The pharmacokinetics and selected pharmacodynamic responses to methylprednisolone were investigated in six men and six premenopausal women after a dose of 0.6 mg/kg ideal body weight. Women (luteal phase) exhibited a greater methylprednisolone clearance (0.45 versus 0.29 L/hr/kg) and shorter elimination half-life (1.7 versus 2.6 hours) than men. The volume of distribution of methylprednisolone was similar when normalized for ideal body weight. Pharmacodynamic models were used to examine the methylprednisolone suppressive effects on cortisol secretion and basophil and helper T lymphocyte trafficking. A significantly smaller 50% inhibitory concentration (IC 50 ) value (0.1 versus 1.7 ng/ml) was seen in the women for suppression of cortisol secretion, indicating increased sensitivity. However, the area under the concentration-time curve of effect was similar for both groups. The IC 50 values for effects of methylprednisolone on basophil trafficking related to estradiol concentrations in a log-linear fashion in women, with increased sensitivity found at higher estradiol concentrations. Men displayed a greater 24-hour net suppression in blood basophil numbers, but no difference was observed in net cortisol and helper T lymphocyte suppression between the sexes. These findings suggest that methylprednisolone dosages should be based on ideal body weight. Although women are more sensitive to methylprednisolone as measured by cortisol suppression, they eliminate the drug more quickly, generally producing a similar net response.Male subjects typically have been used in most drug studies. However, the findings of these studies are applied clinically to both male and female patients, despite their physiologic differences. Of the studies that have enrolled both men and women, most fail to analyze their findings by gender and instead treat all the subjects as one homogeneous group. 1 This bias in clinical research has been of concern within the health professions. [2][3][4] The literature currently lacks guidelines regarding dosing regimens based on gender.Copyright © 1993 by Mosby-Year Book, Inc.Reprint requests: William J. Jusko, PhD, Hochstetter 565, School of Pharmacy, State University or New York at Buffalo, Buffalo, NY 14260. Presented at the Ninety-fourth Annual Meeting of the American Society for Clinical Pharmacology and Therapeutics, March 24-26, 1993, Honolulu, Hawaii (Abstract: Clin Pharmacol Ther 1993;53:183). NIH Public Access Author ManuscriptClin Pharmacol Ther. Author manuscript; available in PMC 2014 October 23. Published in final edited form as:Clin Pharmacol Ther. 1993 October ; 54(4): 402-414. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptGender-related differences in disposition have been observed for numerous drugs. The total and unbound clearance of diazepam, which undergoes oxidative metabolism, was found to be greater in women. 5 Clearance of oxazepam (total and unbound) 6 and acetaminophen, 7 both of which undergo glucuronide conjugation, is significantly greater ...

The authors studied the pharmacokinetics of levodopa (LD) with and without pramipexole (PPX) in men and postmenopausal women with PD. Patients on stable dose of carbidopa/LD were randomized to receive escalating doses of placebo or PPX over 7 weeks. LD and PPX pharmacokinetics were performed after a single test dose 25/100 of carbidopa/LD, before initiation of PPX or placebo, at 1.5 mg/d and 4.5 mg/d of PPX or placebo. Compared to men, women had greater LD bioavailability. PPX did not alter LD bioavailability, and PPX pharmacokinetics were equivalent in men and women.

OC steroids appear to inhibit methylprednisolone metabolism. However, mixed changes in several responses occur, indicating that women can probably receive similar doses of methylprednisolone irrespective of OC steroid use.