ZK-283197

The primary goal of the planned study is to investigate the efficacy and safety of ZK 283197 in the dosage of 2 and 3 mg ingested once daily during a period of 8 weeks for the treatment of hot flushes. In order to be able to assess the efficacy of the test substance, this is compared with the efficacy of 1 mg Estradiol and placebo. The comparator Estradiol is a certified hormone preparation, which is already used for the treatment of hot flushes as standard treatment. After passing the screening, volunteers will start with a run-in phase followed by a 8 weeks treatment and a follow-up phase. 112 postmenopausal women with hot flushes and without relevant prior diseases will participate in three European countries (2 study sites in Germany, 1 study site in Great Britain and 1 study site in The Netherlands) in this study.