Tibolone is a synthetic steroid that has progestogenic and some androgenic properties as well as oestrogenic effects. As it has effects of all three groups of hormones produced by the ovaries (the female gonads) it has been called gonadomimetic.
Tibolone is a compound that can be selectively metabolized by individual tissues to its estrogenic, progestogenic, or androgenic metabolites and hence exhibits tissue-specific hormonal effects. Tibolone also lowers sex hormone binding globulin, thus increasing free estradiol and testosterone levels. Tibolone alleviates climacteric vasomotor symptoms and displays a dominant progestogenic effect on the endometrium. It normalizes the vaginal karyopyknotic and maturation indexes and alleviates symptomatic atrophic vaginitis. Women treated with tibolone report significant reductions in vaginal dryness and dyspareunia, effects that may be secondary to both estrogenic and androgenic actions. Randomized studies indicate tibolone has positive effects on mood compared with placebo and alleviates several adverse mood parameters to a similar extent as conventional hormone replacement therapy. Improved mood is associated with increased plasma beta-endorphin. With respect to cognition, tibolone seems to improve semantic memory but does not significantly improve recognition memory. Tibolone is associated with improvements in sexual function that seem to be greater than those achieved with standard hormone replacement therapy.
Tibolone is indicated for the following conditions: Treatment of the climacteric symptoms resulting from the natural or artificial menopause. Prevention of postmenopausal and post oophorectomy osteoporosis and improvement of bone-mineral density in patients with established post-menopausal osteoporosis. Vaginal atrophy. Prevention of frequent UTI and urinary incontinence in postmenopausal women.
Published studies indicate beneficial effects of tibolone on both libido and mood, which otherwise significantly compromise physical, psychological, and social well-being. Hence, tibolone provides another option for menopausal women experiencing loss of libido as part of their symptomatology or who have persistent low libido despite adequate estrogen/progestin replacement therapy. Tibolone does not increase or decrease the risk of cardiovascular disease. Also there has been no evidence of an increased risk of thromboembolism with tibolone.