Oral systemic corticosteroid that acts upon the hypothalamic/pituitary/adrenal system to help prevent inflammation. Essentially, this steroid suppresses the immunological response asthmatics' lungs have toward various triggers and stimuli. It is a powerful drug, with strong side effects when used long-term. Short-term bursts (10 days or less) are generally deemed safe, provided they are not administered too frequently. Common trade names are listed here.