Ospemifene

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.