In some cases, doctors also prescribe chemotherapy medications -- such as azathioprine (Imuran), cyclophosphamide (Cytoxan), or methotrexate. Chemo drugs are powerful medicines used to treat cancer. Churg-Strauss syndrome is not cancer, so you would probably take a lower dose than someone who has cancer. While you take these drugs, you will likely get blood tests often to check for any side effects.