Immunosuppressive Drugs for Ulcerative Colitis

Medically Reviewed by Sabrina Felson, MD on June 06, 2024
5 min read

Immunosuppressants, also called immunomodulators, do just what their name says – they suppress, modulate, or tone down your immune system so it reacts less to things that normally kick it into gear. Your immune response is what turns on the inflammation process in your body. When you have ulcerative colitis (UC), that response can go into overdrive. When immunosuppressants turn the immune system down, they also turn inflammation down.

These drugs can be very effective in treating UC as well as Crohn’s disease, another inflammatory bowel disease. But they can take a few months to start working. Because of this wait time, your doctor may start them at the same time as some faster-acting treatments, such as steroids. Once they start working, they can help you get off the steroid treatment. They can also reduce the number of flare-ups you have and help you stay symptom-free longer.

Your doctor may suggest an immunosuppressant treatment if:

  • You aren’t responding to other treatments such as aminosalicylates, antibiotics, or corticosteroids, or you have severe side effects.
  • Your body has become dependent on steroids and you need to come off them.
  • You have perianal disease (disease around the anus) or a fistula (pathways that form in your intestines that normally aren’t there).
  • You’re taking a biologic and need to help it work better and keep your body from trying to fight it.

Doctors mainly prescribe immunosuppressants when other treatments haven’t kept your inflammation under control. They’re useful as maintenance therapy, meaning you’ve already reached remission and want to stay there.

They can also help make biologic drugs more effective. When you take a biologic, your body may want to fight against it. By slowing down your immune system, immunosuppressants make your body less likely to do that.

You may take only one immunosuppressant, or a combination of them.

  • Azathioprine (Azasan, Imuran) and 6-mercaptopurine(6-MP) (Purinethol, Purixan) were originally developed to help prevent the body from rejecting transplanted kidneys. They’re the most common immunosuppressant treatments for IBD. When you’re on these drugs, your doctor will want to watch you closely to check for side effects. You may need to have regular blood tests to check on the health of your liver, kidneys, bone marrow, and pancreas. You take azathioprine and mercaptopurine in pill form once a day. In some cases, doctors give azathioprine as a shot in a hospital. 6-MP also has a liquid form you take by mouth.
  • Cyclosporine (Gengraf, Neoral, Sandimmune) is the option doctors typically turn to when you haven’t responded to other medications. It’s a drug that doctors also use for preventing transplanted organ rejection and treating arthritis. It has some serious side effects, so your doctor will have you take it for only a short time. You take it as a capsule. If your UC doesn’t respond to steroids, your doctor may give it to you through an IV in a hospital, although this isn’t common. Your doctor may suggest cyclosporine as a way to avoid surgery for your UC.
  • Methotrexate (Rheumatrex) is an option doctors typically try only if other medications haven’t worked, or you have a bad reaction to other drugs. You take it once a week as a pill or shot. More often, doctors choose this for Crohn’s disease rather than UC. In recent clinical trials, researchers haven’t yet been able to tell if it works well enough to recommend it more commonly for UC.
  • Tacrolimus (Prograf) is more commonly used for Crohn’s disease, but your doctor may use it to treat severe UC until a slower-acting immunomodulator starts to work. You take it as a capsule, or as granules you mix into water.
  • Tofacitinib(Xeljanz) is a type of immunosuppressant called a Janus kinase inhibitor (JAK inhibitor). It works by blocking Janus kinase, which is an enzyme involved in turning on the inflammation process. Doctors also use it to treat certain types of arthritis. Tofacitinib is often a go-to when other UC therapies aren’t working. You can take it by mouth in tablet form. It also comes as a long-acting tablet and a liquid.

Three types of biologics that also help fight inflammation to manage UC are:

  • Anti-tumor necrosis factor (anti-TNF) agents: Adalimumab (Humira), golimumab (Simponi), and infliximab (Remicade). These drugs, called tumor necrosis factor (TNF) inhibitors, or biologics, work by neutralizing a protein your immune system produces. They are for people with severe ulcerative colitis who don't respond to or can't tolerate other treatments.
  • Integrin receptor antagonists (IRAs): Vedolizumab (Entyvio). This intravenous (IV) medication treats UC that has not responded to other treatments. It’s also given to people who are trying to avoid taking steroids.
  • Interleukin (IL) inhibitors: Ustekinumab (Stelara) was approved to treat UC in October 2019. It targets proteins interleukin-12 and interleukin-23 in particular to fight inflammation.


The side effects you get from your immunosuppressants will depend on the types and doses you take. High doses can cause serious side effects.

And since they turn your immune system down, you’re at a higher risk of infection. Most commonly, people can get:

Be sure to tell your doctor if you start to have any signs of infection, such as fever or chills.

In addition to infection, immunosuppressants also make you more prone to:

In 2019, the FDA issued a warning about 10-milligram doses of tofacitinib, saying that it could increase the risk of blood clots and even death, compared to patients who took 5-milligram doses.

Very rarely, people taking immunosuppressants can get non-Hodgkin’s lymphoma, a cancer of the lymph system.

You shouldn’t get any live vaccines while you’re on immunosuppressants or 3 weeks before starting them. After you stop them, you should wait 3-6 months before getting a live vaccine. If vaccines don’t use live viruses, they’re safe, and you should stay up to date on them, especially because you’re at a higher risk of infection.

If you’re pregnant, trying to get pregnant, or breastfeeding, your doctor may choose a different drug for you. Some immunosuppressants can cause birth defects and could be harmful to take during pregnancy or breastfeeding.