Cortisol is a hormone your adrenal glands make every day. It regulates inflammation, immune response, blood sugar, and blood pressure. Corticosteroid drugs mimic it, and they are among the most powerful anti-inflammatory agents available. Prednisone, dexamethasone, and hydrocortisone are common examples.

They work by entering cells and changing gene expression. They turn down the production of inflammatory proteins and turn up anti-inflammatory ones. That broad action makes them useful for asthma, rheumatoid arthritis, lupus, severe allergies, and many other conditions. They can be given orally, injected, inhaled, or applied topically. The route changes the side effect profile. Inhaled steroids for asthma act mostly in the lungs and have fewer systemic effects. Oral steroids taken for months can cause weight gain, bone loss, high blood sugar, cataracts, and immune suppression.

Key points:

• Short courses. Often safe and effective for acute flares.
• Long-term use. Requires monitoring for bone density, blood sugar, and blood pressure.
• Tapering. Stopping suddenly after long-term use can cause adrenal crisis.
• Not for everyone. Active infections and some eye conditions are contraindications.

Steroid-sparing drugs and biologics have reduced the need for long-term corticosteroids in many autoimmune conditions.