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What is an immunosuppressant?

Published on February 10, 2022 at 15:50 / Updated on February 10, 2022 at 17:48

Have you ever been asked, during a medical questionnaire for example, if you were taking an immunosuppressant? At that time, you may have wondered why such a drug is used, and most importantly, whether your medicines have such an effect. You’re not alone!

The immune system

To understand what an immunosuppressant is, you must first know the basics of the immune system. The immune system enables the human body to defend itself against infection and disease. It uses different methods and barriers (beginning with the skin) to defend us against different bacteria, viruses, parasites, etc.  

Several cells and organs are involved in defending the human body. Most of the work is done by the white blood cells, which are found in the blood, and that are produced by the bone marrow.

How does the immune system work?

The immune system detects antigens on bacteria, viruses, or other invaders foreign to the human body. When it perceives antigens as being dangerous for the body, it triggers an immune response to protect it.

This is when antibodies produced by the white blood cells are sent to the detected antigens to neutralize the possible invader. The immune system then remembers the antigens it has faced and will be more effective if it encounters the same invaders in the future!

This is also how vaccines work to strengthen the immune system against certain diseases.

Autoimmune response

Most of the time, the immune system is able to correctly identify invaders and trigger immune responses only against dangerous cells or cells that do not come from its body, such as viruses.

Unfortunately, it can happen that the immune system detects one of our own cells as being dangerous. The body can then trigger an immune response and attack its own cells. This is called an autoimmune response.

Osteoarthritis is a good example of autoimmune disease; the body attacks its own cells and damages the joints.

An autoimmune response can also occur during a transplant. For example, the immune system of a person receiving a kidney transplant might detect it as foreign and activate an immune response to get rid of it. Obviously, we want to avoid this type of reaction!

Immunosuppressive medications

This is when immunosuppressive medications come into play.

When the body isn’t using its immune system properly, calming it down is necessary. Immunosuppressants will suppress the immune system’s ability to respond. They can be used to reduce an excessive immune response or to prevent an immune response launched against our own cells or a transplanted organ.

Different types of immunosuppressive medications can be used, for the short or long term, depending on the situation.

Side effects

By now, you can understand that immunosuppressive medications can be very useful! 

They help patients live a more normal life despite their autoimmune disease, and others to be able to live longer by facilitating organ transplants.

However, these benefits are not achieved without compromise, as immunosuppressive medications can, unfortunately, cause several side effects.

The most common side effect of this class of drugs is the risk of infection. Although immunosuppressants target harmful immune responses in the human body as much as possible, they can also decrease the immune system’s overall effectiveness.

By decreasing the body's level of defense, we are unfortunately more at risk of infections by bacteria or viruses. 

This is also why some immunosuppressed people must receive more doses of certain vaccines; they need a bigger boost in order to defend themselves against a particular infection.

Risks versus benefits

It’s important to discuss with your healthcare professional to ensure that the benefits of immunosuppressive therapy outweigh the risks for your particular condition. They can also inform you about the various side effects and help you to continue the treatment.


As their defense system isn’t at full capacity, people taking immunosuppressive medications should be vigilant and comply with various hygiene measures to limit the risk of infection.

It may be worth notifying your loved ones that you’re taking these medications so that they too pay special attention! Simple things like frequent handwashing can make a big difference.

If you have more specific questions about your condition or your treatment, don't hesitate to talk to your healthcare professional!

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