Hydrocortisone to Solu-Medrol (Methylprednisolone) Conversion
20 mg hydrocortisone is equivalent to 4 mg methylprednisolone (Solu-Medrol). 1
Standard Conversion Ratio
Methylprednisolone is 5 times more potent than hydrocortisone, meaning you divide the hydrocortisone dose by 5 to obtain the equivalent methylprednisolone dose. 1
The established anti-inflammatory equivalence is: hydrocortisone 20 mg = methylprednisolone 4 mg = prednisone/prednisolone 5 mg = dexamethasone 0.75 mg. 1
This conversion ratio applies to both oral and intravenous administration routes. 1
Clinical Application Examples
For perioperative stress coverage, hydrocortisone 20 mg IV is equivalent to methylprednisolone 4 mg IV and prednisolone 5 mg oral. 1, 2
When converting from hydrocortisone 100 mg IV every 6 hours (400 mg/day total) to methylprednisolone, the equivalent dose is methylprednisolone 60-80 mg daily. 1
For septic shock management, hydrocortisone 300 mg/day is equivalent to methylprednisolone 60 mg/day. 1
Important Mineralocorticoid Considerations
Methylprednisolone has minimal mineralocorticoid activity at therapeutic doses, whereas hydrocortisone possesses substantial mineralocorticoid effects causing sodium retention and potassium loss. 1
When converting from hydrocortisone to methylprednisolone in patients with primary adrenal insufficiency, monitor potassium levels closely as supplementation needs may decrease due to loss of mineralocorticoid effect. 1
Methylprednisolone is unsuitable as sole replacement therapy for primary adrenal insufficiency because it lacks the mineralocorticoid activity needed for sodium and volume homeostasis—fludrocortisone must be added separately. 1
Pharmacokinetic Differences
Hydrocortisone has a plasma elimination half-life of approximately 90 minutes, requiring multiple daily doses to maintain physiologic coverage. 1
Methylprednisolone has a longer duration of action than hydrocortisone, allowing for less frequent dosing in most clinical scenarios. 1
Both oral formulations have excellent bioavailability and rapid absorption. 1
Common Clinical Pitfalls
Do not confuse methylprednisolone with methylprednisone—they are different compounds with different potencies. 1
The 5:1 conversion ratio (hydrocortisone:methylprednisolone) may require adjustment in obese individuals or those taking CYP3A4-inducing medications (phenytoin, rifampin, carbamazepine), though high-quality evidence for specific modifications is limited. 1
When using methylprednisolone for stress-dose coverage in patients with known adrenal insufficiency, remember that it does not replace fludrocortisone in primary adrenal insufficiency—mineralocorticoid replacement must continue separately. 1