[Alternatives to hormone replacement therapy: raloxifene and tibolone]

The bone is an active metabolic organ influenced by many substances like calcium, vitamin D, bisphosphonates etc. The postmenopausal osteoporosis is mainly caused by estrogen deficiency and hormone replacement therapy (HRT) has been shown to prevent the progress of osteoporosis. The following paper describes two alternatives to the classical HRT: raloxifen and tibolon. Raloxifen belongs to the selective estrogen receptor modulators (SERM) showing an estrogen-agonistic effect on bone. There is evidence that bone mineral density (BMD) is growing with treatment. In a three year study (MORE), a statistically significant decrease of lumbar spine fractures was demonstrated (RR 0.5-0.7). Furthermore there was a statistically significant reduction of receptor positive breast cancer (RR 0.10). Raloxifen shows beneficial effects on the lipids and does not induce endometrial proliferation. In the field of climacteric complaints, it is an estrogen-antagonist and therefore inappropriate for this indication. Tibolon--a steroid hormone--and their three metabolites have estrogenic, gestagenic and weak androgenic effects on the different target organs. As expected, there is an increase of bone mineral density comparable to that of HRT or raloxifen; data of fracture rates with long-term therapy are missing. The substance and their metabolites are equivalent to HRT in the treatment of climacteric complaints. Tibolon shows some beneficial effects on the lipids and a lower bleeding rate compared to HRT. Raloxifen and tibolon are interesting alternatives to HRT which allow a more individual treatment of patients in the postmenopause.