Less effect of intranasal than oral hormone therapy on factors associated with venous thrombosis risk in healthy postmenopausal women.
Author(s): Hemelaar M, Rosing J, Kenemans P, Thomassen MC, Braat DD, van der Mooren MJ
Affiliation(s): Project Aging Women and Institute for Cardiovascular Research-Vrije Universiteit (ICaR-VU), Department of Obstetrics and Gynecology, VU University Medical Center, De Boelelaan 1117, 1081 HV, PO Box 7057, 1007 MB Amsterdam, The Netherlands.
Publication date & source: 2006-07, Arterioscler Thromb Vasc Biol., 26(7):1660-6. Epub 2006 Apr 27.
Publication type: Multicenter Study; Randomized Controlled Trial
OBJECTIVE: To compare the effects of intranasal and oral administration of 17beta-estradiol (E2) and norethisterone(acetate) [NET(A)] in healthy postmenopausal women on activated protein C (APC) resistance and other hemostatic parameters associated with venous thrombosis. METHODS AND RESULTS: In this 2-center, randomized, double-blind, 1-year trial, 90 postmenopausal women (56.6+/-4.7 years of age) received daily either an intranasal spray with 175 microg/275 microg E2/NET (n=47) or 1 mg/0.5 mg oral E2/NETA (n = 43). Normalized APC sensitivity ratios (nAPCsr) were determined with a thrombin generation-based APC resistance test. After 1 year, the increase in nAPCsr was smaller in the intranasal than in the oral group: 11% (95% CI, 1% to 22%) versus 53% (95% CI, 37% to 72%). Overall, the decrease in antithrombin and increase in prothrombin fragment 1+2 (F1+2) were smaller and the decrease in free protein S larger in the intranasal compared with the oral group after 1 year. In both groups, the decreases in protein C and prothrombin, and the increase in d-dimer were similar. CONCLUSIONS: Compared with oral E2/NETA therapy, intranasal administration of E2/NET had less effect on APC resistance and on a number of other parameters associated with venous thrombosis. This observation suggests the possibility of a lower venous thrombosis risk for intranasal E2/NET compared with oral therapy.
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