Corticosteroids, more often known as steroids, are an anti-inflammatory medicine prescribed for a wide range of conditions.

Corticosteroids are available in different forms including:

  • tablets (oral steroids)
  • injections - which can be into blood vessels, joints or muscles
  • inhalers, such as mouth or nasal sprays
  • lotions, gels or creams (topical steroids)

This section is about oral, inhaled and injected corticosteroids.

Read more about topical corticosteroids (steroid lotions, gels and creams).

What are corticosteroids used for?

Corticosteroids are mainly used to relieve inflammation. Inflammation occurs when the immune system (the body’s natural defence against infection and illness) causes part of the body to become swollen, red and filled with fluid in response to an infection.

Inflammation is helpful in preventing the spread of infection. However, in some health conditions the immune system triggers inflammation even though no infection is present. These are known as autoimmune conditions and include:

  • rheumatoid arthritis – where the immune system causes the joints to become inflamed
  • lupus – where inflammation can occur in both the joints and the skin

Sometimes, the immune system reacts to harmless substances (such as pollen), which happens when people have allergic conditions such as asthma.

Inflammation is potentially dangerous if it occurs in the lungs or airways. Corticosteroids are routinely used to treat severe flare-ups of asthma and chronic obstructive pulmonary disease (COPD).

Read more about the uses of corticosteroids and how corticosteroids work.

Side effects

Corticosteroid tablets can cause troublesome side effects if they are taken on a long-term basis. Therefore, they are usually only recommended when a person has a particularly severe flare-up of symptoms.

However, in some circumstances, a long-term course of corticosteroid tablets is the only effective form of treatment. If they are taken for more than three weeks, corticosteroid tablets can cause a range of side effects such as:

  • increased appetite that often leads to weight gain
  • acne – a long-term skin condition that affects most people at some point
  • stomach ulcer – an open sore that can develop on the inside lining of the stomach (a gastric ulcer) or in the small intestine (a duodenal ulcer)
  • muscle weakness
  • increased risk of infection

A particular concern for people who take corticosteroid tablets over a prolonged period is that they can have an increased risk of developing:

  • diabetes – a long-term condition caused by too much glucose (sugar) in the blood
  • high blood pressure 
  • osteoporosis – weak and brittle bones, which particularly affects people who are 65 or over

Read more about the side effects of corticosteroids.

Corticosteroids can also interact with some other types of medicine, which may alter their effect.

Read more about how corticosteroids interact with other medications.

Pregnancy and breastfeeding

Corticosteroids are generally safe to use in pregnancy. However, they are not usually recommended unless the potential benefits of treatment outweigh any risk to the baby.

For example, oral corticosteroids may be recommended because some conditions, such as severe asthma, may pose a bigger risk than the medication itself.

If oral corticosteroids are required during breastfeeding, prednisolone is usually recommended. This is because it is thought to have the least chance of causing the baby any adverse effects. However, as a precaution, it is recommended you wait for three to four hours after taking a tablet before feeding your baby.

Corticosteroid injections, inhalers or sprays are not thought to pose a threat to babies being breastfed. However, as a precaution, they should only be used if the benefits to the mother outweigh any potential risk.

Read more about who can use corticosteroids.

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