Hydrocortisone tablets are an oral corticosteroid medication that chemically mimics cortisol, a hormone naturally produced by the adrenal glands. The drug serves two primary therapeutic purposes: acting as a replacement hormone and functioning as a potent immunosuppressant. It is used to sustain life in patients with hormone deficiencies and to manage a wide range of inflammatory and autoimmune conditions. Understanding the difference between replacement therapy and pharmacological suppression is important.
Replacement Therapy for Adrenal Insufficiency
The primary use of hydrocortisone tablets is hormone replacement therapy for adrenal insufficiency, a condition where the body does not produce enough cortisol. This deficiency can stem from primary adrenal insufficiency (Addison’s disease), where the adrenal glands are damaged. Secondary or tertiary causes involve issues with the pituitary gland or hypothalamus, which fail to signal the adrenal glands to stimulate cortisol production.
In replacement therapy, the goal is to mimic the body’s natural cortisol release pattern, which peaks in the morning and tapers off toward the evening. Patients usually split the total daily dose into two or three doses, taking the largest dose upon waking to match the body’s circadian rhythm. A typical total daily dose ranges from 15 to 25 mg, but this is highly individualized.
A key component of this treatment is “stress dosing,” necessary to prevent a life-threatening adrenal crisis. During periods of physical stress, such as fever, infection, serious injury, or surgery, the body requires significantly more cortisol. Patients are instructed to temporarily double or triple their daily hydrocortisone dose to accommodate this increased demand. This adjustment is essential because the body relies entirely on the medication for its stress-response hormone.
Managing Severe Inflammation and Autoimmune Conditions
Hydrocortisone tablets are also used at higher, pharmacological doses to manage conditions characterized by severe inflammation and an overactive immune system. The purpose is to suppress the body’s inflammatory and immune responses, not to replace a missing hormone. Conditions treated include severe allergic reactions, inflammatory bowel diseases (Crohn’s disease and ulcerative colitis), and rheumatic disorders like rheumatoid arthritis.
The starting dosage is typically much higher than replacement doses, sometimes ranging from 20 to 240 mg per day. This higher dose achieves a powerful anti-inflammatory effect by dampening immune cell activity and blocking the release of inflammatory chemicals. Because of the potential for more pronounced side effects, treatment is often targeted for short-term use to control acute flare-ups.
Hydrocortisone can also treat severe skin conditions and certain types of cancer, helping reduce swelling and manage symptoms. Once the condition is controlled, the dosage is slowly reduced over time to prevent withdrawal symptoms and minimize the risk of long-term side effects.
Understanding the Mechanism of Action
Hydrocortisone is classified as a glucocorticoid, a steroid hormone that works by interacting with specific receptors found inside cells throughout the body. Once the molecule enters a cell, it binds to its glucocorticoid receptor, forming a complex that moves into the cell nucleus. Inside the nucleus, this complex attaches to specific DNA sequences, modulating the expression of various genes.
This gene modulation is the root of the drug’s dual effects, influencing both metabolism and immune function. For replacement therapy, it mimics natural cortisol by supporting normal metabolic processes, maintaining blood pressure, and regulating glucose levels. For anti-inflammatory purposes, the drug suppresses the production of pro-inflammatory substances like cytokines and interleukins. This dampening effect reduces the swelling, redness, and pain associated with inflammatory and autoimmune diseases.
The medication’s influence on the immune system involves inhibiting the activity of various immune cells, which slows the overall inflammatory cascade. This mechanism makes hydrocortisone an effective tool for quickly controlling runaway immune responses. However, it also explains why patients taking high doses may have a reduced ability to fight off infections.
Administration and Safety Considerations
Hydrocortisone tablets must be taken exactly as prescribed, and the timing of doses is important for replacement therapy to align with the body’s natural rhythm. Patients often take the tablets with food or milk to minimize stomach irritation. The initial dosage varies widely, depending on the condition being treated.
A significant safety concern, especially after prolonged or high-dose therapy, is the risk associated with abrupt cessation. External hydrocortisone suppresses the body’s natural cortisol production by the adrenal glands, a process known as HPA axis suppression. Suddenly stopping the medication can lead to a dangerous hormone deficiency, causing severe fatigue, joint pain, muscle weakness, and potentially an adrenal crisis.
To avoid this withdrawal reaction, a healthcare provider will reduce the dose gradually, allowing the body’s natural cortisol production to slowly recover. Long-term use, even at replacement doses, can lead to side effects such as weight gain, mood changes, increased appetite, and a higher risk of infections. Prolonged use at higher doses can also contribute to bone density loss (osteoporosis) and elevated blood sugar levels.