[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/) › Ocrelizumab

# Ocrelizumab

## Multiple sclerosis disease-modifying therapies?

Multiple sclerosis disease-modifying therapies

An anti-CD20 antibody infused every 6 months that depletes B cells; used in relapsing and primary progressive multiple sclerosis.

Updated Nov 1, 2026

## Quick facts

**Group**
[Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/)

**Target**
CD20 on B lymphocytes

**Used for**
Relapsing forms of multiple sclerosis

**Key effects**
Infusion reactions · Swelling or pain in the hands

**Monitor**
Vital signs and symptoms during · Signs of infection

**ATC**
L04AG08

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

On this page

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

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

- Study Test yourself

- Connections Connections

## Mechanism of action

Ocrelizumab is a humanized monoclonal antibody against CD20, a surface protein of mature B lymphocytes. Binding leads to depletion of circulating B cells. In multiple sclerosis, B cells act as antigen-presenting cells that drive the immune attack on myelin, not only as antibody producers; removing them reduces relapses and slows progression.

- Ocrelizumab binds CD20 on B cells
- Circulating B cells are depleted
- Less antigen presentation to myelin-reactive T cells
- Fewer relapses and slower disability

## Indications

- Relapsing forms of multiple sclerosis [Multiple sclerosis →](https://durgical.com/en/conditions/multiple-sclerosis/)
- Primary progressive multiple sclerosis [Multiple sclerosis →](https://durgical.com/en/conditions/multiple-sclerosis/)

## Adverse effects

### Common

- Infusion reactions (itching, rash, throat irritation, flushing, fever, headache, fast heartbeat)
- Swelling or pain in the hands, arms, legs or feet

### Serious (rare, important)

- Serious infusion reactions, during or up to a day after the infusion
- Serious infections, including herpes zoster, genital or skin infections; PML
- Hepatitis B reactivation
- Bowel problems: diarrhoea, bloody or black stools, abdominal pain
- Possible higher risk of some cancers, including breast cancer

## Contraindications

- Active hepatitis B infection
- Allergy to ocrelizumab

## Key interactions

**Vaccines**
Some are given at least 4 weeks and others at least 2 weeks before starting; during treatment vaccines are given only with the doctor's approval

## What is monitored

- Hepatitis B screening before the first infusion
- Vital signs and symptoms during and for at least 1 hour after each infusion
- Signs of infection, new neurological symptoms and bowel symptoms
- Breast cancer screening as recommended

## Administration and safety

- Slow intravenous infusion by trained staff; premedication is often given to reduce reactions
- After a reaction the doctor may pause, stop or change the treatment
- Observation for at least 1 hour after the infusion

## Pregnancy and breastfeeding

Effective contraception is used during treatment and for 6 months after the last dose; a baby exposed in pregnancy may need some vaccines delayed.

## Nursing care

- Ask about infections, hepatitis B, inflammatory bowel disease and recent vaccines before each infusion
- Watch for rash, itching, throat swelling, breathing difficulty, fever and fast heartbeat during and after the infusion
- Teach to report reactions that start up to 24 hours later

## Pharmacokinetics

**Absorption**
Intravenous infusion

**Elimination**
Long-acting; given every 6 months after two initial infusions two weeks apart

## Memory aid

«OCRElizumab: Out goes CD20, Remove B cells Every six months»

## Test yourself

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

## What does ocrelizumab target?

CD20 on B lymphocytes.

## Which form of MS, besides relapsing MS, is ocrelizumab approved for?

Primary progressive multiple sclerosis.

## Which viral infection is screened for before the first infusion?

Hepatitis B.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/ocrelizumab/)

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

## Connections

## Related drugs 3

- [Natalizumab](https://durgical.com/en/pharmacology/natalizumab/)
- [Fingolimod](https://durgical.com/en/pharmacology/fingolimod/)
- [Methylprednisolone](https://durgical.com/en/pharmacology/methylprednisolone/)

## Related conditions 1

- [Multiple sclerosis](https://durgical.com/en/conditions/multiple-sclerosis/)

[← Back to the class: Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/)

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

Sources: [Ocrelizumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a617026.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L04AG) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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