What Are 6-MP and Azathioprine and What Are They Used For?

These drugs were originally made to treat certain forms of leukemia. They also affect the immune system, so they are effective in inflammatory conditions like IBD.

What Should I Know Before Taking 6-MP or Azathioprine?

  • 6-MP and azathioprine may be taken with food to reduce stomach irritation.
  • Do not take them with milk. Milk will inactivate the drugs.
  • If you feel nauseous, try eating some dry foods (toast, crackers).
  • Call your doctor if you have been exposed to chicken pox or shingles while taking these drugs.
  • People on 6-MP or azathioprine should not receive live viral vaccines.

What Are the Food and Drink Interactions?

Other than milk, there are no known interactions between these medicines and food and drinks.

Interactions with these drugs may happen with the following:

  • Sulfa drugs
  • Allopurinol
  • Methotrexate
  • Coumadin

Is It Safe to Take These Drugs for Long Periods of Time?

These drugs can be taken long term. 6-MP and azathioprine appear to increase the risk of lymphoma and non-melanoma skin cancer. However, even with this increase, the overall risk of these types of cancer is still very low. Long term use requires periodic bloodwork and evaluation by your doctor. It may take several months before the medicine starts working. Like any immunosuppressant, it can increase your risk of infections.

What Are the Side Effects?


  • Loss of appetite
  • Abdominal pain
  • Sore mouth/throat
  • Nausea
  • Fever


  • Pancreatitis
  • Joint pain
  • Bone marrow suppression
  • Liver injury

Rev. 11/2013

This document is intended to provide health related information so that you may be better informed. It is not a substitute for a doctor's medical advice and should not be relied upon for treatment for specific medical conditions Please read your prescription label for additional drug information.