An immunosuppressive agent used in combination with cyclophosphamide and hydroxychloroquine in the treatment of rheumatoid arthritis. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), this substance has been listed as a known carcinogen. (Merck Index, 11th ed)

Synonyms: Imurel, Azathioprine Sulfate, 1H-Purine, 6-((1-methyl-4-nitro-1H-imidazol-5-yl)thio)-, Imuran, MRK240IY2L, Azothioprine, Azathioprine Sodium Salt, Immuran, 55372-48-0, 0, Azathioprine Sodium, Azathioprine, AM94R510MS, Sodium, Azathioprine