Introduction
Ospemifene is a new selective non-hormonal estrogen receptor modulator (SERM) that is used for the treatment of moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy, due to menopause. FDA approved on February 26, 2013.
Uses
Ospemifene is a non-hormonal estrogen receptor modulator (SERM) used to treat moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy, due to menopause.
Ospemifene is used for the treatment of moderate to dyspareunia, a symptom of vulvar and vaginal atrophy, due to menopause.
Associated Conditions
Pharmacodynamics
The half maximal inhibitory concentration (IC50) for estrogen receptor (ER) alpha and beta are 0.8 μM and 1.7 μM, respectively. Ospemifene has potential uses in the management of osteoporosis in postmenopausal women. It interacts with osteoblasts and osteoclasts in such a way that it reduces bone turnover. It also has potential uses in the prevention of breast cancer. Studies suggest that ospemifene, in a dose-dependent manner, reduces the incidence of tumours.
Mechanism of Action
Ospemifene is a next generation SERM (selective estrogen receptor modulator) that selectively binds to estrogen receptors and either stimulates or blocks estrogen's activity in different tissue types. It has an agonistic effect on the endometrium.
Absorption
When a single oral dose of ospemifene 60 mg is given to postmenopausal women under fasted conditions, the pharmacokinetic parameters are as follows:
Tmax = 2 hours (range of 1 - 8 hours);
Cmax = 533 ng/mL;
AUC (0-inf) = 4165 ng•hr/mL.
When the same aforementioned dose is given to postmenopausal women under fed conditions, the pharmacokinetic parameters are as follows:
Tmax = 2.5 hours (1 - 6 hours);
Cmax = 1198 ng/mL;
AUC (0-inf) = 7521 ng•hr/mL.
Accumulation occurs following repeated doses.
Time to steady state = 9 days.
Although the bioavailability of ospemifene has not been formally evaluated, it is expected to have a low bioavailability because of its lipophilic nature.
Volume of Distribution
448 L
Protein Binding
>99% bound to serum proteins
Route of Elimination
Following an oral administration of ospemifene, approximately 75% and 7% of the dose was excreted in feces and urine, respectively. Less than 0.2% of the ospemifene dose was excreted unchanged in urine.
Half Life
Terminal half-life = 26 hours .
Clearance
Total body clearance = 9.16 L/hr.
Toxicity
Adverse reactions (≥1 percent) include: hot flush, vaginal discharge, muscle spasms, genital discharge, hyperhidrosis.
Food Interactions
- Take with food.
Dosage
Treatment of moderate to severe vaginal dryness, a symptom of vulvar and vaginal atrophy, due to menopause: 60 mg tablet with food once daily.
