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Ospemifene Side Effects

Medically reviewed by Last updated on Nov 7, 2023.

Applies to ospemifene: oral tablet.


Oral route (Tablet)

Endometrial CancerOspemifene is an estrogen agonist/antagonist with tissue selective effects. In the endometrium, ospemifene has estrogen agonistic effects. There is a potential increased risk of endometrial cancer in a woman with a uterus who uses unopposed estrogens. Adequate diagnostic measures, including directed and random endometrial sampling when indicated, should be undertaken to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital bleeding.Cardiovascular DisordersIn the clinical trials for ospemifene (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 ospemifene 60 mg treatment group and 3.15 and 0 with placebo. The incidence of DVT was 2.26 per thousand women years (2 reported cases) in the ospemifene 60 mg treatment group and 3.15 per thousand women years (1 reported case) with placebo. Ospemifene should be prescribed for the shortest duration consistent with treatment goals and risks for the individual woman.There is a reported increased risk of stroke and deep vein thrombosis (DVT) in postmenopausal women (50 to 79 years of age) who received daily oral conjugated estrogens (CE) [0.625 mg]-alone therapy over 7.1 years as a part of the Women's Health Initiative (WHI).

Serious side effects of Ospemifene

Along with its needed effects, ospemifene may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking ospemifene:

Less common

Incidence not known

Other side effects of Ospemifene

Some side effects of ospemifene may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

For Healthcare Professionals

Applies to ospemifene: oral tablet.


The more commonly reported adverse events have included hot flush, vaginal discharge, muscle spasms, genital discharge, and hyperhidrosis.


Common (1% to 10%): Hot flashes

Uncommon (0.1% to 1%): Hemorrhagic stroke, deep vein thrombosis (DVT)

Rare (less than 0.1%): Thromboembolic stroke, myocardial infarction

Postmarketing reports: Thrombosis, pulmonary embolism[Ref]

In the clinical trials, the incidence rates of thromboembolic and hemorrhagic stroke in women receiving this drug were 1.13 and 3.39 per thousand women years, compared with 3.15 and 0 per thousand women years in placebo. Two cases of myocardial infarction occurred in women receiving this drug and 2 cases of deep vein thrombosis.

This drug has been reported to initiate or increase the occurrence of hot flashes in some women. In phase 2/3 clinical trials, about 1% of women discontinue this drug due to hot flushes.[Ref]


Postmarketing reports: Pulmonary embolism


Postmarketing reports: Endometrial hyperplasia, endometrial cancer


Common (1% to 10%): Vaginal discharge, genital discharge, proliferative endometrium, endometrial thickening

Uncommon (0.1% to 1%): Uterine polyps

Rare (less than 0.1%): Simple hyperplasia without atypia[Ref]

During clinical trials, one case of simple hyperplasia without atypia occurred. Endometrial thickening of 5 mm or greater was observed in women taking 60 mg/day at a rate of 60.1 per thousand compared to 21.2 per thousand in the placebo group. Any type of proliferative (weakly plus active plus disordered) endometrium was reported at 86.1 per thousand in women taking this drug compared with 13.3 per thousand for placebo. Uterine polyps occurred at an incidence of 5.9 per thousand compared with 1.8 per thousand in those receiving this drug and placebo, respectively. Endometrial cancer was not reported in trials up to 52 weeks long.[Ref]


Common (1% to 10%): Hyperhidrosis

Postmarketing reports: Rash, rash erythematous, rash generalized, pruritus, urticaria[Ref]


Common (1% to 10%): Muscle spasms[Ref]


Postmarketing reports: Allergic conditions including hypersensitivity, angioedema

Nervous system

Postmarketing reports: Headache


1. Product Information. Osphena (ospemifene). Shionogi USA Inc. 2013.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.