Methylprednisolone to Prednisone Conversion
Solu-Medrol (methylprednisolone) 4 mg IV is equivalent to prednisone 5 mg orally. 1, 2
Standard Conversion Ratio
- The established conversion is 4:5 (methylprednisolone:prednisone), meaning methylprednisolone 4 mg equals prednisone 5 mg. 1, 2
- This conversion applies whether methylprednisolone is given intravenously or orally, as the potency ratio remains constant. 2
- The FDA drug label explicitly states this equivalency for clinical dosing purposes. 2
Clinical Application in Perioperative Settings
- For patients on chronic oral prednisone who become nil-by-mouth perioperatively, convert to IV hydrocortisone or methylprednisolone using the 5:4 ratio (prednisone 5 mg = methylprednisolone 4 mg = hydrocortisone 20 mg). 1
- British Society of Gastroenterology guidelines specifically recommend this conversion for IBD patients undergoing surgery who have been on oral corticosteroids for more than 4 weeks. 1
- Do not increase steroid dosing for "stress coverage" in the perioperative period—simply maintain the equivalent dose, as randomized trials in IBD surgery have shown no benefit to stress-dose steroids. 1
Bioavailability Considerations
- Oral prednisone and IV methylprednisolone have comparable bioavailability when given in equivalent doses. 3, 4
- A randomized trial in hospitalized asthmatic children found no difference in length of stay between oral prednisone 2 mg/kg/dose twice daily versus IV methylprednisolone 1 mg/kg/dose four times daily (equivalent total daily doses). 3
- In MS patients, 1250 mg oral prednisone produced similar area-under-the-curve measurements to 1000 mg IV methylprednisolone, confirming comparable absorption. 4
Important Caveats
- The conversion assumes normal GI absorption—in patients with severe GI disease, malabsorption, or inability to take oral medications, IV administration may be necessary regardless of theoretical equivalency. 1
- For high-dose pulse therapy (e.g., 500-1000 mg methylprednisolone), the IV route is preferred for reliability and immediate effect, particularly in organ-threatening disease. 1
- Methylprednisolone is 5 times more potent than hydrocortisone and 1.25 times more potent than prednisone on a milligram-per-milligram basis. 5, 2