Steroid injections, or corticosteroids, are synthetic versions of hormones that the adrenal glands produce. They treat a wide range of conditions. Although they can be effective and fast-acting, they may have side effects.

Steroid injections reduce inflammation, lower immune responses, and help control other functions of the body.

These injections are different than anabolic steroids, which are testosterone analogs with limited medical uses. Many sporting bodies have banned anabolic steroids.

Although they can be effective, steroid injections are not suitable for everyone, and they do pose some risks, including potentially severe side effects.

In this article, we explore what conditions steroid injections treat and how they work. We also consider the risks and side effects and how to manage them.

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Image credit: Adrienne Bresnahan/Getty Images

Doctors may inject corticosteroids into:

  • joints, muscles, and the tissues around them
  • the area around the spine
  • the blood

Steroid injections into joints, muscles, and other soft tissues usually treat arthritis or injury at specific sites in the body.

Doctors will often inject steroids near the spine for pain relief.

Intravenous injections into the bloodstream treat serious inflammation throughout the body.

Doctors may use corticosteroid injections to treat a wide range of conditions, including:

Steroid injections for painful muscles and joints

One common use of steroid injections is to reduce pain and inflammation in and around joints — for example, in arthritis — and in muscles and soft tissues generally.

Doctors often inject hydrocortisone into joints that are painful and swollen because of injury or arthritis. Hydrocortisone also treats bursitis and muscle and tendon pain.

Other steroids that treat painful joints include triamcinolone and methylprednisolone.

Steroid injections for cancer

A doctor may prescribe steroids, sometimes by injection, for people with cancer. In some cases, they might do this to treat the cancer itself. In others, they will use steroids to try to reduce:

  • sickness, hopefully increasing appetite as a result
  • allergic reactions to other drugs
  • inflammation
  • the immune response — for example, after a bone marrow transplant

Steroid injections for MS

A doctor may use steroid injections to treat a person with MS who is experiencing a flare-up.

One common treatment course involves intravenous injections of methylprednisolone over 3–5 days. Alternatively, a doctor may prescribe the same medicine in tablet form.

Steroid injections into the spine

A doctor may sometimes inject corticosteroids into the epidural area that surrounds the spine. The conditions that these injections treat include pain in the arms, legs, and lower back that results from inflamed spinal nerves.

Bony spurs, herniated disks, and other conditions can cause inflamed spinal nerves.

Steroid injections for COVID-19

Intravenous corticosteroids and tablets, such as dexamethasone, now feature in the World Health Organization (WHO) guidelines for the treatment of severe and critical COVID-19.

The WHO updated the guidelines in September 2020 after a review of the available evidence.

The authors of the review concluded, “Administration of systemic corticosteroids, compared with usual care or placebo, was associated with lower 28-day all-cause mortality in critically ill patients with COVID-19.”

Coronavirus resources

For more advice on COVID-19 prevention and treatment, visit our coronavirus hub.

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As steroid injections treat such a wide variety of medical conditions, and because they work in a variety of ways and at a range of dosages and formulations, there is no standard timeline for them to start working.

For example, steroid injections into joints to treat conditions such as arthritis vary in how long they take to have an effect.

Short-acting soluble steroids can start to work within hours, whereas less soluble formulations may take a week to start working.

The effects of steroid injections on joints vary depending on the type. The effects of short-acting soluble steroids may only last for a week. However, those of longer-lasting, less soluble steroids may last for several months and sometimes up to a year.

When doctors give people steroid injections for arthritis, for example, they may use them alongside other drugs to modify the course of the disease and treat the symptoms.

The doctor will typically administer intravenous injections when someone has an acute flare-up to provide quick symptom relief before other treatments take over.

A person can receive hydrocortisone injections into the same joint up to four times a year. A higher frequency of injections can cause damage to the joint.

Doctors often prescribe one or two short courses of intravenous steroids before switching to treatment with oral steroids. There are limits to their use to reduce the risk of side effects.

For example, the United Kingdom’s National Health Service (NHS) advise that people with MS do not take steroids (either as injections or tablets) more than three times a year.

The possible side effects of steroid injections vary depending on their use.

Injections into joints, muscles, and the spine

People may experience the following side effects:

  • a couple of days of pain and swelling at the injection site
  • a flushed face
  • bruising at the injection site
  • dimpling of, or loss of color in, the skin at the injection site
  • raised blood sugar levels, which can be a particular issue for people with diabetes
  • an increase in blood pressure for a few days in people with high blood pressure

Another more serious potential side effect of steroid injections is infection.

A person who notices their joints becoming more painful or hot should seek medical advice.

Epidural injections

Epidural injections can cause severe headaches.

Anyone experiencing this particular side effect should seek medical advice.

Intravenous injections

Injections into the bloodstream may have a different set of side effects because they are less localized. These effects can include:

  • mood changes
  • increased appetite
  • sleeping difficulties

Other risks

One risk of corticosteroid injections is that they can reduce the body’s immune response to infections.

People who have had these injections and then have exposure to chickenpox, shingles, or measles should seek medical advice.

For the same reason, people with infections or who have had or are about to have some vaccinations may not be able to have steroid injections.

It is a good idea to discuss all these issues, as well as any underlying health conditions, with a doctor before treatment.

Steroid injections can provide fast-acting relief for a range of medical conditions and injuries.

The injections work by reducing inflammation and dampening down the immune response.

Steroid injections are not suitable for everyone, and they do have some risks and side effects. Therefore, it is important to discuss the best treatment plan with a doctor.