Mercaptopurine can cause the white cell count to go down. It is an immunosuppressant, meaning that is its intended purpose. Sometimes it can cause the WBC count to go too low. That is why the doctor told you to stop it. Usually the WBC count returns to within the normal range fairly quickly.
I had this happen when I was first put on Imuran, a cousin of Mercaptopurine. My WBC count was 2.1 and it returned to the normal range in a week. I was able to resume the medication and had no further incidents of low WBCs.
Moderator Crohn's disease, Osteoarthritis and Irritable Bowel Forums
CD, Ankylosing Spondylitis, small fiber peripheral neuropathy, avascular necrosis, peripheral artery disease, pulmonary hypertension, degenerative disc disease, asthma, severe allergy and a host of other medical problems.