Azathioprine Disease Interactions

Azathioprine may cause severe leukopenia, thrombocytopenia, macrocytic anemia, severe bone marrow depression and, rarely, pure red cell aplasia. Therapy with azathioprine should be administered cautiously in patients with bone marrow depression. Hematological toxicities are dose related. Caution and routine monitoring of blood counts and platelets is recommended. Patients should report any unusual bleeding or bruising.

Serious infections, including reactivation of latent infections have been reported with the use of azathioprine. Cases of JC virus-associated infection resulting in progressive multifocal leukoencephalopathy (PML), sometimes fatal, have been reported in patients treated with immunosuppressants, including azathioprine. A diagnosis of PML should be considered in any patient presenting with new-onset neurological manifestations and a consultation with a neurologist is recommended. Consider reducing the amount of immunosuppression in patients who develop PML, and in transplant patients, consider the risk that the reduced immunosuppression represents to the graft.

Azathioprine may accumulate in patients with impaired renal function. Therapy with azathioprine should be administered cautiously and may need dosage reduction in patients with impaired renal function.

Azathioprine is metabolically converted to the pharmacologically active 6-mercaptopurine (6-MP). Conversion to 6-MP and metabolism of 6-MP may be impaired in patients with liver disease. Therapy with azathioprine should be administered cautiously in patients with liver disease. Monitoring liver function is recommended in these patients.