The purpose of this study is to assess the efficacy and safety of 4 doses of desvenlafaxine-233 sustained release (DVS-233 SR) as compared to placebo for the treatment of moderate to severe vasomotor symptoms associated with menopause, as well as its influence on sleep parameters and other health outcomes indicators.

Inclusion Criteria:

1. Generally healthy, postmenopausal women; at least 12 months of spontaneous amenorrhea or at least 6 months of spontaneous amenorrhea with serum FSH levels > 40 mIU/mL or at least 6 weeks postsurgical bilateral oophorectomy (with or without hysterectomy).

2. Minimum of 7 moderate to severe hot flushes per day or 50 moderate to severe hot flushes per week at screening:

   • Moderate hot flush: warm sensation with sweating, does not disrupt activity.
   • Severe hot flush: hot sensation with sweating, disrupts activity.

3. Subjects must have body mass index (BMI) less than or equal to 40 using the nomograph for BMI.

Exclusion Criteria:

1. Hypersensitivity to venlafaxine (Effexor or Effexor XR).
2. Use of oral estrogen-, progestin-, androgen-, or SERM-containing drug products within 8 weeks prior to screening; use of transdermal hormone products within 8 weeks prior to screening; use of vaginal hormone products (rings, creams, gels) within 4 weeks prior to screening; use of intrauterine progestins within 8 weeks prior to screening; use of progestin implants or estrogen injectables within 3 months prior to screening; use of estrogen pellet or progestin injectables within 6 months prior to screening.
3. History of a seizure disorder other than a single childhood febrile seizure.