There is no cure for Crohn’s disease, so symptom relief comes in the form of remission. A variety of treatments are available that can help ease your symptoms. Immunomodulators are drugs that modify the body’s immune system.

For someone with Crohn’s, this can help reduce the swelling that causes so many symptoms.

Immunomodulators include drugs that are immunosuppressants and immunostimulants. Immunosuppressants inhibit the body’s immunity, but immunity suppression can also put the body at higher risk for other diseases.

Immunostimulants increase or “stimulate” the body’s immune system, which encourages the body to begin fighting illness.

There are various types of immunomodulators, each sold under its own brand name. Azathioprine, mercaptopurine, and methotrexate are the three main types.

Azathioprine is often used in people who receive an organ transplant to prevent the body from rejecting the new organ by suppressing the body’s immune system. It’s also used to treat rheumatoid arthritis, which is a condition where a person’s body attacks their own joints.

Although azathioprine hasn’t been shown to be effective for reducing short-term Crohn’s symptoms or achieving remission, it may reduce the need for steroid treatment. Research does show that azathioprine helps keep people in remission once Crohn’s symptoms are under control.

For this reason, the American College of Gastroenterology supports using azathioprine for people who are in remission or who still have symptoms despite using steroids.

There are also some rare, but severe, side effects of azathioprine. This drug causes your body to produce fewer white blood cells. This can cause problems because white blood cells fight infection.

People taking azathioprine may also experience an inflammation of the pancreas or a higher risk of developing lymphoma.

Because of these side effects, azathioprine is usually only prescribed for moderate to severe cases of Crohn's. You should consider all of the risks before taking azathioprine. You may also be tested for TPMT deficiency, which can affect your immune system.

Mercaptopurine, also called 6-MP, is known to stop cancer cells from growing. This drug is often used to treat leukemia. In people with Crohn’s, mercaptopurine can help maintain remission.

Mercaptopurine can reduce the production of white and red blood cells. Your physician will likely want to conduct regular blood tests to ensure there is no damage to your bone marrow. You may also be tested for TPMT deficiency, which can affect your immune system.

Other side effects of mercaptopurine can include:

  • mouth sores
  • fever
  • sore throat
  • blood in the urine or stool

You should consider all possible side effects before you start treatment.

Methotrexate blocks cell metabolism, which causes cells to die. This has led to its use for Crohn’s disease, cancer, and psoriasis.

The American College of Gastroenterology supports using methotrexate to treat symptoms of Crohn’s disease in people who are dependent on steroids. Methotrexate also helps keep people with Crohn’s in remission.

However, methotrexate has side effects that include possible toxicity of the liver or bone marrow and, in rare cases, toxicity of the lungs. Men or women attempting to get pregnant shouldn’t use this drug. Less severe side effects include:

  • headache
  • drowsiness
  • skin rash
  • nausea and vomiting
  • hair loss

Immunomodulators can help combat symptoms related to Crohn’s disease, but they interfere with your body’s ability to fight infection. While taking immunomodulators, pay attention to any signs of infection, such as fever or chills.

If you develop these symptoms, contact your doctor immediately.

Any time you are taking immunomodulators, be sure your doctor is testing your blood regularly for signs of damage to your bones and internal organs.

Some immunomodulators may be fine to take during pregnancy, but you will need to discuss the pros and cons of starting a new medication with your doctor first. You should talk to your doctor if you’re pregnant or, whether you’re a man or woman, may be conceiving.