rituximab emerged as a groundbreaking monoclonal antibody medication. Doctors use it to treat several autoimmune diseases and cancer types. The drug has proven its worth in managing conditions like non-Hodgkin lymphoma, chronic lymphocytic leukaemia and rheumatoid arthritis. Doctors found new ways to help patients with this treatment beyond its original purpose. The drug now helps treat rare conditions like immune thrombocytopenic purpura and Rasmussen encephalitis. This article explains its mechanisms in the body, proper administration methods, side effects, and key precautions.

What is Rituximab?

Rituximab is a specialised anti-CD20 monoclonal antibody. The protein targets CD20 markers on B cells, which makes it effective for B cell-related diseases. Doctors give it in injection or infusion form.

Rituximab Uses

Rituximab helps to treat many cancerous and non-cancerous conditions. These are:

• Non-Hodgkin's lymphoma (various types)
• Chronic lymphocytic leukaemia
• Rheumatoid arthritis (when TNF therapy hasn't worked)
• Granulomatosis with polyangiitis and microscopic polyangiitis
• Pemphigus vulgaris

How and When to Use Rituximab

Rituximab comes as an infusion only, not a tablet. Doctors must administer this medicine in a clinical setting. Patients receive acetaminophen and antihistamines before each infusion to minimise reactions. Each treatment session lasts several hours, and the initial treatment usually involves two infusions spaced two weeks apart.

Rituximab Side Effects

Most patients (80-90%) experience infusion reactions within 30-120 minutes after treatment begins. Common side effects are:

• Bleeding gums
• Blood in urine or stool
• Nausea and vomiting
• Headaches and body pain
• Chills
• Dizziness
• Dry mouth and mouth sores

Lymphopenia, serious skin & mouth infections, and heart problems are other serious side effects.

Precautions

• Patients need Hepatitis B screening before treatment since rituximab can reactivate the virus.
• Women should use contraception during treatment and continue for 12 months after completion.
• Pregnant women should tell their doctor before receiving the drug, as it may harm the unborn babies.
• This medicine increases your risk of infections, so avoid people who are sick.

How Rituximab Works

Rituximab functions as a monoclonal antibody that targets a specific protein called CD20 found on B cells. The drug works through multiple mechanisms after attaching to these cells:

• Your immune system gets help to identify and destroy marked cancer cells
• The drug triggers complement-mediated cytotoxicity (direct cell killing)
• Your body experiences antibody-dependent cell-mediated cytotoxicity
• The medicine directly causes structural changes and apoptosis (cell death)

Can I Take Rituximab with Other Medicines

You should exercise caution because rituximab interacts with many medicines. Common interactions are:

• Blood pressure medicines
• Cisplatin
• Disease-modifying antirheumatic drugs
• Infliximab
• Live vaccines
• Other immune-suppressing medicines
• TNF blockers
• Warfarin

Dosage Information

Each condition requires different dosing:

• Non-Hodgkin's lymphoma: Patients typically receive 375 mg/m² once weekly for 4-8 weeks
• Rheumatoid arthritis: Treatment involves two 1000 mg infusions separated by two weeks
• Chronic lymphocytic leukaemia: Patients start with 375 mg/m² for first cycle, then move to 500 mg/m² for cycles 2-6

Doctors must administer rituximab in a medical setting. Patients receive appropriate premedication to reduce infusion reactions.

Conclusion

Rituximab is a monoclonal antibody that targets B cells with precision and helps patients with lymphomas, leukaemia and autoimmune disorders. Medical staff can give rituximab through an infusion. Patients get their treatment over several hours while the medical team watches for any reactions. Each condition needs its own dosage and most treatments follow a schedule that spans multiple weeks.

These precautions aside, rituximab proves its worth as a crucial medicine worldwide. More doctors use it for off-label treatments now than ever before, which shows how much they value this option. Rituximab often works when other treatments don't, giving hope to patients with tough diagnoses.

FAQs

1. Is rituximab high risk?

Rituximab comes with several serious risks. Infusion reactions affect 80-90% of patients. These reactions usually happen within 30-120 minutes after the first infusion. The most important risks include:

• Infections (bacterial, viral, or fungal) due to lowered immune function
• Hepatitis B reactivation, which can cause liver failure
• Progressive multifocal leukoencephalopathy (PML), a rare but deadly brain infection
• Heart problems, including irregular heartbeat

2. How long does rituximab take to work?

You won't see results right away. Rheumatoid arthritis patients usually notice improvements between 8-16 weeks after treatment begins. Cancer patients with non-Hodgkin's lymphoma typically respond around 50 days (about 7 weeks). Kidney disease patients often see changes within 4-6 weeks.

3. What happens if I miss a dose?

Contact your doctor's office right away. Your symptoms might flare up if you skip doses. Your healthcare team will work to reschedule your infusion quickly.

4. What happens if I overdose?

Overdose patients face higher risks of severe reactions that can be fatal during infusion. Medical staff will provide symptomatic and supportive care.

5. What not to take with rituximab?

Stay away from:

• Live vaccines (chickenpox, MMR, yellow fever)
• TNF blockers
• Any medications without your doctor's approval

6. Who cannot take rituximab?

Rituximab isn't safe for people with:

• Active severe infections
• Severe heart failure
• History of rituximab allergies
• HIV infection
• Hepatitis B (unless treated before starting)

7. When should I take rituximab?

Rituximab differs from regular medicines since patients can't take it themselves. Doctors must administer this medication in a hospital or clinic setting. The treatment consists of an intravenous infusion that lasts four to six hours. Doctors create specific infusion schedules based on each patient's condition.

8. How many days to take rituximab?

Each condition needs a different treatment duration. Rheumatoid arthritis patients usually receive two infusions two weeks apart. Patients with vasculitis might need four weekly infusions. Maintenance treatments typically happen every six months after that.

9. When to stop rituximab?

Your doctor will decide the right time to end your treatment. Maintenance treatments can last 24-48 months. Doctors might stop treatment for pemphigus patients who maintain complete remission with low antibody levels for at least one year.

10. Is it safe to take rituximab daily?

Rituximab doesn't work as a daily medication. The treatment follows specific schedules with weeks or months between doses. This spacing allows proper B-cell depletion while reducing side effects.

11. What is the best time to take rituximab?

The gap between doses matters more than the actual time of day. Afternoon appointments might suit patients on blood pressure medications better, as doctors often recommend pausing these medications 12 hours before treatment.

12. What to avoid when taking rituximab?

After your infusion, avoid:

• Live vaccines (wait at least six months after treatment)
• Pregnancy (use contraception during treatment and 12 months after)
• Crowded places during periods of lowered immunity