Study of Gabapentin Extended Release (G-ER) in the Treatment of Vasomotor (Hot Flashes/Hot Flushes) Symptoms in Postmenopausal Women

The primary study objective is to assess the efficacy of G-ER dosed in either of the following regimens:

• G-ER 1200 mg daily (single evening dose)
• G-ER 1800 mg daily (dosed asymmetrically; 600 mg in AM/1200 mg in PM) compared to placebo in reducing the average daily frequency and severity score of moderate to severe hot flashes in postmenopausal women after 4 weeks and 12 weeks of treatment with a stable dose, compared with the baseline week.

Inclusion criteria

• Postmenopausal women aged 18 to 70 years experiencing ≥7 moderate to severe hot flashes per day (or ≥50 per week) accompanied by sweating during previous 30 days or longer.
• Had amenorrhea for ≥12 months, amenorrhea for 6 to 12 months with serum follicle-stimulating hormone (FSH) levels >40 mIU/mL, or was ≥6 weeks postsurgical bilateral oophorectomy with or without hysterectomy.
• Willing to discontinue the following: vaginal hormonal products; transdermal or oral estrogen or estrogen/progestin combination; intrauterine progestin; progestin implants; injectable estrogen; topical progesterone cream.
• Had to have daily average of ≥7 moderate to severe hot flashes and had to complete ≥4 days of diary entries during baseline week to be randomized.
• If treated with antidepressants, could not have had any changes in drug doses during past month.

Other Inclusions apply.

Exclusion criteria

• Patient treated with a gonadotrophin releasing hormone agonist, anti-estrogens, or aromatase inhibitors within 2 months prior to study entry.
• Patient treated with estrogen pellets or progestin injectable drugs within 6 months prior to study entry.
• Patient experience only nighttime hot flashes or worked night shifts on a regular basis.
• Patient was concurrently treated with gabapentin for other indications. If patient was using gabapentin for treatment of hot flashes, she could be screened after a 7-day washout period provided hot flashes returned.
• Patient had previously experienced dose-limiting adverse events that prevented titration of gabapentin to an effective dose.
• Patient had a hypersensitivity to gabapentin.
• Patient was in an immunocompromised state.
• Patient had a malignancy other than basal cell carcinoma within 2 years prior to study entry.
• Patient had gastric reduction surgery, severe chronic diarrhea, chronic constipation, uncontrolled irritable bowel syndrome, uncontrolled inflammatory bowel disease, or unexplained weight loss.
• Patient had clinically significant abnormal chemistry or hematology results, or calculated glomerular filtration rate <60 mL/min.
• Patient had history of substance abuse within year prior to study entry.
• Patient was concurrently taking morphine.
• Patient had history of chronic hepatitis B or C, hepatitis within 3 months prior to study entry, or history of human immunodeficiency virus.

Other Exclusions apply.