Low-dose estradiol spray: a novel treatment for vasomotor instability in postmenopausal women

This article describes a novel transdermal estradiol spray developed for the treatment of menopausal vasomotor instability. The spray delivers estradiol directly into the subcutaneous microcirculation achieving the advantages of estradiol patches, creams and gels but with minimal skin reaction, patient inconvenience or cosmetic shortcomings associated with transdermal methods. In the one published Phase III clinical trial, postmenopausal women (n = 454) with eight or more moderate-to-severe hot flashes per day applied each morning, one, two or three estradiol 90 microl sprays (each containing estradiol 1.53 mg) versus matching placebo sprays. There was a significant decrease in hot flash frequency and intensity at weeks 4 and 12 compared with corresponding placebo groups (p < 0.010). The systemic estradiol delivery rates at week 12 were approximately 0.021, 0.029 and 0.040 mg/day for the 1-, 2- and 3-spray doses, respectively. There were common adverse events similar to those previously reported with transdermal estradiol, except for skin irritation, which was very low. The spray is a well-tolerated, cosmetically attractive and convenient method of delivering low-dose, transdermal estradiol.