Hi, Thanks for posting in HCM. I understand your concern. Azathioprine is an immunosuppressive drug, which belongs to the chemical class of purine analogues. It is an anti-metabolite and works by decreasing the effects of certain cells in the body s immune system. It is used in organ transplantation to prevent transplant rejection and in autoimmune diseases. Commonly reported side effects by use of azathioprine include: infection, nausea, leukopenia (decreased WBC count) and vomiting. Since it is known to decrease immunity, the individuals taking it are more prone for infections. When they are contacted with infections, it is essential to detect it at an earlier stage and treat appropriately so as to prevent further complications. Kindly take the medications as prescribed by your doctor and do the necessary follow-up accordingly. Hope the information provided would be helpful. All the best.