What are the side effects of treatment?

Because the treatment drugs suppress the immune system, there is an increased risk of developing serious infections. Prednisone can also cause weight gain, cataracts, brittle bones, high blood pressure, diabetes, and changes in mood and personality. Cyclophosphamide can cause sterility, bladder irritation, and bleeding, and even cancer of the bladder. Methotrexate can cause liver irritation. Cyclophosphamide and methotrexate can each cause changes in blood counts and sometimes lung inflammation.

Because the medicines used to treat Wegener's granulomatosis can have serious side effects, patients are monitored closely by their doctor. The dosage of medicine is adjusted as needed throughout the course of treatment.