Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Glucocorticoid replacement and steroid sick-day rules
Endocrinology and metabolism · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Time-critical presentation
A patient with adrenal insufficiency who cannot retain oral medication, becomes hypotensive, confused or severely weak, or has persistent vomiting or diarrhoea should use emergency hydrocortisone as trained and call 999 for hospital treatment. Oral sick-day dosing is not adequate when absorption is unreliable.
Purpose and principles
Deliver physiological glucocorticoid replacement, teach proportionate stress dosing and create reliable oral, injectable and peri-procedural safeguards that prevent crisis without chronic overexposure.
Replacement is a balance. Too little glucocorticoid causes fatigue, nausea, weight loss, postural symptoms and crisis vulnerability. Too much promotes weight gain, hypertension, diabetes, infection, osteoporosis, skin thinning and sleep disturbance. Because no routine biomarker precisely reports tissue replacement, symptom pattern, dose timing and cardiometabolic review are central.
Sick-day rules temporarily reproduce the cortisol response that a healthy adrenal would mount. Oral escalation is for a patient who is awake, haemodynamically stable and absorbing tablets. Injection and emergency transfer are for vomiting, severe diarrhoea, major injury, marked deterioration or crisis features. This route distinction is more important than memorising every minor-illness example.
Patients at risk include established primary or secondary insufficiency and many people with exogenous HPA suppression. Safety infrastructure must follow the patient through primary care, emergency departments, dentistry, endoscopy and surgery. The Steroid Emergency Card communicates risk, but it cannot substitute for an accessible medicine supply and practical injection rehearsal.
Key points
Indications, selection and cautions
Under-replacement
Early-morning collapse, fatigue before the next dose, anorexia, nausea, weight loss or postural dizziness can indicate inadequate amount, timing, absorption or adherence. Exclude anaemia, infection and underlying disease activity.
Over-replacement
Progressive weight gain, bruising, proximal weakness, hypertension, hyperglycaemia, insomnia and recurrent infection suggest excessive total exposure or poorly timed late dosing.
Oral stress suitable
Fever, systemic infection, antibiotic-treated illness or moderate physiological stress in a stable person who can eat, drink and retain medication generally activates the written oral sick-day plan.
Injection thresholdRed flag
Repeated vomiting, severe diarrhoea, inability to swallow, major trauma, collapse, confusion or shock makes oral absorption unsafe and requires emergency hydrocortisone plus urgent hospital assessment.
Procedure exposureRed flag
Fasting, bowel preparation, sedation, general or regional anaesthesia and tissue trauma change cortisol need. A missing peri-procedure plan is a safety defect even when the regular morning tablet was taken.
Assessment before treatment
01Structured dose and timing reviewFirst step
Why
Determine actual daily glucocorticoid exposure and whether symptoms cluster around dose gaps.
Interpretation and limitations
Include formulation, clock times, shift work, missed doses, recent sick dosing and all additional steroid routes. A diary can reveal late-day excess or early-morning deficiency more clearly than random cortisol.
02Weight, postural blood pressure and metabolic profile
Why
Monitor clinical adequacy and chronic harms of replacement.
Interpretation and limitations
Weight loss and postural fall favour deficiency; weight gain, hypertension and rising HbA1c suggest excess, but comorbidity and fludrocortisone also contribute. Use serial change rather than one measurement.
Primary adrenal insufficiency may cause sodium and potassium abnormalities, while stress dosing commonly raises glucose. Significant derangement or inability to hydrate lowers the threshold for hospital care.
04Morning cortisol during supervised taper
Why
Assess HPA recovery in selected glucocorticoid-induced suppression once exposure is near physiological range.
Interpretation and limitations
Treatment approach
01Daily replacementMinimise peaks and gapsFirst stepStable primary, secondary or tertiary adrenal insufficiency outside acute physiological stress.+
1Agree a total daily hydrocortisone or prednisolone regimen with endocrinology, giving the largest hydrocortisone component on waking and adapting clock time for shift workers.
2Review symptoms before and after doses, adherence, interacting medicines and metabolic/bone effects; change one variable at a time and document the maintenance schedule clearly.
3Ensure mineralocorticoid replacement is separately optimised in primary disease and that every routine prescription includes enough reserve for sick-day dosing.
02Intercurrent illnessOral stress dose or injectFever, systemic infection, vomiting, diarrhoea, trauma or rapid clinical deterioration.+
1If stable and absorbing, follow the written NICE-consistent oral plan: at least 40 mg hydrocortisone daily in divided doses or at least 10 mg prednisolone daily during significant stress.
Regimens, contraindications and interactions
Short-acting physiological glucocorticoid replacement that permits circadian-style dosing and flexible stress escalation.
Hydrocortisone maintenance
Usually 15 to 25 mg orally per day in two to four divided doses for adults under NICE guidance, tailored to the individual.
Late doses can disturb sleep and chronic excess causes metabolic and bone harm. Do not reduce below a safe plan during illness and do not stop suddenly.
Temporarily increases glucocorticoid availability when a stable patient can swallow and absorb treatment.
Hydrocortisone oral sick-day regimen
At least 40 mg orally daily in two to four divided doses during significant physiological stress, continued until the acute illness resolves.
This is not sufficient with recurrent vomiting, severe diarrhoea, collapse or confusion. Monitor glucose and hydration, and seek clinical review when illness is prolonged or worsening.
Provides stress coverage for people whose maintenance replacement uses prednisolone or where the written endocrine plan selects it.
Prednisolone sick-day alternative
At least 10 mg orally daily in one or two divided doses during significant stress, adjusted to the existing regimen and specialist plan.
People already taking 10 mg or more daily may not need a higher total, but timing may need division. Prolonged exposure increases infection, glucose, mood and bone risks.
Complications, monitoring and follow-up
At routine review, chart weight, blood pressure including posture, glucose or HbA1c risk, sleep, infection, bruising and bone-health factors alongside dose timing.
During stress dosing, monitor hydration, urine output and glucose, and seek assessment for prolonged fever, dyspnoea, worsening pain, confusion or inability to maintain intake.
Inspect the emergency kit at least at scheduled reviews and after every use; record expiry, replacement prescription and injection demonstration by patient or carer.
For procedures, reconcile the anaesthetic chart, ward prescription and discharge step-down so high-dose cover is neither omitted nor continued indefinitely.
During exogenous-steroid taper, monitor recurrence of the treated disease separately from glucocorticoid withdrawal and true adrenal insufficiency; these may require different actions.
Special situations
Clock time follows waking
A night worker's physiological morning is not necessarily 08:00. Replacement timing should follow the sleep-wake cycle while preserving the principle of larger exposure early in the active period.
Vomiting changes route
Sick-day success depends on absorption. Repeating oral tablets through recurrent vomiting creates false reassurance; the trained injection and emergency-transfer pathway is the safeguard.
Card plus kit plus skill
A card alerts clinicians, a kit supplies medicine and rehearsal creates usable competence. Removing any one component weakens the prevention system substantially.
Taper has two governors
At high therapeutic doses, inflammatory-disease control dictates reduction. Near physiological range, HPA recovery becomes the limiting concern and may justify a slower schedule or testing.
Hyperglycaemia is managed, not feared
JBDS guidance supports glucose surveillance and treatment during glucocorticoid exposure. The possibility of high glucose must not prompt omission of necessary stress replacement.
Common pitfalls
01
Giving one universal sick-day instruction without distinguishing stable oral absorption from vomiting or collapse.
02
Increasing maintenance steroid indefinitely after a brief illness and creating chronic over-replacement.
03
Telling a patient to stop replacement on the morning of a fasting procedure without parenteral cover.
04
Issuing a Steroid Emergency Card but no injection kit, spare tablets or practical demonstration.
05
Testing morning cortisol without accounting for the formulation and required pre-test steroid withholding.
06
Attributing every symptom during taper to adrenal failure and overlooking relapse of the original inflammatory disease.
Practice
Two practice questions
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Question 1 of 2
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Endocrinology and metabolismOriginal SBA
Vomited replacement dose
A patient with adrenal insufficiency vomits within twenty minutes of taking hydrocortisone during a febrile illness. What advice best matches NICE sick-day guidance?
Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Physiological replacement aims to mimic the cortisol day: the largest hydrocortisone dose is generally taken on waking, with smaller later doses and avoidance of unnecessary late-evening exposure.
NICE adult replacement options include hydrocortisone 15 to 25 mg daily in divided doses or prednisolone 3 to 5 mg daily when appropriate; individual clinical response and specialist review govern selection.
For significant physiological stress, NICE advises at least 40 mg oral hydrocortisone daily in two to four divided doses or at least 10 mg prednisolone daily in one or two divided doses until the acute illness resolves.
A patient already taking prednisolone 10 mg or more daily may not need a higher total sick-day dose, but dose timing and the individual endocrine plan still matter.
If vomiting occurs within 30 minutes of an oral dose, NICE advises repeating after vomiting settles at double the original dose; further vomiting triggers intramuscular hydrocortisone and emergency attendance.
Fever, infection requiring antibiotics, significant trauma and invasive procedures need stress planning. Minor emotional stress or a brief uncomplicated cold does not justify indefinite supraphysiological dosing.
Every at-risk patient needs an NHS Steroid Emergency Card, extra oral tablets and training for a 100 mg IM emergency injection, with a carer trained where possible.
Never stop long-term glucocorticoid abruptly. Tapering is determined by the inflammatory indication first, then by hypothalamic-pituitary-adrenal recovery assessment once near physiological exposure.
Stress dosing can worsen glucose, fluid retention, blood pressure, infection and mental state, but these risks are managed with monitoring; they do not justify under-treating major physiological stress.
Peri-operative cover depends on procedure, anaesthesia, fasting and baseline steroid exposure. Use the current local anaesthetic-endocrine protocol and confirm who will prescribe, administer and step down each dose.
Only test under a protocol that specifies which steroid to withhold and for how long. Long-acting or cross-reacting steroids can make an apparently reassuring value misleading.
05Emergency kit and competence check
Why
Test whether the prevention system will function under pressure.
Interpretation and limitations
Confirm in-date hydrocortisone, needles, syringe, written instructions, card and ability to demonstrate reconstitution/injection. Replace missing items immediately rather than documenting education alone.
06Procedure-specific risk assessment
Why
Match cover to invasiveness, fasting, anaesthesia and baseline adrenal reserve.
Interpretation and limitations
Use the current local peri-operative guideline and communicate the induction dose, postoperative regimen and oral step-down across surgical, anaesthetic and ward charts.
2If an oral dose is vomited within 30 minutes, wait for vomiting to settle and repeat at double the original dose. Further vomiting, severe diarrhoea or deterioration crosses to the injection branch.
3Give 100 mg IM hydrocortisone as trained, call 999 and continue emergency assessment when absorption fails or crisis features appear; do not remain at home to see whether the injection is enough.
03Procedure or taperPlan transitions explicitlyUpcoming surgery, endoscopy, dental intervention, bowel preparation or reduction of chronic therapeutic steroids.+
1For a procedure, notify the team in advance, use the local cover schedule and specify fasting-day steroid route, intra-operative cover, postoperative doses and oral resumption.
2For chronic steroid reduction, taper according to control of the treated disease until physiological range, then slow or test HPA recovery under endocrine or prescribing-specialist guidance.
3Keep emergency precautions active until recovery is demonstrated and the specialist plan states they can stop; communicate the endpoint to the patient, GP and pharmacy.
Bridges life-threatening loss of absorption or evolving crisis until IV therapy and monitored resuscitation are available.
Hydrocortisone emergency injection
100 mg intramuscularly immediately when oral medication cannot be retained or severe deterioration occurs, followed by 999 transfer and hospital treatment.
Training, in-date equipment and carer familiarity are essential. Do not delay injection while seeking telephone advice and do not treat it as a reason to avoid emergency attendance.