Working Diagnosis.

Steroid Equivalence Calculator

❍ Glucocorticoid potency conversion · prednisolone-equivalent dosing
Consultation support tool. Equivalences are approximate and apply to oral administration only unless otherwise stated. Potency ratios vary between sources; this tool uses NZF/BNF and standard pharmacology references. They do not account for individual pharmacokinetics, route, formulation, or clinical context. Mineralocorticoid and HPA-suppressive effects differ from glucocorticoid potency. Always apply clinical judgement.
❍ Step 1: Enter current steroid dose
❍ Prednisolone equivalent

Dose Conversion Result

Input dose
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Prednisolone equivalent
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mg prednisolone / day
Sub-physiologic Replacement Low-medium High Very high
❍ Equivalent doses for other glucocorticoids

Equianalgesic Steroid Doses

These doses produce equivalent anti-inflammatory (glucocorticoid) effect. Mineralocorticoid activity, duration, and side-effect profile differ - see cards below. Fludrocortisone is excluded (primarily mineralocorticoid).

❍ Adrenal axis and receptor profile

Steroid Properties - Your Input Drug

❍ Reference

Glucocorticoid Equivalence Table

Oral administration. Doses producing equivalent anti-inflammatory effect to prednisolone 5 mg. Source: NZF (based on BNF).1

Drug Equiv. dose (oral) Potency vs pred. Mineral. activity Duration NZ notes
Hydrocortisone 20 mg 0.25�- ++ moderate Short (8-12 h) Identical to cortisol. Used in adrenal insufficiency; IV stress dosing. Funded.
Cortisone acetate 25 mg 0.2�- ++ moderate Short (8-12 h) Prodrug → hydrocortisone. Used in primary adrenal insufficiency (with fludrocortisone). Funded.
Prednisolone 5 mg (reference) 1.0�- (ref) + low Intermediate (12-36 h) Standard first-line oral steroid in NZ. Available 1 mg, 5 mg, 25 mg. Funded.
Prednisone 5 mg 1.0�- + low Intermediate (12-36 h) Prodrug → prednisolone. Avoid in severe hepatic failure. Interchangeable with prednisolone in most patients.
Methylprednisolone 4 mg 1.25�- trace Intermediate (12-36 h) Oral (Medrone) and IV/IM (Solu-Medrol, Depo-Medrol). Useful in oedema-sensitive situations. Funded IV.
Triamcinolone 4 mg 1.25�- nil Intermediate (12-36 h) IM depot (Kenacort-A 10/40 mg/mL) for intra-articular / IM injection. No mineralocorticoid activity. Restricted funded.
Deflazacort 6 mg 0.83�- trace Intermediate (12-36 h) Used in Duchenne muscular dystrophy. Possibly less osteoporosis and weight gain per equivalent dose.2 Limited NZ availability (Special Authority).
Dexamethasone 0.75 mg 6.7�- nil Long (36-54 h) No mineralocorticoid effect. Used in cerebral oedema, croup, anti-emesis, COVID-19 (RECOVERY: 6 mg/day �- 10 days).3 Funded.
Betamethasone 0.75 mg 6.7�- nil Long (36-54 h) IM antenatal corticosteroids for fetal lung maturation (11.4 mg betamethasone phosphate/acetate IM �- 2 doses, 24 h apart). Funded.
Fludrocortisone - 10�- (GC)
but see note
++++ very high Intermediate Not used for glucocorticoid effect. Mineralocorticoid replacement: 50-200 mcg/day. Primary adrenal insufficiency, congenital adrenal hyperplasia, orthostatic hypotension. Funded.
❍ Clinical considerations

HPA Axis Suppression & Clinical Thresholds

HPA suppression risk: Prednisolone ≥5 mg/day (or equivalent) for more than 3 weeks causes significant HPA suppression. Never stop abruptly after prolonged courses - taper and monitor for adrenal insufficiency.
Dose Context

Physiologic cortisol production: ~10-20 mg hydrocortisone/day ≈ 2.5-5 mg prednisolone/day. Doses at or below this level approach physiologic replacement.

Low dose (<7.5 mg prednisolone/day): Risk of HPA suppression if used for >3 weeks. Cushingoid side effects less likely with long-term use at this range, but not absent.

Medium dose (7.5-20 mg prednisolone/day): Significant Cushingoid side effects (weight gain, glucose intolerance, mood changes, skin fragility) with prolonged use. Common starting range for moderate inflammatory conditions.

High dose (20-40 mg prednisolone/day): Standard for acute asthma, COPD exacerbation, autoimmune flares. Taper after short courses (5-10 days); if prolonged, wean slowly.

Very high / pulse dose (>40-60 mg prednisolone/day, or IV methylprednisolone 500-1000 mg): Specialist use for MS relapse, lupus nephritis, vasculitis, pemphigus. Requires specialist oversight.

Sick Day Rules (NZ MoH / Endocrine Society guidance)

Who needs sick day rules? Any patient on prednisolone ≥5 mg/day (or equivalent) for >3 weeks, or known adrenal insufficiency.

Minor illness (fever, mild infection): Double the usual dose for the duration of the illness. Do not miss doses. Resume normal dose when recovered.

Vomiting / unable to take oral medication: Administer hydrocortisone IM (100 mg IM stat) and seek emergency care immediately. Patients should have an emergency injection kit if on chronic steroids.

Perioperative steroid cover:

  • Minor procedures (local anaesthetic, minor dental): Take usual dose; no supplementation needed.
  • Moderate surgery (general anaesthetic): Hydrocortisone 25 mg IV at induction + 25 mg IV 8-hourly for 24 h, then usual dose.
  • Major surgery / critical illness: Hydrocortisone 50 mg IV 8-hourly or 200 mg/24 h infusion. Continue until able to return to oral, then rapid taper.

Note: Patients with adrenal insufficiency should carry a MedicAlert and steroid emergency card at all times.

General Principles of Tapering

Short courses (<3 weeks, any dose): Can usually stop abruptly unless high dose. No taper required.

Longer courses or uncertainty: Taper by 10-20% every 1-2 weeks. Slow the taper as you approach physiologic doses (≤5-7.5 mg prednisolone/day).

Near physiologic doses: Reduce by 1 mg prednisolone every 2-4 weeks. Some patients require 6-12+ months to wean off completely (especially polymyalgia rheumatica, adrenal insufficiency recovery).

Monitoring during taper: Symptoms of adrenal insufficiency include fatigue, nausea, joint pain, hypotension, and dizziness - especially on dose reduction days. Consider morning cortisol testing when at ≤5 mg/day prednisolone equivalent.

Steroid-sparing agents: For diseases requiring long-term steroids, consider early introduction of DMARDs (methotrexate, azathioprine, hydroxychloroquine) to allow dose reduction. Discuss with specialist.

Side Effects to Anticipate

Osteoporosis (most preventable serious risk): For ≥7.5 mg prednisolone/day expected for ≥3 months: start calcium + vitamin D supplementation (calcium 1000-1500 mg/day, vitamin D 800-1000 IU/day) and consider bisphosphonate (alendronate first-line in NZ if eligible). DXA at baseline if prolonged course anticipated.4

Diabetes / hyperglycaemia: Screen fasting glucose at baseline; monitor especially with doses >10 mg/day. Post-lunch glucose rise most prominent - check at 4-6 h post-dose. Adjust hypoglycaemic therapy accordingly.

Cardiovascular: Hypertension, dyslipidaemia, and fluid retention occur with medium-to-high doses. Monitor BP and lipids; favour steroids with low mineralocorticoid activity (dexamethasone, methylprednisolone) where mineralocorticoid effects are undesirable.

Infection risk: Immunosuppression significant at >15-20 mg prednisolone/day. Consider PCP prophylaxis (trimethoprim/sulfamethoxazole 80/400 mg 3�- weekly) if anticipated prolonged high-dose course.

Gastric protection: Steroid alone does not significantly increase peptic ulcer risk, but combined with NSAIDs markedly increases risk. Add PPI if concurrent NSAID use or high GI risk.5

Eye complications: Long-term use causes posterior subcapsular cataract and can worsen glaucoma. Annual eye review for patients on chronic corticosteroids.

Mood and cognition: Mood swings, insomnia, mania, and frank psychosis can occur at high doses. Inform patient; taper early if psychological effects occur. Avoid in patients with untreated psychiatric illness.

Skin and adrenal suppression: Skin thinning, bruising, and striae with prolonged use. HPA suppression as detailed above.

Common Indications by Steroid Choice

Prednisolone: Default oral steroid for most inflammatory conditions in NZ GP practice. Well-funded, available in 1 mg/5 mg/25 mg tablets.

Hydrocortisone: Adrenal insufficiency replacement (oral, ~15-20 mg/day in divided doses mimicking diurnal rhythm) and IV stress dosing (25-50 mg 6-8 hourly). Also used for short-term acute allergic reactions IV.

Dexamethasone: Preferred where no mineralocorticoid effect is desired or duration must be long (cerebral oedema, croup, COVID-19 hospitalised patients, post-operative nausea). Note: 6 mg dexamethasone/day �- 10 days for hospitalised COVID-19 (RECOVERY trial data).3

Methylprednisolone IV: Pulse therapy for MS relapse (1 g/day �- 3-5 days), SLE nephritis, vasculitis. Requires secondary/tertiary care involvement.

Betamethasone IM: Antenatal corticosteroids for threatened preterm labour <34-36 weeks. Two doses 11.4 mg IM 24 h apart.

Triamcinolone IM/intra-articular: Intra-articular injection for large joint inflammation (knee, shoulder). IM depot for patients unable to take oral or requiring sustained systemic effect. Maximum 3 intra-articular injections per joint per year (cartilage protection).

Fludrocortisone: Mineralocorticoid replacement in primary adrenal insufficiency (Addison's disease), salt-wasting congenital adrenal hyperplasia, and sometimes orthostatic hypotension. Not a glucocorticoid substitute.

❍ Sources

References

  1. New Zealand Formulary (NZF). Corticosteroids - equivalent anti-inflammatory doses. Wellington: NZF; 2024. Available from: https://nzf.org.nz [cited 2025].
  2. Griggs RC, Moxley RT, Mendell JR, et al. Prednisone in Duchenne dystrophy: a randomized, controlled trial defining the time course and dose response. Clinical Investigation in Duchenne Dystrophy Group. Arch Neurol. 1991;48(4):383-8.
  3. RECOVERY Collaborative Group. Dexamethasone in hospitalized patients with Covid-19. N Engl J Med. 2021;384(8):693-704.
  4. Compston J. Glucocorticoid-induced osteoporosis: an update. Curr Rheumatol Rep. 2020;22(1):7.
  5. Lanas A, Perez-Aisa MA, Feu F, et al. A nationwide study of mortality associated with hospital admission due to severe gastrointestinal events and those associated with nonsteroidal antiinflammatory drug use. Am J Gastroenterol. 2005;100(8):1685-93.
  6. Nieman LK. Pharmacologic use of glucocorticoids. UpToDate [Internet]. Wolters Kluwer; 2024 [cited 2025].
  7. Rang HP, Ritter JM, Flower RJ, Henderson G. Rang & Dale's Pharmacology. 9th ed. Edinburgh: Elsevier; 2019. Chapter 33: Anti-inflammatory and immunosuppressant drugs.
  8. Best Practice Advisory Centre New Zealand (BPAC NZ). Corticosteroids in primary care. Dunedin: BPAC NZ; 2023. Available from: https://bpac.org.nz [cited 2025].