From the Guidelines
To convert dexamethasone to prednisone, use a ratio of 1:6, as 1 mg of dexamethasone is equivalent to approximately 6 mg of prednisone, based on the fact that dexamethasone is 25 times more powerful than hydrocortisone and prednisone is 4 times more powerful than hydrocortisone 1. When making this conversion, it's essential to consider the duration of action as well; dexamethasone has a longer half-life compared to prednisone, so dosing frequency may need adjustment. Some key points to consider when converting between these corticosteroids include:
- Dexamethasone has minimal mineralocorticoid effects compared to prednisone, which may be relevant for patients sensitive to fluid retention or blood pressure effects.
- The equivalent dose of prednisone 60 mg is 10 mg for dexamethasone, as stated in the guidelines for corticosteroid therapy for idiopathic sudden sensorineural hearing loss 1.
- Always taper corticosteroids when switching between them if the patient has been on therapy for more than 1-2 weeks to prevent adrenal insufficiency.
- Monitor patients after conversion for signs of under or over-replacement, including changes in their underlying condition, blood glucose levels, blood pressure, and fluid status. For practical purposes, this conversion ratio can be used to determine the equivalent dose of prednisone for a patient taking dexamethasone, and vice versa, to ensure the patient receives an equivalent anti-inflammatory effect.
From the Research
Conversion Ratio
- The conversion ratio from dexamethasone to prednisone is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
Dexamethasone and Prednisone Comparison
- Studies have compared the efficacy of dexamethasone and prednisone in various conditions, such as acute asthma 4, 5 and croup 6.
- These studies suggest that dexamethasone and prednisone have similar efficacy in certain conditions, but the optimal dosage and duration of treatment may vary 4, 5, 6.
Dosage and Duration
- A study on acute asthma found that 2 days of dexamethasone (16 mg/day) was at least as effective as 5 days of prednisone (50 mg/day) in returning patients to their normal level of activity and preventing relapse 4.
- Another study on acute pediatric asthma found that 2 doses of dexamethasone (0.6 mg/kg, maximum 16 mg) provided similar efficacy with improved compliance and fewer side effects than 5 doses of prednisone (2 mg/kg, maximum 60 mg) 5.
Biotransformation
- A study on the biotransformation of prednisone and dexamethasone by cytochrome P450 based systems found that the conversion products of these steroids could serve as novel potential drug candidates 3.