[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Antineoplastic monoclonal antibodies](https://durgical.com/en/pharmacology/classes/antineoplastic-monoclonal-antibodies/) › Rituximab

# Rituximab

## Antineoplastic monoclonal antibodies?

Antineoplastic monoclonal antibodies

## High alert?

An error with this medicine can cause serious harm: double checks and protocols are used.

An anti-CD20 antibody that destroys B cells; a backbone of lymphoma and CLL treatment, also used in rheumatoid arthritis and vasculitis.

Updated Nov 1, 2026

Also called: anti-CD20 antibody

## Quick facts

**Group**
[Antineoplastic monoclonal antibodies](https://durgical.com/en/pharmacology/classes/antineoplastic-monoclonal-antibodies/)

**Target**
CD20 (B-lymphocyte surface antigen)

**Used for**
B-cell non-Hodgkin lymphomas · Pemphigus vulgaris

**Key effects**
Infusion reactions · Infections · Diarrhoea

**Monitor**
Hepatitis B surface antigen · Blood counts · Uric acid

**ATC**
L01FA01

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◆**CD20 (B-lymphocyte surface antigen)**Rituximab

ⓘ The cryo-EM structure shows the CD20 protein in the membrane with rituximab Fab arms bound to its large extracellular loop.

**Target in 3D:** CD20 (B-lymphocyte surface antigen). PDB structure 6VJA (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6VJA) · Drag to rotate · pinch to zoom

Rituximab is a chimeric mouse–human IgG1 antibody against CD20, a membrane protein present on normal and malignant B cells but not on stem cells or plasma cells. Once bound, it kills the B cell mainly through complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity. Circulating and tissue B cells are depleted for months and recover gradually. In autoimmune diseases the benefit comes from removing B cells that drive the attack.

- Binds CD20 on normal and malignant B cells
- Complement and immune effector cells are recruited
- B cells are lysed (CDC and ADCC)
- B-cell depletion lasts months

## Indications

- B-cell non-Hodgkin lymphomas, alone or with chemotherapy (e.g. diffuse large B-cell and follicular lymphoma). [Non-Hodgkin lymphoma →](https://durgical.com/en/conditions/non-hodgkin-lymphoma/)
- Chronic lymphocytic leukaemia, with chemotherapy. [Chronic lymphocytic leukaemia →](https://durgical.com/en/conditions/chronic-lymphocytic-leukaemia/)
- Rheumatoid arthritis after failure of a TNF inhibitor, with methotrexate. [Rheumatoid arthritis →](https://durgical.com/en/conditions/rheumatoid-arthritis/)
- Granulomatosis with polyangiitis. [Granulomatosis with polyangiitis →](https://durgical.com/en/conditions/granulomatosis-with-polyangiitis/)
- Microscopic polyangiitis. [Microscopic polyangiitis →](https://durgical.com/en/conditions/microscopic-polyangiitis/)
- Pemphigus vulgaris. [Pemphigus vulgaris →](https://durgical.com/en/conditions/pemphigus-vulgaris/)

## Adverse effects

### Common

- Infusion reactions: fever, chills, rigors, itching, mild low blood pressure, mostly with the first infusion
- Infections (respiratory and others)
- Diarrhoea, flushing, night sweats
- Low neutrophils

### Serious (rare, important)

- Severe or fatal infusion reactions within 24 hours
- Hepatitis B reactivation, sometimes with liver failure
- Progressive multifocal leukoencephalopathy (JC virus)
- Severe mucocutaneous reactions (Stevens-Johnson syndrome)
- Tumour lysis syndrome when many tumour cells circulate (CLL)
- Low immunoglobulins and late neutropenia
- Arrhythmias and chest pain during infusion

## Contraindications

- Previous severe reaction to rituximab
- Active severe infection, including untreated hepatitis B

## Key interactions

**Vaccines**
Vaccination needs are reviewed before starting; vaccines are not given during treatment without checking with the treating team.

## What is monitored

- Hepatitis B surface antigen and core antibody before starting
- Vital signs during each infusion
- Blood counts
- Immunoglobulin levels in long courses
- New neurological signs (PML)
- Uric acid, potassium and creatinine when tumour burden is high

## Administration and safety

- Intravenous infusion only, never as a push or bolus; the first infusion starts slowly and the rate is raised step by step.
- Premedication (antihistamine, paracetamol and often a corticosteroid) is given before each infusion as ordered.
- The intravenous and the subcutaneous (with hyaluronidase) products are not interchangeable; check the product and route.
- Emergency drugs and equipment for anaphylaxis are at hand during the infusion.

## Pregnancy and breastfeeding

Can harm the fetus; contraception is used during treatment and for months after, and breastfeeding is avoided.

## Nursing care

- Confirm hepatitis B screening before the first dose.
- Vital signs before, during and after the infusion; stop and call the team if wheeze, swelling of the face, chest pain or hypotension appear.
- Ask about fever, cough or other infections before each dose.
- Teaching: report yellow skin, dark urine, confusion, weakness or vision change, and painful mouth or skin sores.

## Pharmacokinetics

**Absorption**
Intravenous infusion (a subcutaneous form with hyaluronidase also exists).

**Elimination**
Removed like other IgG antibodies and partly by binding to B cells.

**Half-life**
About three weeks.

## Memory aid

Rituximab «rips up B cells» (CD20). Before you start, think «B before B»: check hepatitis B before killing B cells.

## Test yourself

Think of the answer, then tap the question to see it.

## What antigen does rituximab target, and which cells lack it?

CD20 on B cells; stem cells and plasma cells lack it.

## Which test is mandatory before the first rituximab dose?

Hepatitis B serology (surface antigen and core antibody), because of the risk of reactivation.

## A patient on rituximab develops progressive weakness and confusion months later. Which infection must be ruled out?

Progressive multifocal leukoencephalopathy caused by JC virus.

## When are infusion reactions most frequent, and how are they reduced?

With the first infusion; premedication and a slow, stepwise rate reduce them.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/rituximab/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**High alert**
An error with this medicine can cause serious harm: double checks and protocols are used.

## Connections

## Related drugs 3

- [Blinatumomab](https://durgical.com/en/pharmacology/blinatumomab/)
- [Ibrutinib](https://durgical.com/en/pharmacology/ibrutinib/)
- [Trastuzumab](https://durgical.com/en/pharmacology/trastuzumab/)

## Related conditions 6

- [Non-Hodgkin lymphoma](https://durgical.com/en/conditions/non-hodgkin-lymphoma/)
- [Chronic lymphocytic leukaemia](https://durgical.com/en/conditions/chronic-lymphocytic-leukaemia/)
- [Rheumatoid arthritis](https://durgical.com/en/conditions/rheumatoid-arthritis/)
- [Granulomatosis with polyangiitis](https://durgical.com/en/conditions/granulomatosis-with-polyangiitis/)
- [Microscopic polyangiitis](https://durgical.com/en/conditions/microscopic-polyangiitis/)
- [Pemphigus vulgaris](https://durgical.com/en/conditions/pemphigus-vulgaris/)

[← Back to the class: Antineoplastic monoclonal antibodies](https://durgical.com/en/pharmacology/classes/antineoplastic-monoclonal-antibodies/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Rituximab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a607038.html) (MedlinePlus (U.S. National Library of Medicine), 2022); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01FA01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/rituximab/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/rituximab/