Equivalent Oral Prednisolone (Omnacortil) Dose When Shifting from Injectable Methylprednisolone
When converting from injectable methylprednisolone (MPS) to oral prednisolone (Omnacortil), use a conversion ratio of approximately 1:1.25, meaning 120 mg of injectable methylprednisolone is equivalent to 150 mg of oral prednisolone. 1
Conversion Guidelines
- According to the American College of Rheumatology, oral prednisolone dosing should maintain equivalent anti-inflammatory and immunosuppressive effects when transitioning from intramuscular methylprednisolone 1
- The FDA drug label indicates that methylprednisolone 4 mg is equivalent to prednisolone 5 mg, establishing a 1:1.25 conversion ratio for oral administration 2
- For maintenance therapy in rheumatologic conditions, oral prednisolone is typically started at 12.5-25 mg/day when converting from injectable therapy 1
Dosing Considerations
- Single daily dosing of oral prednisolone is generally preferred over divided doses for better compliance and effectiveness 1
- Patient-specific factors such as disease severity, comorbidities (diabetes, hypertension, osteoporosis, glaucoma), and previous response to glucocorticoid therapy should influence the exact conversion dose 1
- The bioavailability of oral prednisolone is complete (bioavailability fraction of 1.063), meaning the drug is fully absorbed when taken orally 3
Disease-Specific Dosing
- For multiple sclerosis exacerbations, 1250 mg oral methylprednisolone provides similar bioavailability to 1000 mg IV methylprednisolone, suggesting a similar conversion ratio for high-dose pulse therapy 4
- For maintenance therapy in rheumatoid arthritis, weekly intramuscular methylprednisolone doses range from 40-120 mg, which would convert to approximately 50-150 mg of oral prednisolone 2
- In dermatologic conditions, methylprednisolone doses of 40-120 mg IM would convert to 50-150 mg oral prednisolone 2
Monitoring After Conversion
- Assess clinical response within 2-4 weeks of conversion to ensure adequate disease control 1
- Monitor for steroid-related adverse effects, which may differ between administration routes 1
- Be aware that methylprednisolone shows linear pharmacokinetics, while prednisolone demonstrates dose-dependent pharmacokinetics with higher clearance at higher doses 5
Common Pitfalls and Caveats
- Avoid assuming that injectable and oral doses are equivalent without applying the proper conversion ratio 1, 2
- Remember that the relative properties of corticosteroids may be greatly altered when injected intramuscularly compared to oral administration 2
- For high-dose pulse therapy (such as in MS relapses), evidence suggests that lower doses (625 mg/day for 3 days) may not be inferior to standard high doses (1250 mg/day for 3 days) in terms of clinical and radiological response 6