Methylprednisolone to Prednisolone Dose Equivalency
1 mg of methylprednisolone is equivalent to 1.25 mg of prednisolone. This means that to convert methylprednisolone to prednisolone, you multiply the methylprednisolone dose by 1.25 (or conversely, prednisolone is 80% as potent as methylprednisolone). 1, 2
Conversion Rationale
The FDA drug label explicitly states that "4 mg of methylprednisolone is equivalent to 5 mg of prednisolone," which establishes the 1:1.25 ratio (4 × 1.25 = 5). 2
Multiple clinical practice guidelines confirm this equivalency, with methylprednisolone 48 mg being approximately equivalent to 60 mg of prednisone or prednisolone (48 × 1.25 = 60). 1
This conversion factor is consistently applied across various clinical contexts, including polymyalgia rheumatica management where dosing recommendations reference "prednisone equivalent" doses that can be calculated from methylprednisolone using this ratio. 3
Clinical Application
When switching from methylprednisolone to prednisolone, multiply the methylprednisolone dose by 1.25 to maintain equivalent anti-inflammatory potency. 4
For example, if a patient is receiving methylprednisolone 16 mg daily, the equivalent prednisolone dose would be 20 mg daily (16 × 1.25 = 20). 1
This conversion is critical when tapering corticosteroids or switching formulations, as maintaining equivalent anti-inflammatory potency prevents disease flares while minimizing the risk of adrenal insufficiency from abrupt dose changes. 4
Important Caveats
Methylprednisolone has less mineralocorticoid effect than hydrocortisone at equivalent anti-inflammatory doses, which may be clinically relevant when considering electrolyte effects, though this distinction is less important when comparing methylprednisolone to prednisolone (both have minimal mineralocorticoid activity). 4
The conversion applies to both oral and intravenous formulations when calculating total daily doses, though bioavailability differences between routes should be considered in specific clinical scenarios. 5