Hydrocortisone (Oral Replacement)

How it works

Hydrocortisone is synthetic cortisol that binds glucocorticoid receptors to replace deficient endogenous cortisol, restoring metabolic, cardiovascular, and stress-response function, typically dosed to mimic the circadian rhythm.

Prescribing in practice

• The most important safety point is the risk of life-threatening adrenal crisis if doses are missed or not increased during illness; patients require sick-day dosing rules, an emergency injection kit, and a steroid emergency card.
• Replacement must not be stopped abruptly, and doses are increased to provide stress cover for intercurrent illness, surgery, or trauma.
• Concurrent enzyme-inducing drugs can increase cortisol clearance and may necessitate dose adjustment.

Monitoring

Monitor clinically for adequacy of replacement and for signs of over- or under-treatment, including blood pressure, weight, and well-being rather than routine cortisol levels.

Counselling the patient

• Never stop your steroid suddenly, and always carry your steroid emergency card.
• Double your dose during fever or illness and know how to use your emergency injection if vomiting prevents tablets.
• Seek urgent medical care if you cannot keep tablets down or feel severely unwell.

Evidence & guidelines

Glucocorticoid replacement with hydrocortisone is standard in adrenal insufficiency, and the MHRA and NHS have issued steroid emergency card guidance to reduce adrenal crisis.