Temozolomide is used to treat specific types of brain cancer (eg, glioblastoma multiforme, anaplastic astrocytoma) in patients whose tumors have returned or whose tumors have just been diagnosed. It belongs to the group of medicines known as antineoplastics (cancer medicines).Temozolomide interferes with the growth of cancer cells, which are then destroyed by the body. Since the growth of normal body cells may also be affected by temozolomide, other side effects may occur. Some of these may be serious and must be reported to your doctor. Some side effects may not occur for months or years after the medicine is used.