Azathioprine is the only purine analog that is widely used for the management of systemic lupus erythematosus (SLE). For SLE patients without renal involvement, it is given to those patients who require a maintenance dose of 15 mg or higher of prednisone and for those who experience recurrent flares. Azathioprine in combination with steroids may be given to a large number of patients with lupus nephritis. It is also effective for patients with skin lesions, pneumonitis, thrombocytopenia or hemolytic anemia. Azathioprine may be used during pregnancy but not during lactation. It has not been shown to increase the risk for the development of malignancies among patients with SLE.