Adrenal steroids as parameters of the bioavailability of MA and MPA
| Autor: | Dirk Sleijfer, Henk Van Veelen, Pax H.B. Willemse, Lambert D. Dikkeschei, T. Tjabbes |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Medroxyprogesterone
medicine.medical_specialty Hydrocortisone Dose Estrone medicine.drug_class Biological Availability Dehydroepiandrosterone Breast Neoplasms Medroxyprogesterone Acetate chemistry.chemical_compound Adrenal Cortex Hormones Internal medicine Antineoplastic Combined Chemotherapy Protocols medicine Humans Medroxyprogesterone acetate Estradiol business.industry Megestrol Acetate Androstenedione Megestrol Bioavailability Endocrinology Oncology chemistry Estrogen Megestrol acetate Female business medicine.drug |
| Zdroj: | European Journal of Cancer and Clinical Oncology. 26:359-362 |
| ISSN: | 0277-5379 |
| DOI: | 10.1016/0277-5379(90)90234-k |
| Popis: | Serum levels of cortisol (C), androstenedione (A), dehydroepiandrosterone (D), estrone (E 1 ) and estradiol (E 2 ) were chosen as parameters to compare the bioavailability of megestrol acetate (MA) and medroxyprogesterone acetate (MPA) in postmenopausal patients with advanced breast cancer. In 36 patients randomized to MPA, the levels of A ( 13% vs. 19% ) and C ( 6% vs. 8% ) were slightly lower than in 36 patients on MA, but D-levels ( 68% vs. 59% ) and E 1 or E 2 , were similar. The correlation between baseline C and A disappeared during treatment. Treatment levels of E 1 and E 2 were correlated. There was no correlation between individual drug levels and any steroid, indicating a maximal suppression. After ingestion of a single dose of MA or MPA, peak levels were found after 2–3 h for MA and 3–4 h for MPA. Four hours after ingestion, the levels of A and C were similar, 40–60% of baseline values, while D levels remained unaltered. Doubling the dose of either drug did not enhance hormone suppression, indicating that the drug dosage is maximally suppressive. In conclusion, although the median serum MA levels are double those of MPA, suppression of A, C and D is usually similar, with corresponding estrogen levels, demonstrating a comparable and maximal bioavailability. Higher dosages of MA or MPA will not increase their pharmacological effects any further. |
| Databáze: | OpenAIRE |
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