Progestogens long-term effects

Tibolone is an agonist at estrogen and progestogen receptors, with weak androgenic activity. It is given as an alternative to hormone replacement therapy, without added progestogen, and has been in use for some 30 years to treat bone loss in post-menopausal women. Some long-term studies (for example over 10 years) appear to have confirmed its safety and relative freedom from adverse effects (1). In particular there is little or no increase in thrombotic events and the incidence of breast tenderness is low. 

Tibolone (Livial) is widely used in treatment of vasomotor symptoms and prevention of osteoporosis. The parent compound itself is devoid of activity, but it is metabolized in a tissue-selective manner to three metabolites that have predominantly estrogenic, progestogenic, and androgenic activities. The drug appears to increase bone mineral density and decrease vasomotor symptoms without stimulating the endometrium, but its effects on fractures, breast cancer, and long-term outcomes remain to be established. 

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