Temozolomide Capsules 100mg is an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug. It is classified as an "alkylating agent." Temozolomide is used to treat certain types of brain tumors (glioblastoma). It works by slowing or stopping the growth of cancer cells. Temozolomide is usually given after other cancer medications have been tried without successful treatment of the cancer.