Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Your body converts azathioprine into mercaptopurine.
What might happen:
The amount of mercaptopurine in your body will increase and cause serious side effects.
What you should do about this interaction:
Make sure your healthcare professionals (e.g. doctor or pharmacist) know right away that you are taking these medicines together. Let your doctor know right away if you develop any signs of an infection (such as a fever, chills, or persistent sore throat), unusual bleeding or bruising (such as black or tarry stool, blood in your urine), mouth or lip sores, unusual tiredness, dizziness, weakness, chest pain, or shortness of breath.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Imuran (azathioprine) US prescribing information. Prometheus Laboratories Inc. February, 2014.
2.ISMP. Duplication with azathioprine and mercaptopurine. Medication Safety Alert June 29, 2006.