Corticosteroids are powerful medications that can sometimes have a wide range of side effects.
They will only be used if the potential benefits are thought to outweigh this risk.
The risk of experiencing side effects largely depends on:
- the type of steroid you're taking – steroid tablets (oral corticosteroids) are more likely to cause side effects than inhalers or injections
- the dose – the higher the dose, the greater the risk of developing side effects
- the length of treatment – for example, you're more likely to develop side effects if you take steroid tablets for more than three weeks
- your age – young children and the elderly are more likely to experience side effects
Some of the main side effects are listed below, but this is not a complete list. To learn about all the possible side effects of your medication, read the patient information leaflet that comes with it.
Inhaled steroids usually have few or no side effects if used at normal doses. However, they can sometimes cause:
Rinsing your mouth out with water after using your medication can help to prevent oral thrush, and using a device called a spacer with your medication can help to prevent many of the other problems.
There is also some evidence that steroid inhalers used by people with chronic obstructive pulmonary disease (COPD) can increase the risk of chest infections such as pneumonia. Discuss this with your health professional if you’re concerned.
Inhaled steroids at high doses can sometimes cause some of the more serious side effects that are more often linked with steroid tablets (see below), but this is rare.
Steroids that are injected into muscles and joints may cause some pain and swelling at the site of the injection. However, this should pass within a few days.
Steroid injections can also cause muscle or tendon weakness, so you may be advised to rest the treated area for a few days after the injection. Other possible side effects can include infections, blushing, and thinning and lightening of the skin in the area where the injection is given.
Because of the risk of side effects, steroid injections are often only given at intervals of at least 6 weeks and a maximum of 3 injections into one area is usually recommended.
Steroids that are injected into a blood vessel (intravenous steroids) may sometimes cause some of the more widespread side effects described below.
Short, occasional courses of steroid tablets taken for no longer than three weeks are very unlikely to cause troublesome side effects.
It’s sometimes necessary, however, for them to be taken for longer periods. In these cases, you’re more likely to develop troublesome side effects, although this is not inevitable.
Steroid tablets taken for longer than 3 weeks can potentially cause:
- increased appetite – which can potentially lead to weight gain if you find it difficult to control what you eat
- rapid mood swings and mood changes – such as becoming aggressive, irritable and short-tempered with people
- thin skin that bruises easily
- muscle weakness
- delayed wound healing
- a combination of fatty deposits that develop in the face, stretch marks across the body and acne – known as Cushing’s syndrome
- weakening of the bones (osteoporosis)
- diabetes (or they may worsen existing diabetes)
- high blood pressure
- glaucoma and cataracts (eye conditions)
- stomach ulcers – you may be prescribed an additional medication called a proton pump inhibitor (PPI) to reduce this risk
- mental health problems, such as depression, suicidal thoughts, anxiety, confusion and hallucinations – see your GP if you experience any of these problems
- increased risk of infections, particularly chickenpox, shingles and measles – avoid close contact with anyone who has an infection and seek medical advice immediately if you think you may have been exposed
- reduced growth in children
Most side effects should improve if you're able to reduce your dosage or eventually stop taking the medication.
You may have regular checks and tests for conditions such as diabetes, high blood pressure and glaucoma if you need to take steroid tablets on a long-term basis.