[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Coagulation factor replacement and haemophilia agents](https://durgical.com/en/pharmacology/classes/coagulation-factor-replacement-and-haemophilia-agents/) › Emicizumab

[Pharmacology](https://durgical.com/en/pharmacology/) · [Coagulation factor replacement and haemophilia agents](https://durgical.com/en/pharmacology/classes/coagulation-factor-replacement-and-haemophilia-agents/)

# Emicizumab

A bispecific antibody that bridges factors IXa and X, doing factor VIII's job. Given under the skin to prevent bleeds in haemophilia A.

Updated 2026-11-01

- Class: [Coagulation factor replacement and haemophilia agents](https://durgical.com/en/pharmacology/classes/coagulation-factor-replacement-and-haemophilia-agents/)
- Target: Factor IXa and factor X (bridged by the antibody)
- ATC code: B02BX06
- WHO Model List of Essential Medicines

## Mechanism of action

Emicizumab is a bispecific antibody. One arm binds activated factor IX and the other binds factor X, placing them side by side so factor X is activated without factor VIII. It stands in for factor VIII's function rather than replacing the protein.

- One arm grabs factor IXa
- The other arm grabs factor X
- Factor X is activated without factor VIII

## Pharmacokinetics

**Absorption**
Given by subcutaneous injection

## Indications

- Haemophilia A, to prevent or reduce the frequency of bleeding episodes [Haemophilia A and B →](https://durgical.com/en/conditions/haemophilia-a-and-b/)

## Adverse effects

### Common

- Injection-site reactions
- Headache
- Joint pain

### Serious (rare, important)

- Thrombotic microangiopathy and thrombosis, especially with activated prothrombin complex concentrate for breakthrough bleeds

## Contraindications

- Hypersensitivity to emicizumab

## Key interactions

**Activated prothrombin complex concentrate (aPCC)**
Risk of thrombotic microangiopathy and thrombosis

**Laboratory clotting and inhibitor tests**
Standard methods can mislead; the laboratory must be told the patient uses emicizumab

## What is monitored

- Breakthrough bleeds and what was used to treat them
- Signs of thrombotic microangiopathy (confusion, low urine, jaundice)

## Administration and safety

- Subcutaneous injection; patients and caregivers can learn to give it at home
- It prevents bleeds but does not treat an acute bleed; a plan for breakthrough bleeds is agreed with the haematology team

## Nursing care

- Teach injection technique and site rotation
- Make sure the patient carries information that they receive emicizumab, for emergency teams and laboratories
- Warn about the danger of using aPCC without haematology advice

## Pregnancy and breastfeeding

There are no adequate data in pregnancy; women of childbearing age are advised to use contraception during treatment.

## Memory aid

EMIcizumab = «Eight Mimic»: it mimics factor VIII by bridging IXa and X.

## Test yourself

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

## How does emicizumab replace factor VIII's function?

It binds factor IXa and factor X at the same time, so X is activated.

## By which route is it given?

Subcutaneous injection, which patients can learn to give at home.

## Which combination can cause thrombotic microangiopathy?

Emicizumab with activated prothrombin complex concentrate.

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

## Related drugs

- [Coagulation factor VIII](https://durgical.com/en/pharmacology/coagulation-factor-viii/)

## Related conditions

- [Haemophilia A and B](https://durgical.com/en/conditions/haemophilia-a-and-b/)

[← Back to the class: Coagulation factor replacement and haemophilia agents](https://durgical.com/en/pharmacology/classes/coagulation-factor-replacement-and-haemophilia-agents/)

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

Sources: [Emicizumab-kxwh Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a622046.html) (MedlinePlus (U.S. National Library of Medicine), 2022); [Treatment of Hemophilia | Hemophilia | CDC](https://www.cdc.gov/hemophilia/treatment/index.html) (Centers for Disease Control and Prevention, 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=B02BX06) (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/emicizumab/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/emicizumab/