Initial 17beta-estradiol dose for treating vasomotor symptoms.

OBJECTIVE: To compare the efficacy of different doses of 17beta-estradiol (E2) for relief of vasomotor symptoms in menopausal women.

METHODS: This was a randomized, double-masked, placebo-controlled, 12-week study in which 333 menopausal women with moderate or severe hot flushes were assigned to treatment with 0.25 mg, 0.5 mg, 1 mg, or 2 mg oral micronized 17beta-E2, or placebo. The number and severity of hot flushes were recorded daily.

RESULTS: There was a significant linear correlation between increased dosage of 17beta-E2 and decreased moderate to severe hot flushes per week (P <.001). Rapid reduction in moderate to severe hot flushes was only achieved with 1 and 2 mg, showing a significant difference from placebo at week 4 (P <.05). At week 4, half the women on placebo had reduced moderate to severe hot flushes of at least 52%; the corresponding figures were 56%, 69%, 86%, and 91% for 0.25, 0.5, 1, and 2 mg, respectively. At week 12, all doses except 0.25 mg were significantly better than placebo for reducing moderate to severe hot flushes (P <.001). Although there were no significant differences, twice as many women in the 2-mg group discontinued treatment due to adverse events, compared with the placebo group.

CONCLUSION: Oral micronized 17beta-E2 showed a dose-response effect for reducing moderate and severe hot flushes in menopausal women. 17beta-E2 1 mg appeared to be the most useful initial dose.