Last reviewed 2026-04-20 · How we verify

Osphena (OSPEMIFENE)

Osphena works by binding to estrogen receptors, specifically targeting estrogen receptor beta, to provide relief from symptoms of atrophic vulva and dyspareunia.

Osphena (osmefinifene) is a small molecule estrogen agonist/antagonist developed by Shionogi Inc and currently owned by Duchesnay. It targets estrogen receptor beta to treat atrophic vulva and dyspareunia. Osphena was FDA-approved in 2013 and is available as a branded medication. The commercial status of Osphena is not off-patent, but generic manufacturers are available. Key safety considerations include the potential for endometrial cancer risk in postmenopausal women.

At a glance

Mechanism of action

OSPHENA is an estrogen receptor agonist/antagonist with tissue selective effects. Its biological actions are mediated through binding to estrogen receptors. This binding results in activation of estrogenic pathways in some tissues (agonism) and blockade of estrogenic pathways in others (antagonism).

Approved indications

• Atrophic vulva
• Dyspareunia

Boxed warnings

• WARNING: ENDOMETRIAL CANCER and CARDIOVASCULAR DISORDERS WARNING: ENDOMETRIAL CANCER and CARDIOVASCULAR DISORDERS See full prescribing information for complete boxed warning. OSPHENA is an estrogen agonist/antagonist with tissue selective effects. In the endometrium, OSPHENA has estrogen agonistic effects. There is an increased risk of endometrial cancer in a woman with a uterus who uses unopposed estrogens. Perform adequate diagnostic measures, including directed and random endometrial sampling when indicated, to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital bleeding [see Warnings and Precautions (5.2) ]. Estrogen-alone therapy has an increased risk of stroke and deep vein thrombosis (DVT). OSPHENA 60 mg had cerebral thromboembolic and hemorrhagic stroke incidence rates of 1.13 and 3.39 per thousand women years, respectively vs. 3.15 and 0 per thousand women years, respectively with placebo. For deep vein thrombosis, the incidence rate for OSPHENA 60 mg is 2.26 per thousand women years (2 reported cases) vs. 3.15 per thousand women years (1 reported case) with placebo [see Warnings and Precautions (5.1) ]. Endometrial Cancer OSPHENA is an estrogen agonist/antagonist with tissue selective effects. In the endometrium, OSPHENA has estrogen agonistic effects. There is an increased risk of endometrial cancer in a woman with a uterus who uses unopposed estrogens. Perform adequate diagnostic measures, including directed and random endometrial sampling when indicated, to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital bleeding [see Warnings and Precautions (5.2) ]. Cardiovascular Disorders In the clinical trials for OSPHENA (duration of treatment up to 15 months), the incidence rates of thromboembolic and hemorrhagic stroke were 1.13 and 3.39 per thousand women years, respectively in the OSPHENA 60 mg treatment group and 3.15 and 0 with placebo [see Warnings and Precautions (5.1) ]. The incidence of DVT was 2.26 per thousand women years (2 reported cases) in the OSPHENA 60 mg treatment group and 3.15 per thousand women years (1 reported case) with placebo [see Warnings and Precautions (5.1) ]. OSPHENA should be prescribed for the shortest duration consistent with treatment goals and risks for the individual woman. Increased risks of stroke and deep vein thrombosis (DVT) are reported in postmenopausal women (50 to 79 years of age) during 7.1 years of treatment with daily oral conjugated estrogens (CE) [0.625 mg]-alone, relative to placebo as part of the Women's Health Initiative (WHI) [see Warnings and Precautions (5.1) ].

Common side effects

• Hot flush
• Vaginal discharge
• Hyperhidrosis
• Muscle spasms
• Headaches
• Night sweats
• Vaginal hemorrhage
• Deep vein thrombosis
• Pulmonary embolism
• Rash
• Pruritus
• Urticaria

Drug interactions

• fluconazole
• voriconazole

Key clinical trials

• Effects of Ospemifene on Brain Activation Patterns in Women With Sexual Interest-arousal Disorders (PHASE4)
• Study to Evaluate Ospemifene in Patients With Moderate to Severe Vaginal Dryness Due to Menopause (PHASE3)
• Vulvoscopy Changes of the Vulva, Vestibule and Vagina With Daily Ospemifene in Women With Dyspareunia From VVA (PHASE4)
• Long-Term Safety of 30 mg and 60 mg Oral Daily Dose of Ospemifene in the Treatment of Vulvar and Vaginal Atrophy (VVA) in Postmenopausal Women With Intact Uterus (PHASE3)
• Long-Term Safety of Ospemifene 60 mg Oral Daily Dose for the Treatment of Vulvar and Vaginal Atrophy (VVA) in Postmenopausal Women Without a Uterus (PHASE3)
• A Clinical Study to Evaluate the Safety of Ospemifene (PHASE3)
• Efficacy and Safety of Ospemifene in the Treatment of Moderate to Severe Vaginal Dryness and Vaginal Pain Associated With Sexual Activity (PHASE3)
• Ospemifene vs. Conjugated Estrogens in the Treatment of Postmenopausal Sexual Dysfunction (PHASE4)

Patents

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Osphena CI brief — competitive landscape report
• Osphena updates RSS · CI watch RSS
• Duchesnay portfolio CI