Immunosuppressive Drugs

Immunosuppressant drugs suppress actions of the immune system and its inflammatory response. These drugs are useful for very active IBD that does not respond to standard therapy and help maintain remission. An immunosuppressant is often combined with a steroid to speed up response during active disease. The steroid dose is usually lower than required by itself and can be withdrawn more quickly.

The immunosuppressants used in IBD are azathioprine (Imuran), mercaptopurine (6-MP, Purinethol), methotrexate, and cyclosporine (Neoral, Sandimmune). Patients on immunosuppresive drugs require regular blood tests to monitor for potential adverse effects.

Azathioprine is a prodrug of mercaptopurine. These agents are the preferred drugs for maintenance therapy of Crohn's disease and for active severe disease that does not respond to steroids. Rare but serious side effects include: pancreatitis, hepatitis, and bone marrow suppression.

Methotrexate is an effective alternative for patients with Crohn's disease who have failed other treatments and cannot tolerate other immunosuppressants. Its use is limited by its uncommon but serious side effects such as liver damage and lung inflammation.

Cyclosporine, given intravenously, is useful for severe active Crohn's disease patients that do not benefit form other therapies. Relapses and side effects occur commonly with cyclosporine when patients are switched to the oral form. Thus, it is not useful in long-term maintenance therapy.