1. Clinical Overview
Hydrocortisone is a synthetic glucocorticoid, identical to the endogenous hormone cortisol produced by the adrenal cortex. It is a short-acting corticosteroid with both glucocorticoid and mineralocorticoid activity, making it a cornerstone for adrenal insufficiency replacement therapy and a potent anti-inflammatory and immunosuppressive agent. In the 10mg oral tablet form, it is primarily used for physiological replacement in conditions like Addison's disease and secondary adrenal insufficiency.
| Onset | Duration | Bioavailability |
|---|---|---|
| Oral: 1-2 hours for physiological effects; anti-inflammatory effects may take several hours to days. | Biological half-life: 8-12 hours. Duration of action for anti-inflammatory effects is 8-12 hours, necessitating multiple daily doses for replacement therapy. | Approximately 96% following oral administration. |
2. Mechanism of Action
Hydrocortisone binds to intracellular glucocorticoid receptors (GR) and mineralocorticoid receptors (MR). The drug-receptor complex translocates to the nucleus, where it modulates gene transcription. It induces the synthesis of anti-inflammatory proteins (e.g., lipocortin-1) and inhibits the synthesis of pro-inflammatory mediators (e.g., cytokines, prostaglandins, leukotrienes). It also has profound effects on carbohydrate, protein, and fat metabolism, and influences electrolyte and water balance via mineralocorticoid activity.
3. Indications & Uses
- Primary Adrenal Insufficiency (Addison's Disease)
- Secondary/Tertiary Adrenal Insufficiency
- Congenital Adrenal Hyperplasia (as part of replacement regimen)
- Adrenal Crisis (requires IV/IM administration, not oral 10mg tablet)
4. Dosage & Administration
Adult Dosage: Adrenal Insufficiency (Replacement): 20-30 mg daily in 2-3 divided doses (e.g., 10-15 mg on waking, 5-10 mg in afternoon). Pharmacological: 20-240 mg daily in divided doses, tailored to condition.
Administration: Take with or immediately after food to minimize GI upset. For replacement therapy, follow a circadian rhythm schedule: larger dose in the morning (6-8 AM), smaller dose in the early afternoon (2-4 PM). Do not stop abruptly if used for more than 2-3 weeks; taper gradually. For stress coverage (fever, injury, surgery), patients on replacement must double or triple their dose as per physician's 'sick day rules'.
5. Side Effects
Common side effects may include:
- Insomnia, mood changes, nervousness
- Increased appetite, weight gain
- Fluid retention, edema
- Dyspepsia, heartburn
- Skin thinning, easy bruising
- Hirsutism
- Menstrual irregularities
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Phenytoin, Phenobarbital, Rifampicin | Increased hepatic metabolism of hydrocortisone, reducing its efficacy. Dose increase may be needed. | Major |
| Ketoconazole, Itraconazole, Clarithromycin | Inhibit CYP3A4, decreasing hydrocortisone metabolism, leading to increased effects/toxicity. Dose reduction may be needed. | Major |
| Warfarin | Effect may be altered (increased or decreased INR). Close monitoring required. | Moderate |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | Increased risk of GI ulceration and bleeding. | Major |
| Diuretics (e.g., Furosemide, Hydrochlorothiazide) | Enhanced potassium loss, leading to severe hypokalemia. | Major |
| Antidiabetic drugs (Insulin, Metformin) | Hydrocortisone causes hyperglycemia, antagonizing their effect. Increased antidiabetic dose may be needed. | Major |
| Vaccines (Live: BCG, MMR, Varicella) | Diminished antibody response and increased risk of vaccine-induced infection. Contraindicated. | Major |
7. Patient Counselling
- DO take the medicine exactly as prescribed, especially the timing for replacement therapy.
- DO carry a steroid emergency card or wear medical alert jewelry stating you are on steroid therapy.
- DO inform all doctors, dentists, and surgeons about your hydrocortisone use before any treatment.
- DO double your dose during fever, infection, injury, or before major dental/surgical procedures as instructed (for replacement therapy).
- DON'T stop taking the medicine suddenly if you have been on it for more than 2-3 weeks.
- DON'T take over-the-counter NSAIDs (like ibuprofen) without consulting your doctor.
- DON'T ignore signs of infection like fever, sore throat, or cough.
8. Toxicology & Storage
Overdose: Acute overdose can cause cushingoid symptoms: moon face, central obesity, hypertension, hyperglycemia, hypokalemia, fluid retention, psychosis. Chronic overdose leads to iatrogenic Cushing's syndrome, adrenal suppression, osteoporosis, and increased infection risk.
Storage: Store below 30°C. Protect from light and moisture. Keep the tablet strip/blister in the outer carton. Keep out of reach of children. Do not use after the expiry date printed on the pack.