What is a steroid injection?

Some steroids occur naturally in the human body. Man-made steroids act like natural steroids to reduce inflammation. They're not the same as the steroids used by body builders to increase their muscle size and strength.

They can be taken as tablets or given as injections into the affected area (a 'local' injection). Steroid injections are often recommended for people with rheumatoid arthritis and other types of inflammatory arthritis.

They may also be recommended for osteoarthritis if your joints are very painful or if you need additional pain relief for a time. The injection should reduce inflammation, which in turn reduces pain.

A number of different steroids are available for injection. Short-acting soluble steroids can give relief within hours and should last for at least a week. The longer-acting, less soluble steroids may take around a week to become effective but can ease your symptoms for two months or longer.

How is it taken?

A GP, rheumatologist, orthopaedic surgeon, rheumatology nurse or physiotherapist will choose the most appropriate steroid mixture and dose for your condition and symptoms. They may want to check your blood pressure and blood sugar before your first injection as steroid injections can cause these to rise.

They might delay the injection if either is raised. Depending on where the pain and inflammation is, steroids can be injected:

  • directly into an inflamed joint (intra-articular injection)
  • into the soft tissues close to the joint (peri-articular injection)
  • into a muscle (intra-muscular injection).

Most injections are quick and easy to perform. An ultrasound scan, however, may be used to find exactly where the inflammation is so the steroid can be injected into a precise spot. However, many injections can be given without the need for ultrasound.

Sometimes you'll be given a local anaesthetic with the steroid to reduce the discomfort of the injection. If you do have a local anaesthetic, your pain should be relieved within minutes but it'll usually wear off within half an hour unless the anaesthetic selected is long acting. You may have some numbness from the anaesthetic which may last up to 24 hours.

You may want to arrange transport home after the injection, especially if you've had a local anaesthetic, because numbness from the anaesthetic can make it difficult to drive.

If you have an injection into a joint, you should rest it, or at least avoid strenuous exercise, for the first 1–2 days. It's also important, however, not to rest for too long. If you're having a course of physiotherapy, the physiotherapist may be keen to give more intensive mobilisation treatment after the injection, while your joint is less painful.

If the injection is very helpful, and other treatments are either unsuitable or less effective for you, it may be repeated if necessary. However, injections are often most useful in buying time while you and your doctor are finding the right medications to control your arthritis in the long term. Once your arthritis is well controlled the need for injections should be reduced.

How long does it take to work?

A number of different steroids are available for injection. Short-acting soluble steroids can give relief within hours and should last for at least a week. The longer-acting, less soluble steroids may take around a week to become effective but can ease your symptoms for two months or longer.

Side-effects and risks

Most people have steroid injections without any side-effects. They can be a little uncomfortable at the time of injection but many people find that they're not as bad as they had feared.

Occasionally people notice a flare-up in their joint pain within the first 24 hours after an injection. This usually settles by itself within a couple of days, but taking simple painkillers like paracetamol will help.

The risk of side-effects is greatest with the stronger mixtures. The mildest mixture is hydrocortisone. Methylprednisolone and triamcinolone are stronger and tend to be less soluble (dissolve less easily), so they stay in your joint for longer.

Injections can occasionally cause some thinning or changes in the colour of the skin at the injection site, particularly with stronger preparations. In very rare cases an injection of steroids into the muscle can lead to an indentation in the skin around the area.

Very rarely you may get an infection in the joint at the time of an injection. If your joint becomes more painful and hot you should see your doctor immediately, especially if you feel unwell.

People are often concerned about the possibility of other steroid-related side-effects such as weight gain. One of the advantages of steroid injections compared to tablets is that often the dose can be kept low. This means that these other side-effects are very rare unless injections are given frequently (more than a few times per year).

Other possible side-effects are facial flushing and temporary changes in women's periods and changes in mood – you may feel very high or very low.

Changes in mood may be more common in people with a previous history of mood disturbance. If you're worried please discuss this with your doctor.

It's also usual to see a rise in blood sugar levels for a few days after the injection if you have diabetes.

Effects on other treatments

You can take other medicines with steroid injections. However, if you're taking a drug that thins the blood (an anticoagulant) such as warfarin, you may need an extra blood test to make sure that your blood is not too thin to have the injection.

This is because of the risk of bleeding into the joint. You should mention that you take anticoagulants to the person giving the injection to make sure that they're aware. If you discuss this beforehand, you may be advised to adjust your warfarin dose before having the steroid injection.

Vaccinations

You can have vaccinations after you have had steroid injections.

Alcohol

There's no particular reason to avoid alcohol after steroid injections.

Fertility, pregnancy and breastfeeding

Current guidelines state that steroids are not harmful in pregnancy or breastfeeding so single steroid injections shouldn't affect fertility, pregnancy or breastfeeding and can be useful treatments in this situation.

If however, you're pregnant or breastfeeding you should discuss it with your doctor before having a steroid injection.