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Simple methods for estimation of prednisone intake and metabolism
R Maayan1, R Segal, E J Feuerman
1Endocrinological Laboratory, Beilinson Medical Center, Petah Tiqva, Israel.
Biomedicine & Pharmacotherapy = Biomedecine & Pharmacotherapie
|January 1, 1988
Summary
Monitoring prednisone (a corticosteroid) intake is crucial for patients on high doses. Simple urine tests can accurately assess prednisone and prednisolone levels, ensuring effective treatment and bioavailability.
Area of Science:
- Endocrinology
- Clinical Chemistry
- Pharmacology
Background:
- High-dose prednisone (over 40 mg/day) requires careful laboratory monitoring, especially when clinical response is inconsistent with dosage.
- Prednisone and prednisolone share structural similarities with endogenous corticosteroids (cortisone and cortisol), enabling the development of related assays.
Purpose of the Study:
- To evaluate simple, cost-effective methods for assessing prednisone and prednisolone intake and bioavailability.
- To establish reliable laboratory markers for monitoring high-dose corticosteroid therapy.
Main Methods:
- Radioimmunoassay (RIA) for cortisol was adapted to measure free urinary prednisolone.
- Quantification of free and metabolized prednisone and prednisolone was performed using 17-hydroxycorticosteroids (17-OHCS) in 24-hour urine collections.
Main Results:
- Free urinary prednisolone levels showed a strong linear correlation with the administered prednisone dose (r = 0.9310), representing 6.5-11% of the daily dose.
- Total, conjugated, and free 17-OHCS in urine also correlated linearly with the prednisone dose, with the strongest correlation observed for total 17-OHCS (r = 0.9060).
- Approximately 40% of the administered prednisone was excreted as total 17-OHCS.
Conclusions:
- Radioimmunoassay for cortisol is a valid method for estimating free urinary prednisolone.
- Urinary 17-OHCS provide a reliable measure of prednisone metabolism and excretion.
- These simple laboratory methods can effectively monitor prednisone intake and bioavailability in patients receiving high-dose therapy.