Glucocorticoid Equivalent Dose Memory Trick
The easy trick to remember glucocorticoid equivalent doses is: 0.75/4/5/20 for dexamethasone/methylprednisolone/prednisolone/hydrocortisone, though the most authoritative 2024 guidelines actually specify slightly different ranges: 0.25-0.5/3-5/4-6/15-25 mg respectively for physiologic replacement doses 1.
The Standard Memory Aid
The classic mnemonic uses these approximate equivalent doses:
- Dexamethasone: 0.75 mg
- Methylprednisolone: 4 mg
- Prednisolone: 5 mg
- Hydrocortisone: 20 mg
This translates to a potency ratio of roughly 1:5:5:25 when comparing dexamethasone to the others 2.
What the Most Recent Guidelines Actually Say
However, the 2024 European Society of Endocrinology/Endocrine Society joint guidelines provide more nuanced ranges for physiologic daily dose equivalents 1:
- Hydrocortisone: 15-25 mg
- Prednisolone: 4-6 mg
- Methylprednisolone: 3-5 mg
- Dexamethasone: 0.25-0.5 mg
These ranges reflect individual variability in bioavailability and metabolism, as endogenous cortisol production is only about 9-10 mg/day, but oral replacement requires higher doses due to incomplete absorption 1.
Alternative Simplified Version
The UK perioperative guidelines from 2020 provide another easy conversion: 10 mg hydrocortisone ≈ 2 mg prednisolone ≈ 0.1 mg dexamethasone 2. This gives you a 1:5:100 ratio that's simple to remember.
Important Clinical Caveats
The equivalency tables are primarily validated for anti-inflammatory and genomic effects, NOT for all glucocorticoid actions. Research shows that different steroids have dramatically different potencies for non-genomic effects 3. For example:
- Methylprednisolone and dexamethasone cause significantly more hyperglycemia than prednisolone or hydrocortisone at "equivalent" doses 4
- Dexamethasone lacks mineralocorticoid activity entirely, making it inadequate for primary adrenal insufficiency 2
- Methylprednisolone penetrates lung tissue better than other steroids, potentially explaining superior efficacy in respiratory conditions 5
Practical Application
When converting between steroids in clinical practice:
- For adrenal insufficiency replacement: Use the guideline ranges (15-25 mg hydrocortisone or 4-6 mg prednisolone daily) 1
- For anti-inflammatory dosing: The 0.75/4/5/20 trick works reasonably well 6
- For stress dosing: Remember that 8 mg dexamethasone = 200 mg hydrocortisone and covers 24 hours 2
The bottom line: Your original "0.25/4/5/20" is close but slightly off—the more accurate version is 0.5/4/5/20 for quick calculations, though individual patient dosing should use the ranges specified in the 2024 guidelines 1.