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Tocilizumab to treat coronavirus (COVID-19)


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What is tocilizumab and why do we use it for coronavirus?

Coronavirus pneumonia is often associated with lots of inflammation which is caused by your immune system. Tocilizumab is an immune-suppressing medication, which is often used to treat rheumatoid arthritis. Clinical trials have shown that one dose of tocilizumab can reduce inflammation in patients who are severely unwell with coronavirus. It is mainly given to patients who are in intensive care, but can be given to patients who are on regular wards. 

Interleukin-6 (IL-6) is a protein in your blood that drives your immune response to coronavirus. Tocilizumab blocks this protein. Clinical trials show that tocilizumab can reduce the time you spend in hospital, and improve outcomes for patients who have been critically unwell with severe coronavirus.

What are the side effects?

Side effects can happen for up to 3 months after your dose of tocilizumab. Common side effects include colds, stomach pain, mouth ulcers, rashes, headache, dizziness, high blood pressure, headache, cough and breathlessness.

Uncommon side effects include inflammation of the lower bowel (diverticulitis), and inflammation of the stomach (gastritis). If you develop pain in your abdomen (tummy), especially if you are passing blood in your stool (poo), or have a fever (high temperature), you should seek medical attention. Some side effects are mentioned in more detail below.  


Because this drug affects your immune system, you might be more likely to get infections, and your body might not fight infection so well. If you become unwell or think you are getting an infection, contact your GP or NHS 111 for advice. You must tell any healthcare professionals looking after that you have had tocilizumab, and when you had it. It is important because you might not show the usual signs of an infection (for example, you might not have a fever).

Signs of infection include:

  • fever or chills                                                            
  • severe weakness or tiredness (fatigue)                                        
  • sore throat                                                                
  • burning or stinging when passing urine (pee)
  • persistent cough
  • difficulty breathing
  • new rashes or skin blisters
  • diarrhoea.


Most people who have an allergic reaction to tocilizumab will have it within 24 hours of their treatment. But, sometimes allergic reactions are delayed.

Signs of an allergic reaction include:

  • itchy rash or hives
  • difficulty breathing
  • vomiting (being sick) and stomach pain
  • swelling of the mouth, tongue or face
  • fainting
  • chest tightness or chest pain.

Hepatotoxicity (liver damage)

Tocilizumab can cause liver damage. While you are in hospital we check for this by doing blood tests. Once you have gone home, if you notice a yellowing of your skin or eyes, if your urine becomes very dark, or if you become tired and confused, you should speak to your GP, NHS 111 or go to your nearest Emergency Department (A&E) for assessment.


You should not receive any live vaccines (such as MMR or yellow fever) for 3 months after your treatment. You can still have your flu and coronavirus vaccinations.


If you are a woman of child bearing age, you should avoid getting pregnant for 3 months after receiving tocilizumab.


Ref number: 5137/VER1

Date published: March 2021 | Review date: March 2024

© 2021 Guy’s and St Thomas’ NHS Foundation Trust

A list of sources is available on request


Where next?

Contact us

If you have questions about taking tocilizumab, that are not answered on the NHS website, please contact the team who looked after you (details on your discharge letter).  

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