title: The effects of menopause and hormone replacement therapies on prednisolone and erythromycin pharmacokinetics.
abstract: The pharmacokinetics of oral and intravenous prednisolone and intravenous erythromycin were examined in premenopausal women, postmenopausal women not undergoing hormone replacement therapy, postmenopausal women undergoing estrogen replacement therapy, and postmenopausal women undergoing estrogen and progestin replacement therapy. The unbound clearance of prednisolone was significantly lower in postmenopausal women (11.6 +/- 2.3 ml/min/kg) than in premenopausal women (16.6 +/- 3.5 ml/min/kg). A comparable difference was also observed in total clearance and in half-life. The bioavailability and volume of distribution of prednisolone were unaffected by menopausal status. Hormone replacement therapies did not significantly affect prednisolone pharmacokinetics. In contrast to prednisolone elimination, erythromycin elimination, as measured by the erythromycin breath test, was not significantly affected by either menopausal status or hormone replacement therapy. In addition, there was no correlation between prednisolone clearance and the erythromycin breath test result. Although cytochrome P450 3A4 (CYP3A4) has been implicated in steroid hormone metabolism, these results suggest that another enzyme system, which is decreased in menopause (rather than simply an age effect), is also involved in prednisolone metabolism.
authors.affiliation: Department of Pharmacy, University of California, San Francisco 94143-0446, USA.
authors.forename: R Z
authors.initials: RZ
authors.lastname: Harris
authors.forename: S M
authors.initials: SM
authors.lastname: Tsunoda
authors.forename: P
authors.initials: P
authors.lastname: Mroczkowski
authors.forename: H
authors.initials: H
authors.lastname: Wong
authors.forename: L Z
authors.initials: LZ
authors.lastname: Benet
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D000893:Anti-Inflammatory Agents / Q000493:pharmacokinetics*; D001682:Biological Availability; D001944:Breath Tests; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004917:Erythromycin / Q000493:pharmacokinetics*; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006207:Half-Life; D006801:Humans; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism; D011239:Prednisolone / Q000493:pharmacokinetics*; D011372:Progestins / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000893:Anti-Inflammatory Agents; D004967:Estrogens; D011372:Progestins; D004917:Erythromycin; D003577:Cytochrome P-450 Enzyme System; D011239:Prednisolone; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human