May 30, 2017
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"March 14, 2013 -- Hormone replacement therapy is the most effective treatment for symptoms like hot flashes, and the benefits are likely to outweigh the risks, major medical societies say.

The statement was published in the April issue "...



Side Effects


The following serious adverse reactions are discussed elsewhere in the labeling:

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of OSPHENA has been assessed in nine phase 2/3 trials (N=1892) with doses ranging from 5 to 90 mg per day. The duration of treatment in these studies ranged from 6 weeks to 15 months. Most women (N=1370) had a treatment period of at least 12 weeks, 409 had at least 52 weeks (1 year) of exposure.

The incidence rates of thromboembolic and hemorrhagic stroke were 0.72 per thousand women (1 reported case of thromboembolic stroke) and 1.45 per thousand women (2 reported cases of hemorrhagic stroke), respectively in OSPHENA 60 mg treatment group and 1.04 and 0 per thousand women, respectively in placebo. The incidence of deep vein thrombosis (DVT) was 1.45 per thousand women in OSPHENA 60 mg treatment group (2 reported cases of DVT) and 1.04 (1 case of DVT) in placebo.

Table 1 lists adverse reactions occurring more frequently in the OSPHENA 60 mg treatment group than in placebo and at a frequency ≥1%.

Table 1: Adverse Reactions Reported More Common in the OSPHENA Treatment Group (60 mg Once Daily) and at Frequency ≥1.0% in the Double-Blind, Controlled Clinical Trials with OSPHENA vs. Placebo

  Ospemifene 60 mg
(N=1242) %
(N=958) %
Vascular Disorders
  Hot flush 7.5 2.6
Reproductive System and Breast Disorders
  Vaginal discharge 3.8 0.3
  Genital discharge 1.3 0.1
Musculoskeletal and Connective Tissue Disorders
  Muscle spasms 3.2 0.9
Skin and Subcutaneous Tissue Disorders
  Hyperhidrosis 1.6 0.6

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of ospemifene. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Immune System Disorders: allergic conditions including hypersensitivity, angioedema

Skin and Subcutaneous Tissue Disorders: rash, rash erythematous, rash generalized, pruritus, urticaria

Read the Osphena (ospemifene tablets) Side Effects Center for a complete guide to possible side effects


OSPHENA is primarily metabolized by CYP3A4 and CYP2C9. CYP2C19 and other pathways contribute to the metabolism of ospemifene.

Estrogens And Estrogen Agonist/Antagonist

OSPHENA should not be used concomitantly with estrogens and estrogen agonists/antagonists. The safety of concomitant use of OSPHENA with estrogens and estrogen agonists/antagonists has not been studied.


Fluconazole, a moderate CYP3A / strong CYP2C9 / moderate CYP2C19 inhibitor, should not be used with OSPHENA. Fluconazole increases the systemic exposure of ospemifene by 2.7-fold. Administration of fluconazole with ospemifene may increase the risk of OSPHENA-related adverse reactions [see CLINICAL PHARMACOLOGY].


Rifampin, a strong CYP3A4 / moderate CYP2C9 / moderate CYP2C19 inducer, decreases the systemic exposure of ospemifene by 58%. Therefore, co-administration of OSPHENA with drugs such as rifampin which induce CYP3A4, CYP2C9 and/or CYP2C19 activity would be expected to decrease the systemic exposure of ospemifene, which may decrease the clinical effect [see CLINICAL PHARMACOLOGY].


Ketoconazole, a strong CYP3A4 inhibitor increases the systemic exposure of ospemifene by 1.4-fold. Administration of ketoconazole chronically with ospemifene may increase the risk of OSPHENA-related adverse reactions [see CLINICAL PHARMACOLOGY].


Repeated administration of ospemifene had no effect on the pharmacokinetics of a single 10 mg dose of warfarin. No study was conducted with multiple doses of warfarin. The effect of ospemifene on clotting time such as the International Normalized Ratio (INR) or prothrombin time (PT) was not studied [see CLINICAL PHARMACOLOGY].

Highly Protein-Bound Drugs

Ospemifene is more than 99% bound to serum proteins and might affect the protein binding of other drugs. Use of OSPHENA with other drug products that are highly protein bound may lead to increased exposure of either that drug or ospemifene [see CLINICAL PHARMACOLOGY].

Multiple Enzyme Inhibition

Co-administration of OSPHENA with a drug known to inhibit CYP3A4 and CYP2C9 isoenzymes may increase the risk of OSPHENA-related adverse reactions.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 3/13/2015

Side Effects

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