Corticosteroids - Side effects of corticosteroids

Hormones are powerful chemicals that affect many different processes in the body, from the strength of your bones to your weight. As corticosteroids are hormones, they can have a wide range of side effects.

If you are prescribed corticosteroids, any side effects and their severity will depend on three factors:

• the type of corticosteroid medicine you're taking – steroid tablets (oral corticosteroids) are more likely to cause side effects than inhalers or injections
• the strength of the dosage – the higher the dose, the greater the risk of developing side effects
• the length of time you are using it for – for example, it is highly likely you will develop more serious side effects if you take oral corticosteroids for more than three months or if you have three to four courses of treatment a year

Inhaled corticosteroids

If inhaled corticosteroids are taken for a short period, most people tolerate them well and have few or no side effects.

Long-term use to treat a condition such as asthma can cause oral thrush. This is a fungal infection that develops inside your mouth.

Rinsing your mouth out with water after using inhaled corticosteroids can help prevent oral thrush.

Injected corticosteroids

Corticosteroids 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. Over time, repeated steroid injections into a muscle can weaken it.

Corticosteroids are usually only injected directly into the blood when there is an urgent need for treatment. Corticosteroids injected into the blood can cause side effects including:

• stomach irritation, such as indigestion
• rapid heartbeat (tachycardia)
• nausea
• insomnia
• a metallic taste in the mouth

You may also experience mood changes. For example, you could go from feeling very happy one minute to being irritable, depressed or restless the next.

Oral corticosteroids

Side effects of oral corticosteroids used for longer than three weeks can include:

• weight gain
• acne – a skin condition that affects most people at some point
• mood changes, such as becoming aggressive, irritable and short tempered with people
• rapid mood swings
• thinning skin which can bruise easily
• muscle weakness
• a combination of fatty deposits that develop in the face (moon face), stretch marks across the body and acne – this is known as Cushing’s syndrome
• weakening of the bones (osteoporosis)
• the onset of diabetes, or worsening of existing diabetes
• high blood pressure
• glaucoma – an eye condition where fluid gathers inside the eye
• cataracts – an eye condition where cloudy patches develop at the front of the eye
• delayed wound healing
• reduced growth in children
• increased risk of infection

The risk of more serious side effects increases with higher dosages or longer courses of corticosteroids. These side effects should improve if you're able to reduce your dosage. 

However, osteoporosis can be a persistent problem, particularly if you are over 65. This can make you more vulnerable to breaking a bone.

Your GP can prescribe medication and calcium and vitamin D supplements, which help strengthen your bones and can compensate for the effects of prednisolone. Find out more information about treatment for osteoporosis.

You may also be referred for a type of X-ray called a dual energy X-ray absorptiometry (DEXA) scan. This can be used to assess how strong your bones are. You may require several DEXA scans during the course of your treatment. See diagnosing osteoporosis for more information.

Stomach ulcers can be another problem for people who take high doses of oral corticosteroids on a long-term basis. To protect against stomach ulcers, you may be prescribed a type of medication called a proton pump inhibitor (PPI). This reduces the amount of acid in your stomach, which will make you less vulnerable to developing stomach ulcers. Find out more about treating stomach ulcers.

You will also probably have regular checks and tests for conditions such as diabetes, high blood pressure and glaucoma if you need to take oral corticosteroids on a long-term basis.

Mental heath

About 1 person in 20 who takes the oral corticosteroid prednisolone experiences changes in their mental state. These changes may include:

• feeling depressed and suicidal
• feeling manic (very happy and full of energy and ideas)
• feeling very anxious
• feeling very confused
• hallucinations (seeing or hearing things that are not really there)
• having strange and frightening thoughts

If you experience any of these, contact your GP as soon as possible.

Vulnerability to infection

Oral corticosteroids will make you more vulnerable to infection, particularly the viruses that cause:

• chickenpox and shingles (the varicella-zoster virus)
• measles (caused by the paramyxovirus)

You may become very ill if you develop these viral infections, even if you have been previously infected.

Avoid close contact with anyone who has a chickenpox, shingles or measles infection.

Seek medical advice immediately if you think you have been exposed to an infection that causes chickenpox, shingles or measles or if a member of your household develops one of these infections.