Tocilizumab !

An antibody against the IL-6 receptor, given by infusion or injection, for rheumatoid arthritis, giant cell arteritis and cytokine release syndrome.

Updated 2026-11-01

Class: Interleukin inhibitors
Receptor: Interleukin-6 receptor (IL-6R), soluble and membrane-bound
ATC code: L04AC07

Interleukin-6 receptor (IL-6R), soluble and membrane-boundTocilizumab

The figure shows the IL-6 receptor bound to the tocilizumab Fab (cryo-electron microscopy).

Target in 3D: Interleukin-6 receptor (IL-6R), soluble and membrane-bound. PDB structure 8J6F (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Tocilizumab is a humanised IgG1 monoclonal antibody that binds both the soluble and the membrane form of the IL-6 receptor. IL-6 can then no longer signal through gp130 and JAK-STAT, so hepatic acute-phase proteins, fever, B-cell and T-cell activation and joint inflammation fall.

Antibody binds the IL-6 receptor
IL-6 cannot signal through gp130 and JAK-STAT
Less acute-phase response and fever
Joint and vessel inflammation settles

Pharmacokinetics

Absorption: Intravenous infusion or subcutaneous injection
Metabolism: Broken down like other antibodies

Indications

Rheumatoid arthritis Rheumatoid arthritis →
Giant cell arteritis Giant cell arteritis →
Polyarticular and systemic juvenile idiopathic arthritis Juvenile idiopathic arthritis →
Interstitial lung disease of systemic sclerosis Systemic sclerosis (scleroderma, including CREST) →
Cytokine release syndrome
COVID-19 in hospitalised adults who need oxygen or a ventilator COVID-19 →

Adverse effects

Common

Headache
Runny nose, sneezing
Injection-site reactions
Constipation or diarrhoea

Contraindications

Hypersensitivity to tocilizumab
Active serious infection

Key interactions

Other biologic immunosuppressants (TNF inhibitors, abatacept, anakinra): Added immunosuppression and infection risk.
Live vaccines: Risk of infection from the vaccine strain; avoided during treatment, and vaccines are updated before starting.

What is monitored

Latent tuberculosis and hepatitis B before starting
Neutrophils, platelets and liver tests
Lipids
Abdominal pain with fever or change in bowel habit

Administration and safety

Intravenous infusion in a clinic, or subcutaneous injection; the two forms are different products.
Vaccines are brought up to date before starting, where possible.

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 diverticulitis or bowel ulcers; report new abdominal pain with fever.
Teach to report yellow skin or eyes, dark urine or right upper abdominal pain.

Pregnancy and breastfeeding

Human data are limited; the treating team weighs benefits and risks.

Test yourself

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

What does tocilizumab bind?

The interleukin-6 receptor (soluble and membrane), not IL-6 itself.

Which gastrointestinal complication is a warning with tocilizumab?

Bowel perforation, especially in people with diverticulitis.

Which vasculitis is treated with tocilizumab?

Giant cell arteritis.

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

Sources: Tocilizumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 39 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.