[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Interleukin inhibitors](https://durgical.com/en/pharmacology/classes/interleukin-inhibitors/) › Ustekinumab

[Pharmacology](https://durgical.com/en/pharmacology/) · [Interleukin inhibitors](https://durgical.com/en/pharmacology/classes/interleukin-inhibitors/)

# Ustekinumab

An antibody against p40, the piece shared by IL-12 and IL-23, for psoriasis, psoriatic arthritis, Crohn disease and ulcerative colitis.

Updated 2026-11-01

- Class: [Interleukin inhibitors](https://durgical.com/en/pharmacology/classes/interleukin-inhibitors/)
- Target: p40 subunit shared by interleukin-12 and interleukin-23
- ATC code: L04AC05
- WHO Model List of Essential Medicines

◆**p40 subunit shared by interleukin-12 and interleukin-23**Ustekinumab

ⓘ The figure shows IL-12 bound to the ustekinumab Fab at its p40 subunit.

**Target in 3D:** p40 subunit shared by interleukin-12 and interleukin-23. PDB structure 3HMX (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/3HMX) · Drag to rotate · pinch to zoom

## Mechanism of action

Ustekinumab is a human IgG1 monoclonal antibody against p40, the subunit common to IL-12 and IL-23. It stops both cytokines from binding their receptor chain IL-12Rβ1 on T cells and NK cells, which reduces Th1 responses (IL-12) and the Th17 axis (IL-23), the main drivers of psoriasis and inflammatory bowel disease.

- Antibody binds the p40 subunit
- IL-12 and IL-23 cannot reach their receptor
- Th1 and Th17 responses fall
- Skin and gut inflammation settles

## Pharmacokinetics

**Absorption**
Subcutaneous injection; an intravenous infusion is used for the first dose in bowel disease

**Metabolism**
Broken down like other antibodies

## Indications

- Plaque psoriasis [Psoriasis →](https://durgical.com/en/conditions/psoriasis/)
- Psoriatic arthritis [Psoriatic arthritis →](https://durgical.com/en/conditions/psoriatic-arthritis/)
- Crohn disease [Crohn disease →](https://durgical.com/en/conditions/crohn-disease/)
- Ulcerative colitis [Ulcerative colitis →](https://durgical.com/en/conditions/ulcerative-colitis/)

## Adverse effects

### Common

- Upper respiratory infections, runny nose
- Headache, tiredness
- Injection-site redness
- Nausea, vomiting, diarrhoea

### Serious (rare, important)

- Serious infections, including tuberculosis
- Posterior reversible encephalopathy: sudden severe headache, confusion, vision changes or seizures
- Severe allergic reactions
- Non-infectious pneumonia: persistent cough or shortness of breath
- Skin cancer and other cancers

## Contraindications

- Hypersensitivity to ustekinumab
- Active serious infection, including active tuberculosis

## Key interactions

**BCG vaccine**
Not given during treatment and for a year afterwards; recent BCG is reported before starting.

**Live vaccines**
Risk of infection from the vaccine strain; avoided during treatment, and vaccines are updated before starting.

## What is monitored

- Latent tuberculosis test before starting
- Signs of infection
- Skin checks for cancer
- New neurological symptoms (headache, confusion, seizures)

## Administration and safety

- Subcutaneous injection; the intravenous form is infused over at least an hour by staff.
- The first subcutaneous dose is given in the clinic.

## Nursing care

- Before the first dose, confirm the latent tuberculosis test (and hepatitis B screening where ordered) and that vaccines are up to date.
- Do not give the dose during an active infection; teach to report fever, cough, burning on urination or hot, red skin.
- Live vaccines are avoided during treatment; any vaccine is discussed with the team first.
- Ask about BCG vaccination in the past year and about allergy shots (immunotherapy).
- Teach to report sudden severe headache, confusion or vision changes at once.

## Pregnancy and breastfeeding

Human data are limited; the treating team weighs benefits and risks, and the baby's doctor is told before live vaccines.

## Memory aid

UStekinumab: 12 + 23 share one piece (p40) — hit it once, block both.

## Test yourself

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

## Why does a single antibody block both IL-12 and IL-23?

Ustekinumab binds p40, a subunit present in both cytokines.

## Which vaccine is specifically avoided during ustekinumab treatment and for a year after?

BCG (and live vaccines in general).

## Which rare neurological syndrome is a warning with ustekinumab?

Posterior reversible encephalopathy syndrome: sudden headache, confusion, seizures, vision changes.

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

## Related drugs

- [Secukinumab](https://durgical.com/en/pharmacology/secukinumab/)
- [Adalimumab](https://durgical.com/en/pharmacology/adalimumab/)
- [Infliximab](https://durgical.com/en/pharmacology/infliximab/)

## Related conditions

- [Psoriasis](https://durgical.com/en/conditions/psoriasis/)
- [Psoriatic arthritis](https://durgical.com/en/conditions/psoriatic-arthritis/)
- [Crohn disease](https://durgical.com/en/conditions/crohn-disease/)
- [Ulcerative colitis](https://durgical.com/en/conditions/ulcerative-colitis/)

[← Back to the class: Interleukin inhibitors](https://durgical.com/en/pharmacology/classes/interleukin-inhibitors/)

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

Sources: [Ustekinumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a611013.html) (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 39 (McGraw Hill, 2023); [Altered Immunocompetence | Vaccines & Immunizations | CDC](https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/immunocompetence.html) (Centers for Disease Control and Prevention (CDC), 2024); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L04AC05) (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/ustekinumab/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/ustekinumab/