Products
Ospemifene is commercially available in tablet form (Osphena). It was approved in the United States in February 2013. It is not yet registered in many countries.
Structure and properties
Ospemifene (C24H23ClO2, Mr = 378.9 g/mol) exists as a white crystalline powder that is insoluble in water. It is a triphenylethylene derivative and has a nonsteroidal structure. Ospemifene is a metabolite of toremifene and has a similar structure to tamoxifen and toremifene.
Effects
Ospemifene is an agonist and antagonist at the estrogen receptor. At the endometrium, it has estrogen agonistic effects.
Indications
For the treatment of pain during intercourse (dyspareunia) due to menopause associated with vaginal atrophy.
Dosage
According to the SmPC. Tablets are taken once daily with a meal.
Contraindications
For complete precautions, see the drug label.
Interactions
Ospemifene is metabolized by CYP3A4, CYP2C9, and CYP2C19 and has high protein binding. Corresponding drug-drug interactions are possible. Ospemifene should not be combined with other SERMs.
Adverse effects
The most common possible adverse effects include flushing, vaginal discharge, muscle cramps, and increased sweating. As with other estrogenic agents, serious side effects such as endometrial cancer, venous thrombosis, and stroke are rarely possible.