Hydrocortisone
An IV or IM steroid. 100 mg for asthma, adrenal crisis and acute severe colitis; 100 mg 6-hourly in colitis.
On this page
Uses
- Acute asthma when oral steroids can't be taken.
- Adrenal crisis.
- Acute severe ulcerative colitis.
- Adjunct in refractory anaphylaxis (not first-line).
Adult dose
| Indication | Dose |
|---|---|
| Acute asthma | 100 mg IV every 6 hours |
| Adrenal crisis | 100 mg IV or IM immediately, then 50 mg every 6 hours (or 200 mg/24 hours infusion) |
| Acute severe colitis | 100 mg IV every 6 hours |
Children's dose
4 mg/kg IV (max 100 mg) every 6 hours; adrenal crisis 2 mg/kg (max 100 mg) immediately.
How it works
Hydrocortisone is the drug form of cortisol, the body's own glucocorticoid. It enters cells and binds glucocorticoid receptors, switching off genes for inflammatory cytokines and switching on anti-inflammatory proteins. This reduces airway and bowel inflammation over hours, not minutes. It also has significant mineralocorticoid (salt-retaining) activity, which is why it is the right drug in adrenal crisis, where both cortisol and aldosterone effects are missing. Anti-inflammatory benefit takes 4 to 6 hours to appear.
When it is used
- Adrenal crisis: this is where hydrocortisone is life-saving. Suspect it in anyone on long-term steroids, or with known Addison's disease or hypopituitarism, who becomes unwell with vomiting, low BP, low sodium, high potassium or low glucose.
- Acute asthma and COPD exacerbation when the patient cannot swallow prednisolone. If they can swallow, oral prednisolone works just as well.
- Acute severe ulcerative colitis while assessing for rescue therapy.
- Anaphylaxis: no longer routine in initial treatment; consider only for refractory reactions or persistent asthma-like symptoms, after adrenaline.
- Perioperative steroid cover for patients on long-term steroids.
It is not a substitute for adrenaline in anaphylaxis, and dexamethasone is preferred where a long-acting steroid with no salt retention is wanted (for example, cerebral oedema, croup, bacterial meningitis).
Cautions
- Raises blood sugar; monitor.
- Patients on long-term steroids need extra cover when ill (sick-day rules).
Contraindications
There are no absolute contraindications in an emergency. In suspected adrenal crisis, never delay hydrocortisone for tests: take a cortisol sample if convenient, then give the dose. Be cautious in uncontrolled systemic infection without antimicrobial cover.
Side effects (short courses)
- High blood glucose, especially in diabetics.
- Fluid retention, high BP, low potassium.
- Agitation, insomnia, mood change, steroid psychosis (rare).
- Masks signs of infection and perforation (important in colitis).
Side effects (long-term use)
Adrenal suppression, osteoporosis, diabetes, weight gain, skin thinning, cataract, peptic ulcer (especially with NSAIDs), muscle weakness and infection risk.
Interactions
- NSAIDs and aspirin: higher GI bleeding risk; consider a PPI.
- Rifampicin, phenytoin and carbamazepine speed up breakdown; patients on these may need higher replacement doses.
- Loop diuretics, salbutamol and theophylline add to low potassium.
- Raises glucose, so insulin or oral hypoglycaemic needs may increase.
Monitoring
- Capillary glucose at least 4 times a day while on IV doses.
- Electrolytes (sodium, potassium) daily; BP and fluid balance.
- In adrenal crisis: BP, glucose, sodium and potassium hourly at first, with generous IV 0.9% sodium chloride.
- In colitis: stool chart, CRP, abdominal examination and abdominal X-ray as per your unit's colitis protocol.
Pregnancy and breastfeeding
Hydrocortisone is largely inactivated by the placenta and is the steroid of choice for replacement in pregnancy. Do not withhold it in adrenal crisis or acute asthma. It is compatible with breastfeeding.
Practical tips
- It comes as a 100 mg vial of powder (sodium succinate). Reconstitute with 2 mL water for injection and give slowly IV over at least 1 to 2 minutes, or IM.
- Give the first dose of steroid in asthma early, in the first hour; it does nothing for bronchospasm in the first few hours, so do not wait for it to work.
- Sick-day rules for patients on regular steroids: double the usual oral dose during fever or illness, and use the emergency IM injection or seek urgent care if vomiting.
- Write "steroid-dependent" clearly on the chart for patients on long-term steroids so doses are not missed when nil by mouth.
- Hydrocortisone cream and the IV injection are completely different products; check the route.
A patient on long-term steroids who is vomiting and hypotensive has adrenal crisis until proven otherwise. Give 100 mg hydrocortisone now.
See Acute asthma, Inflammatory bowel disease flares, Anaphylaxis and The shocked patient. For exam background, read Adrenal hormones and Endocrine drugs.
Frequently asked questions
What is the hydrocortisone dose in adrenal crisis?
100 mg IV or IM immediately, then 50 mg every 6 hours, with IV fluids.
Is hydrocortisone better than prednisolone in asthma?
No. If the patient can swallow, oral prednisolone 40 to 50 mg is as effective. Use IV hydrocortisone when oral intake is not possible.
Should hydrocortisone be given in anaphylaxis?
Not routinely. Current guidance reserves steroids for refractory anaphylaxis or ongoing asthma symptoms, after adrenaline. They do not act quickly enough to treat the emergency.
Can hydrocortisone be given IM?
Yes. IM hydrocortisone is used when there is no IV access, especially in adrenal crisis.
Used in these guides
Sources
Doses on this page are typical doses from the sources above. Always confirm with a current drug reference, the product leaflet and your hospital protocol, especially in children, pregnancy and kidney or liver disease.
For FCPS Part 1
Revising for FCPS Part 1? Hydrocortisone is covered in our textbook chapter Endocrine drugs, with practice MCQs.