Intranasal estradiol: new formulation. Intranasal oestrogen delivery system: just a gimmick

(1) Many oral and transdermal (patch and gel) estradiol preparations are already available for controlling menopausal symptoms due to oestrogen deficiency. (2) Marketing authorization has now been granted in Europe for an intranasal delivery system, which produces a high, brief plasma estradiol peak. (3) According to two clinical trials, the symptomatic effects of 300 micrograms of estradiol daily by the intranasal route is similar to that of 50 micrograms /day transdermally (unblinded trial) and 2 mg/day orally (double-blind trial). (4) The most frequent side effects are intranasal reactions (in approximately 50% of patients), breast pain (30-40% of patients), and metrorrhagia (approximately 7% of cycles). (5) The long-term consequences of such high plasma estradiol peaks, including the risk of breast cancer, are unknown. (6) Intranasal estradiol is not reimbursed in France, unlike other oestrogen preparations for use in menopausal women. (7) In practice, oral and transdermal delivery systems, with which we have lengthy experience, are adequate for relieving menopausal symptoms. The intranasal route offers no proven advantage, and its long-term risks are unknown.