[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/) › Guselkumab

# Guselkumab

## Interleukin inhibitors?

Interleukin inhibitors

A human antibody against the p19 subunit of interleukin-23, injected for plaque psoriasis, psoriatic arthritis, Crohn's disease and ulcerative colitis.

Updated Nov 1, 2026

## Quick facts

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

**Target**
Interleukin-23, p19 subunit (IL-23p19)

**Used for**
Moderate to severe plaque psoriasis · Crohn's disease

**Key effects**
Headache · Injection-site reactions · Joint pain

**Monitor**
Latent tuberculosis test before starting

**ATC**
L04AC16

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

Guselkumab is a human IgG1 monoclonal antibody that binds the p19 subunit found only in interleukin-23. IL-23 keeps Th17 cells active; with it neutralised, less IL-17 and other inflammatory cytokines are made in the skin, joints and gut. Unlike ustekinumab, it spares IL-12, which shares only the p40 subunit.

- Antibody binds the p19 subunit of IL-23
- IL-23 can no longer sustain Th17 cells
- Less IL-17 and related cytokines
- Psoriasis plaques, joints and gut inflammation improve

## Indications

- Moderate to severe plaque psoriasis [Psoriasis →](https://durgical.com/en/conditions/psoriasis/)
- Psoriatic arthritis [Psoriatic arthritis →](https://durgical.com/en/conditions/psoriatic-arthritis/)
- Ulcerative colitis [Ulcerative colitis →](https://durgical.com/en/conditions/ulcerative-colitis/)
- Crohn's disease [Crohn disease →](https://durgical.com/en/conditions/crohn-disease/)

## Adverse effects

### Common

- Headache
- Injection-site reactions
- Joint pain
- Diarrhoea, nausea or abdominal pain

### Serious (rare, important)

- Serious infections, including tuberculosis
- Liver injury
- Severe allergic reactions

## Contraindications

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

## Key interactions

**Live vaccines**
Avoided during treatment; age-appropriate vaccines are given before starting.

**Other immunosuppressants and biologics**
Added infection risk.

## What is monitored

- Latent tuberculosis test before starting
- Liver tests and liver symptoms
- Signs of infection

## Administration and safety

- Injected under the skin; the patient or a caregiver can inject at home after teaching.
- Vaccines are brought up to date before starting.
- The dose is delayed during an active infection, after the team's review.

## Pregnancy and breastfeeding

Human data are limited; pregnancy and breastfeeding are discussed with the treating team.

## Nursing care

- Confirm the tuberculosis test before the first dose.
- Teach to report fever, chills, cough or painful urination.
- Teach to report yellow skin or eyes, dark urine or upper right abdominal pain.

## Pharmacokinetics

**Absorption**
Subcutaneous injection; an intravenous form also exists

**Metabolism**
Broken down like other antibodies

## Memory aid

GUSelkumab and riSANKizumab: 'p19 is for psoriasis' — they spare IL-12 by skipping p40.

## Test yourself

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

## Which subunit does guselkumab bind?

The p19 subunit, unique to interleukin-23.

## How does guselkumab differ from ustekinumab?

Ustekinumab binds p40, shared by IL-12 and IL-23; guselkumab binds p19 and blocks only IL-23.

## Which infection test is done before guselkumab?

A test for latent tuberculosis.

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

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

## Connections

## Related drugs 3

- [Risankizumab](https://durgical.com/en/pharmacology/risankizumab/)
- [Ustekinumab](https://durgical.com/en/pharmacology/ustekinumab/)
- [Secukinumab](https://durgical.com/en/pharmacology/secukinumab/)

## Related conditions 4

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

[← 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: [Guselkumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a617036.html) (MedlinePlus (U.S. National Library of Medicine), 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L04AC16) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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