Inclusion Criteria:

A subject will be eligible for inclusion in this study only if all of the following criteria apply:

• Postmenopausal women aged 40 to 65 years old; postmenopausal defined as:

  i.Amenorrheic for at least 12 consecutive months* OR ii.At least 6 weeks post-surgical bilateral oophorectomy† with or without hysterectomy.

  *Note: Although duration of amenorrhea is initially determined by subject history at the time of the screening visit (Visit 1), menopausal status must be confirmed by demonstrating levels of follicle stimulating hormone (FSH) >40 mIU/mL (SI: >40 IU/L) and estradiol <35pg/mL (SI: <128pmol/L) at entry. Screening reports provided by the Central Laboratory must be carefully reviewed to determine menopause eligibility prior to conducting Visit 2 assessments. In the event a subject's menopause status has been clearly established (for example, the subject indicates she has been amenorrheic for 10 years), but FSH and/or estradiol levels are not consistent with a post-menopausal condition, determination of subject eligibility should be discussed with the study medical monitor.

  †For women who are surgically menopausal, a copy of the pathology report or a statement on letterhead from the subject's physician documenting both ovaries have been removed or biochemical evidence of post-menopausal status as noted above is required prior to conducting Visit 2 assessments.

• A minimum average frequency of seven daily moderate to extremely severe hot flashes or episodes of night sweats sufficient to cause the patient to seek treatment (these episodes must be documented during the baseline period and the subject must have recorded frequency and severity of symptoms for a minimum of eight days in order to be eligible for randomization). This average frequency will be calculated by summing the number of moderate, severe, and extremely severe VMS events during the baseline period and dividing by the total number of non-missing days during this period, with details related to the definition of non-missing days described in Section 6.3.1.
• BMI within the range 19 to 35 kg/m2, inclusive.
• Subject has provided signed and dated written informed consent before admission to the study.
• Subject is able to understand and comply with the protocol requirements, instructions, and protocol-stated restrictions.

Exclusion Criteria:

A subject will not be eligible for inclusion in this study if any of the following criteria apply:

• Investigator considers subject unfit for the study as a result of medical history, physical examination, or screening tests.

• Use of prescription or non-prescription drugs including:

  i.Hormone therapy (estrogen or estrogen/progestin combination or related products) within the following time period prior to conduct of Visit 1 assessments:

• 4 weeks for prior vaginal hormonal products (rings, creams, gels) or transdermal estrogen or estrogen/progestin products.
• 4 weeks for oral estradiol (e.g., micronized estradiol) or SERM products (e.g., raloxifene).
• 8 weeks for prior oral conjugated (equine or synthetic) estrogen or estrogen/progestin products or for prior intrauterine progestin therapy.
• 3 months for prior progestin implants or injectable estrogen.
• 6 months for prior estrogen pellet therapy or injectable progestin. ii.Use of putative therapies for VMS relief (e.g., selective serotonin reuptake inhibitors [SSRIs], serotonin-norepinephrine reuptake inhibitors [SNRIs], clonidine, gabapentin, tibolone, methyldopa, and the phytoestrogens black cohosh and red clover) within the past 30 days or 5 half-lives (whichever is longer) prior to conduct of Visit 1 assessments (note: half-lives will be provided in the SPM). Use of non-medication treatments for VMS, such as acupuncture and biofeedback, and other complementary or alternative therapies for VMS relief (with the exception of black cohosh and red clover which require a specified washout previously noted) must be discontinued at Visit 1.

iii.Use of weight loss drugs (e.g., phentermine, sibutramine, orlistat, rimonabant) within 3 months of the first dose of investigational product. Other complementary or alternative therapies for weight reduction must be discontinued at Visit 1. See SPM for listing.

iv.Use of pravastatin [Pravachol/Lipostat], rosuvastatin [Crestor], or pitavastatin [Livalo] within the past 30 days or 5 half-lives (whichever is longer) of the first dose of investigational product (note: half-lives will be provided in the SPM. Uses of other statins, for example simvastatin [Zocor], atorvastatin [Lipitor], fluvastatin [Lescol], lovastatin [Mevacor] is allowed).

v.Use of bupropion, orphenadrine [Norflex], cyclophosphamide, efavirenz, ifosfamide, or methadone (because of the potential for GSK232802 to inhibit CYP2B6), or use of paclitaxel, torsemide, amodiaquine, repaglinide, rosiglitazone, or pioglitazone (because of the potential for GSK232802 to inhibit CYP2C8) within the past 30 days or 5 half-lives (whichever is longer) of the first dose of investigational product (note: half-lives will be provided in the SPM).

Please note: Regardless of the reason for prescribing, use of the medications and therapies defined within Exclusion 2 above is prohibited. Concurrent administration of anti-depressants, anti-hypertensives, lipid-lowering therapies, etc. not specifically excluded above is allowed. See SPM for detailed listings and relevant half lives.

- Use of investigational drug within the past 30 days or 5 half-lives (whichever is longer) before the first dose of investigational product.

• Uterine disease or medical condition including:
• Bi-layer endometrial thickness greater than 5mm as determined by TVUS, or for women with a non-informative TVUS, a single layer thickness of greater than 3 mm determined by SIS; presence of fibroids that obscure evaluation of endometrium by TVUS;
• History of uterine cancer; evidence of endometrial hyperplasia or cancer as assessed by a screening endometrial biopsy. (Note: if a subject has insufficient tissue for diagnosis at screening, but bi-layer endometrial thickness by TVUS is ≤5mm or single wall thickness by SIS is ≤3mm, she may still be eligible for study entry if she meets the remaining inclusion/exclusion criteria);
• Evidence of an endometrial polyp with hyperplastic or malignant epithelium;
• Unexplained or unusual endometrial bleeding; or uterine surgery (other than hysterectomy*) within the past 6 months; *Note: hysterectomy must have been conducted at least 6 weeks prior to screening Visit 1. See also Inclusion criterion 1.
• Abnormal cervical Pap smear with evidence of cervical dysplasia greater than or equal to low grade squamous intraepithelial lesion (LSIL) or with a diagnosis of atypical squamous cells of undetermined significance (ASCUS) that is HPV High Risk positive, or glandular lesions including but not limited to atypical glandular cells of undetermined significance (AGUS), adenocarcinoma in situ (AIS) or malignancy
• History of breast or ovarian cancer. Any clinically significant findings on mammography suspicious of breast malignancy that would require additional clinical testing to rule out breast cancer (note: simple cysts confirmed by ultrasound are allowed).

Note: A screening mammogram is required unless the subject has had a mammogram performed within the last 12 months. If local mammography or medical management guidelines restrict the frequency with which mammograms can be performed, or impose age restrictions on the use of mammography, such that a subject may be unable to undergo the study-required screening mammogram, then these subjects must not be enrolled in the study. See Section 6.2.7.

- Cardiovascular conditions including: i. Systolic blood pressure (BP) outside the range 80 to 150 mmHg, diastolic BP outside the range 50 to 90 mmHg, and/or heart rate outside the range 40 to 100 bpm. Subjects with mild to moderate hypertension who are controlled on a stable antihypertension regimen may be enrolled if they meet the inclusion/exclusion criteria.

ii. Symptomatic or asymptomatic arrhythmia of any clinical significance. iii. Any clinically significant abnormality identified on the screening 12-lead ECG. Subjects with QTc prolongation (QTc interval >450msec) will be excluded.

iv. Has a documented history (within the last year) of myocardial infarction, angina, or has undergone coronary artery bypass surgery and/or percutaneous transluminal coronary angioplasty (PTCA).

v. History of venous or arterial thromboembolic disease (e.g., deep vein thrombosis, pulmonary embolism, stroke), history of known coagulopathy or abnormal coagulation factors; increased thrombotic risk as evidenced by positive APC resistance (APCR) evaluated at screening.

- Has a documented history of hepatobiliary disease or hepatic enzyme elevation including any one of the following: i.ALT or direct (conjugated) bilirubin values 1.5-fold higher than the ULN at screening.

ii.Fasting triglycerides >400mg/dL (SI: >4.52mmol/L) at screening. If a subject is receiving a lipid-lowering therapy, then she must be on a stable dose for at least 1 month before screening.

• Has an abnormal thyroid function test assessed by TSH at screening (TSH <0.1uU/mL or >10uU/mL [SI: <0.1mU/L or >10mU/L] ).

Note: If the TSH is mildly out of range at screening (TSH < 15U/mL), the subject may have her dose adjusted (if already on exogenous therapy) or have therapy initiated as deemed appropriate by the subject's physician, followed by a 3-4 week period to allow adequate equilibration. The TSH may then be re-assayed for eligibility purposes after this stabilization period has been completed. The subject should not progress through subsequent V2 assessments until re-assay demonstrates the TSH is within acceptable protocol-defined limits. Subjects with suppressed levels of TSH, <0.1U/mL, may have dose adjustment if free T4 is in normal range, and they are on exogenous thyroxine therapy.

• Has either a previous disease or current medical condition, which as judged by the investigator, may affect the interpretation of efficacy or safety data or which otherwise contraindicates participation in a clinical study with a new chemical entity. These diseases include, but are not limited to, cardiovascular disease, malignancy*, complex ovarian pathology, hepatic disease, renal disease, hematological disease, neurological disease, or endocrine disease. A subject with diabetes may be included if her diabetes is well controlled (i.e., HbA1c level is less than 8% at screening).

  *Note: Any history of malignancy within the past 5 years is exclusionary with the exception of basal cell (excluded if within the prior 2 years) or squamous cell (excluded if within the prior one year) carcinoma of the skin. Subjects with a prior malignancy who have had no evidence of disease for at least the past 5 years are eligible. Note that this timeframe does not apply to uterine, breast, and ovarian cancers which are defined in Exclusions 4 and 5 above.

• History of alcohol or substance abuse or dependence in the 12 months before screening as determined by the investigator.
• Positive results for hepatitis B surface antigen or hepatitis C antibodies as evaluated at screening Visit 1. Known history of HIV.
• Donation of blood in excess of 500mL within a 56-day period before screening.
• History or presence of allergy to the investigational product or drugs of this class (e.g., raloxifene), or history of drug or other allergy that, in the opinion of the physician responsible, contraindicates their participation.