Prednisone to Methylprednisolone Conversion
Use a 1.25:1 conversion ratio when converting between prednisone and methylprednisolone (5 mg prednisone = 4 mg methylprednisolone), based on their relative glucocorticoid potencies. 1
Standard Conversion Formula
- Prednisone 5 mg = Methylprednisolone 4 mg 1
- Prednisone 60 mg = Methylprednisolone 48 mg 1
- Methylprednisolone is approximately 1.25 times more potent than prednisone (or prednisone is 0.8 times as potent as methylprednisolone) 1
Clinical Application Examples
Multiple clinical guidelines consistently reference this conversion ratio in practice:
- For immune checkpoint inhibitor toxicities: When guidelines recommend "prednisone 1 mg/kg/day (or equivalent dose of methylprednisolone)," this refers to the 1.25:1 ratio 2
- For polymyalgia rheumatica: Initial doses of 12.5-25 mg prednisone equivalent daily can be converted using this standard ratio 2
- For lupus nephritis: Pulse methylprednisolone 500-2500 mg followed by oral prednisone uses this conversion framework 2
Practical Conversion Table
| Prednisone Dose | Methylprednisolone Dose |
|---|---|
| 5 mg | 4 mg |
| 10 mg | 8 mg |
| 20 mg | 16 mg |
| 40 mg | 32 mg |
| 60 mg | 48 mg |
| 80 mg | 64 mg |
Important Clinical Considerations
Pharmacokinetic differences exist despite equivalent anti-inflammatory potency:
- Methylprednisolone demonstrates linear, predictable pharmacokinetics with no dose or time dependency 3
- Prednisone shows dose-dependent pharmacokinetics due to saturable protein binding, making target concentrations more difficult to predict 3
- Methylprednisolone may be preferred when precise dosing is critical due to its more predictable concentration-dose relationship 3
Route-specific considerations:
- Oral and intravenous formulations are bioequivalent when using the 1.25:1 conversion ratio 4
- In hospitalized children with asthma, oral prednisone 2 mg/kg twice daily was equivalent to IV methylprednisolone 1 mg/kg four times daily (same total daily dose using the conversion ratio) 4
- IV methylprednisolone costs approximately 10 times more than oral prednisone without superior efficacy for most indications 4
Timing of administration:
- Both drugs should be administered in the morning (before 9 AM) to minimize HPA axis suppression 5, 6
- Single daily dosing is preferred over divided doses when possible 5, 6
Common Pitfalls to Avoid
- Do not confuse methylprednisolone with methylprednisone - these are different compounds 2
- Do not use a 1:1 conversion - this will result in underdosing when switching from prednisone to methylprednisolone 1
- Account for formulation differences: The FDA labels specify dose ranges of 4-48 mg/day for methylprednisolone versus 5-60 mg/day for prednisone, reflecting the potency difference 5, 6
- Consider non-genomic effects: At very high doses (pulse therapy), the relative potencies may differ from standard conversions, with methylprednisolone potentially having advantages over prednisolone in pulse therapy scenarios 7