Hydrocortisone
Hydrocortisone is synthetic cortisol — the body's own primary glucocorticoid — used as physiologic replacement in adrenal insufficiency and as a low-potency anti-inflammatory. Because it is identical to endogenous cortisol it has notable mineralocorticoid (salt-retaining) activity and a short duration, making it the preferred drug for mimicking the natural cortisol rhythm. Weaker per milligram than the synthetics, but the same catabolic trade-off at supraphysiologic doses.
01 Overview
Hydrocortisone is the reference glucocorticoid: 20 mg approximates the normal daily cortisol output, and replacement in Addison's disease and secondary adrenal insufficiency is dosed to mimic the diurnal rhythm (larger morning dose, smaller later). It is also used topically at low potency for mild skin inflammation and as stress-dose cover during illness or surgery in adrenally insufficient patients.
Because it has meaningful mineralocorticoid activity it can cause fluid retention and hypertension at higher doses. At physiologic replacement doses it is not catabolic; the muscle-wasting, immunosuppressive and HPA-suppressive effects appear only at supraphysiologic anti-inflammatory doses, as with any glucocorticoid. WADA restricts systemic administration in-competition.
02 Mechanism
Synthetic cortisol; activates glucocorticoid (and to a meaningful degree mineralocorticoid) receptors, providing physiologic replacement or, at higher doses, anti-inflammatory action.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Topical (OTC low) | 0.5–1 % | Transdermal | Low-potency OTC cream for minor skin inflammation. |
| Replacement | 15–25 mg/day | Oral | Split to mimic diurnal rhythm in adrenal insufficiency. |
| Stress / adrenal crisis | 100–200 mg/day | IV | High-dose cover for illness, surgery or adrenal crisis. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Physiologic cortisol replacementLife-sustaining replacement in adrenal insufficiency, mimicking the natural rhythm. | restores normal cortisol | Clinical | |
| Mild anti-inflammatory actionEffective for mild inflammation topically and at higher systemic doses. | low potency | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Fluid retention / hypertensionSodium and water retention raising blood pressure, more than with synthetic glucocorticoids. | Moderate | Common at higher doses | Clinical | |
| HPA suppression / over-replacementDoses above physiologic needs suppress residual adrenal function and cause Cushingoid features. | Moderate | With supraphysiologic dosing | Clinical | |
| Catabolism (supraphysiologic)At doses well above replacement, muscle and bone catabolism appear as with any glucocorticoid. | Moderate | Only at anti-inflammatory doses | Clinical |