Tibolone, sold under the brand name Livial among others, is a medication which is used in menopausal hormone therapy and in the treatment of postmenopausal osteoporosis and endometriosis. The medication is available alone and is not formulated or used in + some more technical info Tibolone is a synthetic 19-nor steroid that functions as a tissue selective prodrug; after oral administration it is rapidly metabolized in the liver and target tissues to three principal active metabolites, 3alpha-hydroxytibolone, 3beta-hydroxytibolone and the Delta4-isomer, which together confer estrogenic activity on bone and vaginal tissue, progestogenic activity in the endometrium, and androgenic activity in certain peripheral tissues. The compound is typically supplied as 1.25 mg or 2.5 mg oral film-coated tablets for daily dosing in menopausal symptom control and prevention of bone loss, undergoes extensive first-pass metabolism by hepatic enzymes, shows high plasma protein binding, and is monitored clinically for standard hormone therapy safety parameters including lipid profile, endometrial status and thromboembolic risk.
Parent: Tibolone
Active pharmaceutical ingredient batches and finished tablets are characterized by an assay and related-substance specification; typical assay acceptance is about 98.0 to 102.0 percent of the labeled amount, total known and unknown impurities are commonly limited to not more than 1.0 percent by area on validated HPLC, and individual unspecified impurities are typically limited to 0.2 percent or lower. Principal related substances encountered include Delta4-tibolone (an isomeric progestogenic metabolite) often limited to 0.3 to 0.5 percent, and the 3alpha- and 3beta-hydroxytibolone metabolites which when present as degradation or synthetic byproducts are controlled to about 0.1 to 0.2 percent each; residual solvents and heavy metals are controlled to ICH and pharmacopeial limits. Identity and purity are routinely confirmed using high performance liquid chromatography with UV detection, impurity profiling by LC-MS, and stress degradation studies to identify hydrolytic or oxidative degradants.
Tibolone has not been universally banned but regulatory actions and market withdrawals have occurred in some jurisdictions following safety signals from postmarketing surveillance and randomized trials, notably an increased risk of stroke in older women and signals relating to breast cancer and venous thromboembolism; authorities responded by updating contraindications, restricting indications or withdrawing approval locally where risk-benefit was judged unfavorable for specific populations.
Disadvantages include increased risk of thromboembolic events and possibly stroke in older women, potential stimulation of breast tissue with uncertain long-term cancer risk, androgenic adverse effects such as acne, hirsutism and changes in lipid profile in some patients, contraindications in active hepatic disease and hormone-sensitive cancers, and the need for clinical monitoring similar to other systemic hormone therapies.
Hormone replacement therapy usually refers to administration of separate estrogens alone or combined estrogen-progestogen regimens, while tibolone is a single synthetic steroid prodrug that is metabolized to active moieties with mixed estrogenic, progestogenic and androgenic activities; tibolone tends to produce tissue-selective effects, often causes less cyclical uterine bleeding, and has a distinct pharmacokinetic and receptor interaction profile compared with conventional estrogen plus progestogen combinations.
Tibolone itself has low direct receptor affinity but is converted enzymatically to three main metabolites: 3alpha- and 3beta-hydroxytibolone which exhibit estrogen receptor agonism in bone and vaginal tissue, and the Delta4-isomer which binds progesterone and androgen receptors producing progestogenic effects in the endometrium and androgenic activity in peripheral tissues; the net clinical effect is tissue-selective modulation of estrogenic, progestogenic and androgenic pathways determined by local metabolism and receptor distribution.
