Celecoxib (Celebrex) | Cancer Research UK
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Celecoxib (Celebrex)

This page tells you about the drug celecoxib and its possible side effects. There is information about


What celecoxib is

Celecoxib is one of a group of drugs called COX-2 inhibitors. It also has the brand name Celebrex. COX-2 inhibitors are a type of anti inflammatory drug. They block a protein called COX-2 that causes inflammation and pain. COX-2 inhibitors are used to control pain caused by some medical conditions such as arthritis.

There is some evidence that the enzyme COX-2 may also help cancers to grow. COX-2 blockers are sometimes used to try to prevent bowel cancer in people at high risk of developing it.

Clinical trials are looking at whether celecoxib can treat or prevent other types of cancer, including

  • Prostate cancer
  • Breast cancer
  • Bladder cancer

How you take celecoxib

Celecoxib is a capsule. You swallow it whole with a glass of water. You can take it with or without food.

As a painkiller you may take it once or twice a day. As a prevention or treatment for cancer you take it once a day. Try to take it at the same time each day.

It is very important that you take capsules according to the instructions your doctor or pharmacist gives you. For example, whether you have a full or empty stomach can affect how much of a drug gets into your bloodstream. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first.

We've listed the side effects associated with celecoxib below. You can use the links to find out more about each side effect. Where there is no link, please go to our cancer drug side effects section or use the search box at the top of the page.


Common side effects

More than 10 in every 100 people have a higher blood pressure than normal while taking celecoxib.


Occasional side effects

Between 1 and 10 in every 100 people have one or more of these.

  • Difficulty sleeping
  • Dizziness – don't drive or operate machinery if you have this
  • Shortness of breath, a cough, a blocked or runny nose, a sore throat
  • Diarrhoea – drink plenty of fluids if you have diarrhoea. Let your doctor or nurse know if it gets severe or lasts more than 3 days
  • Feeling and being sick – let your doctor or nurse know if you have this
  • Indigestion and wind
  • Difficulty swallowing
  • Skin changes, including a rash and itching
  • Flu like symptoms
  • Swelling of the legs due to fluid build up (known as peripheral oedema)
  • Infections – including urine and chest infections
  • If you have an allergy to something it may become worse
  • Heart problems – people who take celecoxib for 3 years or more have a higher than normal risk of angina, heart failure or a heart attack. Let your doctor or nurse know if you have any chest pain

Rare side effects

Fewer than 1 in 100 people have these

  • Changes in your blood chemistry – the levels of potassium may be higher than normal. You may not have any symptoms from this but you will have regular blood tests to check the levels
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Feeling very sad or depressed
  • Ringing in the ears (tinnitus) and loss of hearing
  • Blurred vision
  • A sore mouth
  • Irritation of the stomach, which can include bleeding – if you notice your bowel motions are black or you vomit blood contact your doctor or nurse straight away

Important points to remember

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on.

This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)
  • Other drugs you are having

Coping with side effects

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together.

Pregnancy and contraception

This drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment and for a few months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


Do not breastfeed during this treatment because the drug may come through in the breast milk.


Related information


More information about celecoxib

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at www.medicines.org.uk.

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at www.mhra.gov.uk.

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Updated: 4 August 2014