Ra. Lobo et al., A novel intermittent regimen of norgestimate to preserve the beneficial effects of 17 beta-estradiol on lipid and lipoprotein profiles, AM J OBST G, 182(1), 2000, pp. 41-49
OBJECTIVE: This study was undertaken to evaluate the effects of 3 dosage le
vels of intermittent norgestimate plus a constant dose of 17 beta-estradiol
on blood lipid and lipoprotein concentrations in 236 postmenopausal women.
STUDY DESIGN: In this multicenter, double-blind, parallel-group trial the s
ubjects were randomly assigned to receive 1 mg estradiol daily or 1 mg estr
adiol daily plus intermittent (3 days off and 3 days on) doses of 30 mu g,
90 mu g, or 180 mu g norgestimate for 360 days.
RESULTS: The regimens of 1 mg estradiol plus 30 mu g norgestimate and 1 mg
estradiol plus 90 mu g norgestimate increased concentrations of high-densit
y lipoprotein cholesterol, HDL2 high-density lipoprotein cholesterol, HDL3
high-density lipoprotein cholesterol (except the regimen of 1 mg estradiol
plus 30 mu g norgestimate at 7 months), and apolipoprotein apo A-I. They de
creased total cholesterol concentration, low-density lipoprotein cholestero
l concentration, low-density lipoprotein/high-density lipoprotein ratio, ap
olipoprotein apo B concentration, and Lp(a) lipoprotein concentration, and
they attenuated estradiol-induced increases in triglyceride concentrations.
In contrast, the regimen of 1 mg estradiol plus 180 mu g norgestimate redu
ced concentrations of high-density lipoprotein cholesterol, high-density li
poprotein HDL3 cholesterol, and apolipoprotein apo A-I at 7 months and incr
eased the low-density lipoprotein/high-density lipoprotein ratio at 7 month
s.
CONCLUSIONS: An intermittent regimen of norgestimate at 30 or 90 mu g daily
administered for 3 days off followed by 3 days on preserved the beneficial
lipid and lipoprotein changes induced by continuous therapy with 1 mg 17 b
eta-estradiol daily; however, 180 mu g norgestimate did not do so.