Nonhormonal medication treatment of VMS

Gabapentin

Numerous randomized clinical trials have reported that gabapentin is superior to placebo for the treatment of VMS.¹⁵ In one trial, 420 patients with breast cancer and VMS were randomly assigned to 8 weeks of treatment with placebo, gabapentin 300 mg/day (G300), or gabapentin 900 mg/day (G900) in 3 divided doses.¹⁶ Following 8 weeks of treatment, reduction in hot-flash severity score among patients receiving placebo, G300, or G900 was 15%, 31%, and 46%, respectively. Fatigue and somnolence were reported more frequently among patients taking gabapentin 900 mg/day. In a small trial, 60 patients with VMS were randomized to receive placebo, conjugated estrogen (0.2625 mg/day),or gabapentin (target dose of 2,400 mg/day in 3 divided doses).¹⁷ Following 12 weeks of treatment, the patient-reported decrease in VMS for those taking placebo, estrogen, or gabapentin was 54%, 72%, and 71%, respectively.

High-dose gabapentin treatment was associated with side effects of headache and dizziness more often than placebo or estrogen. Although gabapentin is not a treatment for insomnia, in my practice if a menopausal patient has prominent and bothersome symptoms of sleep disturbance and mild VMS symptoms, I will consider a trial of low-dose gabapentin. Some experts recommend initiating gabapentin at a dose of 100 mgdaily before bedtime to assess the effectiveness of a low dose that seldom causes significant side effects.

^{ILLUSTRATION: ZONDA/ZAZA STUDIO/SHUTTERSTOCK}

Fezolinetant

In a study of genetic variation associated with VMS, investigators discovered that nucleic acid variation in the neurokinin 3 (NK3) receptor was strongly associated with the prevalence of VMS, suggesting that this receptor is in the causal pathway to menopausal VMS.¹⁸ Additional research demonstrated that the kisspeptin/neurokinin B/dynorphin (KNDy) neurons, which are involved in the control of hypothalamic thermoregulation, are stimulated by neurokinin B, acting through the NK3 receptor, and suppressed by estradiol. A reduction in hypothalamic estrogen results in unopposed neurokinin B activity, which stimulates KNDy neurons, destabilizing the hypothalamic thermoregulatory center, causing vasodilation, which is perceived as hot flashes and sweating followed by chills.¹⁹

Fezolinetant is a high-affinity NK3 receptor antagonist that blocks the activity of neurokinin B, stabilizing the hypothalamic thermoregulatory center, thereby suppressing hot flashes. It is approved by the FDA for the treatment of moderate to severe VMS due to menopause using a fixed dose of 45 mg daily.²⁰ In one clinical trial, 500 menopausal patients with bothersome VMS were randomly assigned to 12 weeks of treatment with placebo, fezolinetant 30 mg/day, or fezolinetant 45 mg/day. Following 12 weeks of treatment, the reported frequency rates of VMS among patients in the placebo, F30, and F45 groups were reduced by 43%, 61%, and 64%, respectively.²¹ In addition, following 12 weeks of treatment, the severity of VMS rates among patients in the placebo, F30, and F45 groups were reduced by 20%, 26%, and 32%, respectively.

Fezolinetant improved the quality of sleep and was associated with an improvement in patient-reported quality of life. Following 12 weeks of treatment, sleep quality among patients in the placebo, F30, and F45 groups was reported to be “much or moderately better” in 34%, 45%, and 54% of the patients, respectively.²¹ Similar results were reported in a companion study.²²

Fezolinetant is contraindicated for patients with liver cirrhosis or severe renal impairment (estimated glomerular filtration rate of < 30 mL/min/1.73 m2). Before initiating treatment, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin (total and direct). Fezolinetant should not be prescribed if any of these tests are greater than twice the upper limit of normal. These tests should be repeated at 3, 6, and 9 months, and if the patient reports symptoms or signs of liver injury (nausea, vomiting, jaundice). Fezolinetant is metabolized by CYP1A2 and should not be prescribed to patients taking strong CYP1A2 inhibitors. The most common side effects associated with fezolinetant treatment are abdominal pain (4.3%), diarrhea (3.9%), insomnia (3.9%), back pain (3.0%), and hepatic transaminase elevation (2.3%). Fezolinetant has not been thoroughly evaluated in patients older than age 65. Following an oral dose of the medication, the median maximum concentration is reached in 1.5 hours, and the half-life is estimated to be 10 hours.²⁰ Of all the medications discussed in this editorial, fezolinetant is the most expensive.

Effective VMS treatment improves overall health

Estrogen therapy is the gold standard treatment of VMS. However, many menopausal patients with bothersome VMS prefer not to take estrogen, and some have a medical condition that is a contraindication to estrogen treatment. The nonhormonal medication options for the treatment of VMS include escitalopram, paroxetine, gabapentin, and fezolinetant. Patients value the ability to choose the treatment they prefer, among all available hormonal and nonhormonal medication options. For mid-life women, effectively treating bothersome VMS is only one of many interventions that improves health. Optimal health is best achieved with²³:

• high-quality diet
• daily physical activity
• appropriate body mass index
• nicotine avoidance
• a healthy sleep schedule
• normal blood pressure, lipid, and glucose levels.

Women who have a high-quality diet; daily physical activity; an appropriate body mass index; and normal blood pressure, cholesterol, and glucose levels are estimated to live 9 disease-free years longer than other women.²⁴ ●