Gabapentin's effects on hot flashes and hypothermia

Contemporary Non-hormonal Therapies for the Management of Vasomotor Symptoms Associated with Menopause: A Literature Review

Nearly 75% of all menopausal women experience bothersome vasomotor symptoms including hot flushes and night sweats. Yet vasomotor symptoms continue to be an undertreated and underdiagnosed symptom of menopause which can negatively affect a woman's overall quality of life. While hormone therapy has been widely utilized to ameliorate hot flushes, not all women are candidates for use, especially those with increased risk of cardiovascular disease, thromboembolic disease, and/or women at an increased risk of certain hormone-dependent cancers. The current literature provides strong evidence for non-hormonal therapies in women who experience vasomotor symptoms. This article reviews the evidence for the use of non-hormonal pharmacologic therapies for the treatment of menopausal symptoms including antidepressants, gabapentinoids, clonidine and anticholinergics. We also review data on emerging therapies including the latest evidence on neurokinin-1 and -3 antagonists. These therapies should be considered when hormonal options are contraindicated and/or not preferred by the patient. While there are many options available, clinicians should individualize therapy based on the patient's needs and goals while mitigating bothersome side effects.

Pharmacotherapeutic options for the treatment of menopausal symptoms

Introduction: Menopausal symptoms can be very overwhelming for women. Over the years, many pharmacotherapeutic options have been tested, and others are still being developed. Hormone therapy (HT) is the most efficient therapy for managing vasomotor symptoms and related disturbances. The term HT comprises estrogens and progestogens, androgens, tibolone, the tissue-selective estrogen complex (TSEC), a combination of bazedoxifene and conjugated estrogens, and the selective estrogen receptor modulators, such as ospemifene. Estrogens and progestogens and androgens may differ significantly for chemical structure and can be delivered through different routes, thereby displaying various pharmacological and clinical properties. Tibolone, TSEC and SERM also exhibit unique pharmacodynamics that can be exploited to obtain distinctive therapeutic effects. Non-hormonal options fall mainly into the selective serotonin reuptake inhibitor (SSRI) and selective noradrenergic reuptake inhibitor (SNRI), GABA-analogue drug classes.Areas covered: Herein, the authors describe the pharmacokinetics and pharmacodynamics of hormonal (androgens, estrogens, progestogens, tibolone, TSEC, SERMs) and non-hormonal (SSRIs, SNRIs, Gabapentin, Pregabalin, Oxybutynin, Neurokinin antagonists) treatments for menopausal symptoms and report essential clinical trial data in humans.Expert opinion: Patient tailoring of treatment is key to managing symptoms of menopause. Physicians must have in-depth knowledge of the pharmacology of compounds to tailor therapy to the individual patient's characteristics and needs.

Efficacy and safety of gabapentin and pregabalin in patients with vasomotor symptoms: a systematic review and meta-analysis

OBJECTIVE

Vasomotor symptoms are common among postmenopausal women and patients receiving hormone deprivation therapies, and emerging studies are exploring gabapentin's and pregabalin's effects as nonhormonal treatment options. We aimed to assess the efficacy and safety of these 2 drugs.

DATA SOURCES

Based on a preregistered protocol (Prospective Register of Systematic Reviews -CRD42019133650), we searched 10 databases (PubMed, Embase, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Chinese Biological Medical Literature, Chinese National Knowledge Infrastructure, Chinese Journals Full-text Database [VIP], and Wanfang) as well as the World Health Organization international clinical trials registry platform and reference lists of related literatures.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials and randomized crossover studies exploring gabapentin and pregabalin among women patients with vasomotor symptoms were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement was followed. Two reviewers independently selected studies, assessed bias, and extracted data. Mean difference and standardized mean difference with 95% confidence intervals were assessed by random-effects models. Heterogeneities were assessed by I² statistics, and the quality of evidence was evaluated by the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Nineteen randomized controlled trials and 2 randomized crossover trials reporting results from 3519 participants were included. Gabapentin could reduce hot flash frequency (mean difference, -1.62, 95% confidence interval, -1.98 to -1.26 after 4 weeks; mean difference, -2.77, 95% confidence interval, -4.29 to -1.24 after 12 weeks) and composite score (standardized mean difference, -0.47, 95% confidence interval, -0.71 to -0.23 after 4 weeks; standardized mean difference, -0.77, 95% confidence interval, -1.15 to -0.40 after 12 weeks) compared with placebo. Both menopausal participants and patients with breast cancer benefited from treatment. Higher risks of dizziness and somnolence were found in the gabapentin group than in the control group (risk ratio, 4.45, 95% confidence interval, 2.50-7.94; risk ratio, 3.29, 95% confidence interval, 1.97-5.48, respectively). Estrogen was more effective in reducing hot flash frequency than gabapentin. No statistically significant difference in reduction of hot flash severity score was found between gabapentin and antidepressants. The trials comparing gabapentin or pregabalin with the other interventions were too limited to make a conclusion.

CONCLUSION

Favorable effects of gabapentin in relieving vasomotor symptoms were observed, compared with controls, but were less effective than those of estrogen. Evidence supporting the therapeutic effect of pregabalin is still lacking.

Gabapentin for the treatment of hot flushes in menopause: a meta-analysis

OBJECTIVE

Gabapentin is used to treat vasomotor symptoms (VMS) in postmenopausal women with contraindications to hormonal therapy or who prefer alternatives. We investigated the efficacy and tolerability of gabapentin for treating menopausal hot flushes via a meta-analysis.

METHODS

We searched the PubMed, MEDLINE, EMBASE, and CENTRAL databases for English-language articles published until June, 2018. The following search terms were used: "menopause," "hot flushes," "vasomotor symptoms," "gabapentin," and "non-hormonal therapy." Primary outcomes were frequency, duration, and composite score of hot flushes. Secondary outcomes were adverse effects and dropout rate. We estimated the standardized mean difference (SMD) and combined odds ratio (OR) using fixed or random-effects models, depending on study heterogeneity. Subgroup and meta-regression analyses of gabapentin dosage were performed.

RESULTS

We included seven randomized controlled trials that compared single-agent gabapentin with placebo for treating hot flushes in the meta-analysis. Women who received gabapentin reported a significantly greater reduction in the frequency (SMD 2.99 [95% confidence interval 2.01-3.98], P < 0.001), duration (0.89 [0.49-1.30], P < 0.001), and composite score (2.31 [1.50-3.11], P < 0.001) of hot flushes. Adverse events were significantly more frequent among those taking gabapentin than among those taking the placebo (OR 1.58 [0.98-2.18], P < 0.001; and 1.19 [0.43-1.95], P = 0.002 for dizziness and unsteadiness, respectively).

CONCLUSIONS

Gabapentin could be used to treat VMS in postmenopausal women with contraindications to hormonal therapy. Future studies should investigate the lowest effective dose of gabapentin to minimize adverse effects. : Video Summary:http://links.lww.com/MENO/A521.

Is complementary and alternative therapy effective for women in the climacteric period?

Vasomotor symptoms start about 2 years prior to menopause in women who are approaching menopause, and early menopause symptoms appear including emotional disturbance and anxiety, followed by physical changes such as vaginal dryness, urinary incontinence and skin wrinkles. As time progresses, osteoporosis, cardiovascular diseases, and dementia occur consecutively. Hormone therapy is primarily considered for the relief of menopause symptoms in postmenopausal women. However, as hormone replacement has emerged as a therapy that increases the potential risk of thrombosis, cerebral infarction and breast cancer, complementary and alternative medicine has drawn much attention. This study aimed to examine the types and effects of evidence-based complementary and alternative therapies that are currently used.

A systematic review of non-hormonal treatments of vasomotor symptoms in climacteric and cancer patients

The cardinal climacteric symptoms of hot flushes and night sweats affect 24-93% of all women during the physiological transition from reproductive to post-reproductive life. Though efficacious, hormonal therapy and partial oestrogenic compounds are linked to a significant increase in breast cancer. Non-hormonal treatments are thus greatly appreciated.

This systematic review of published hormonal and non-hormonal treatments for climacteric, and breast and prostate cancer-associated hot flushes, examines clinical efficacy and therapy-related cancer risk modulation.

A PubMed search included literature up to June 19, 2014 without limits for initial dates or language, with the search terms, (hot flush* OR hot flash*) AND (clinical trial* OR clinical stud*) AND (randomi* OR observational) NOT review). Retrieved references identified further papers. The focus was on hot flushes; other symptoms (night sweats, irritability, etc.) were not specifically screened. Included were some 610 clinical studies where a measured effect of the intervention, intensity and severity were documented, and where patients received treatment of pharmaceutical quality. Only 147 of these references described studies with alternative non-hormonal treatments in post-menopausal women and in breast and prostate cancer survivors; these results are presented in Additional file 1.

The most effective hot flush treatment is oestrogenic hormones, or a combination of oestrogen and progestins, though benefits are partially outweighed by a significantly increased risk for breast cancer development.

This review illustrates that certain non-hormonal treatments, including selective serotonin reuptake inhibitors, gabapentin/pregabalin, and Cimicifuga racemosa extracts, show a positive risk-benefit ratio.

Key points

Several non-hormonal alternatives to hormonal therapy have been established and registered for the treatment of vasomotor climacteric symptoms in peri- and post-menopausal women.

There are indications that non-hormonal treatments are useful alternatives in patients with a history of breast and prostate cancer. However, confirmation by larger clinical trials is required.

Novel ligands balance estrogen receptor β and α agonism for safe and effective suppression of the vasomotor response in the ovariectomized female rat model of menopause

Vasomotor thermo-dysregulation (hot flashes) are an often debilitating symptom of menopause. Effective treatment is achieved primarily through activation of the estrogen receptor (ER)α with estrogens but is also associated with increased risk for breast and uterine cancer. In this study, we have tested novel compounds lacking the B ring of 17-hydroxy-β-estradiol (E2) (A-CD compounds) with differing ratios of ERα:ERβ binding affinities for the ability to reduce diurnal/nocturnal tail-skin temperatures (TSTs) in the ovariectomized female rat menopausal hot flash model. Normal mammary tissue expresses the predominantly antiproliferative ERβ. Therefore, we hypothesized that a preferential ERβ agonist with fractional ERα activity would safely reduce TSTs. The A-CD compound, L17, is a preferential ERβ agonist that has a ratio of ERβ:ERα binding affinity relative to E2 of 9.3 (where ERβ:ERα for E2, 1.0). In the ovariectomized rat, daily administration of low doses (1 mg/kg) of the A-CD compound TD81 (ERα:ERβ relative affinity, 15.2) was ineffective in temperature regulation, whereas L17 showed a trend toward TST reduction. Both E2 and the A-CD compound, TD3 (ERβ:ERα relative affinity, 5.0), also reduced TSTs but had marked proliferative effects on mammary and uterine tissues. At 2 mg/kg, L17 strongly reduced TSTs even more effectively than E2 but, importantly, had only minimal effect on uterine weight and mammary tissues. Both E2- and L17-treated rats showed similar weight reduction over the treatment period. E2 is rapidly metabolized to highly reactive quinones, and we show that L17 has 2-fold greater metabolic stability than E2. Finally, L17 and E2 similarly mediated induction of c-fos expression in neurons within the rat thermoregulatory hypothalamic median preoptic nucleus. Thus, the A-CD compound, L17, may represent a safe and effective approach to the treatment of menopausal hot flashes.

Non-hormonal management of vasomotor symptoms

Vasomotor symptoms are the most common indication for the prescription of hormone replacement therapy since it is effective in over 80% of cases. In 1995, 37% of American women took hormone replacement therapy, principally for this purpose. However, following the publication of results from the Women's Health Initiative, as many as half of these women in the US and in the UK and New Zealand discontinued hormone therapy. Discontinuation of estrogen is often accompanied by a return of vasomotor symptoms; however, only a small number (18%) of women report restarting hormone therapy. Alternatives are available, but limited knowledge on etiology and mechanisms of hot flushing represents a major obstacle for the development of new, targeted, non-hormonal treatments, and no current alternatives are as effective as estrogen.

Risk factors, pathophysiology, and treatment of hot flashes in cancer

Hot flashes are prevalent and severe symptoms that can interfere with mood, sleep, and quality of life for women and men with cancer. The purpose of this article is to review existing literature on the risk factors, pathophysiology, and treatment of hot flashes in individuals with cancer. Electronic searches were conducted to identify relevant English-language literature published through June 15, 2012. Results indicated that risk factors for hot flashes in cancer include patient-related factors (eg, age, race/ethnicity, educational level, smoking history, cardiovascular risk including body mass index, and genetics) and disease-related factors (eg, cancer diagnosis and dose/type of treatment). In addition, although the pathophysiology of hot flashes has remained elusive, these symptoms are likely attributable to disruptions in thermoregulation and neurochemicals. Therapies that have been offered or tested fall into 4 broad categories: pharmacological, nutraceutical, surgical, and complementary/behavioral strategies. The evidence base for this broad range of therapies varies, with some treatments not yet having been fully tested or showing equivocal results. The evidence base surrounding all therapies is evaluated to enhance hot flash treatment decision-making by clinicians and patients.

Comparison of Gabapentin with Estrogen for treatment of hot flashes in post-menopausal women

OBJECTIVE

Various non-hormonal agents have been used for the treatment of hot flashes in women with menopause. Some studies have reported that gabapentin appears to be an effective and well-tolerated treatment modality. The aim of this study was to evaluate whether the treatment with gabapentin is effective in reducing hot flash frequency and severity and also to compare gabapentin 100 mg/day, 300 mg/day and conjugated estrogen in this regards.

METHODS

In this comparative clinical trial, 100 post-menopausal women attending outpatient clinics of Isfahan University hospitals were included from April 2008 to February 2009. Participants randomly received gabapentin 300 mg/day, gabapentin 100 mg/day, or conjugated estrogen 0.625 mg/day for 12 weeks. Frequency and severity of hot flashes and adverse effects were compared among the three groups.

FINDINGS

From all, 16 participants dropped out. There were no significant differences among the groups before intervention in terms of age, body mass index and baseline hot flash frequency and severity. Hot flash diaries were used to record the frequency and severity of hot flashes. After the treatment period, there was a significant decrease in both severity and frequency of hot flashes in all three groups. Post-hoc analyses showed that the frequency and severity of hot flashes were significantly lower in those who received gabapentin 300 mg/day or estrogen 0.625 mg/day compared to those who received gabapentin 100 mg/day. There was not statistically significant difference between those who received gabapentin 300 mg/day and those who received estrogen. Very few adverse effects, mostly gastrointestinal discomfort were observed in both gabapentin groups (8%).

CONCLUSION

Gabapentin 300 mg/day could be useful to relieve hot flashes in women for whom hormone therapy is not suitable or when hot flashes do not respond to other therapies. Further researches are needed to determine the efficacy of gabapentin use for longer periods or at higher doses.

New generation nonhormonal management for hot flashes

Hot flashes are very common in women in menopause and can have a detrimental effect on quality of life. Hormone therapy (estrogen with or without progestin) remains the gold standard treatment for hot flashes, but concerns for the risk of hormone therapy have resulted in its decline and a demand for nonhormonal treatments with demonstrated efficacy for hot flashes. Several nonhormonal therapies have been tested in randomized placebo-controlled trials including nonpharmacologic approaches and pharmacologic nonhormonal agents. Among them, two classes of nonhormonal medications have been demonstrated to effectively alleviate hot flashes: γ-aminobutyric acid (GABA) analogs and selective serotonin reuptake inhibitors (SSRIs). This article discusses the superior efficacy of the newer nonhormonal prescriptions for the treatment of hot flashes when compared with estrogen replacement therapy, and provides some recommendations regarding use of them in peri- and postmenopausal women.

Gabapentin for Pruritus in Palliative care

Itch/pruritus can be very distressing in palliative care population and often is difficult to treat. Conventional antihistamines lack efficacy. Cutaneous and central pathogenesis of itch is extremely complex and unclear, making its treatment challenging. Neuronal mechanisms have been identified in the pathophysiology of itch hence providing a myriad of therapeutic options. It has been established that pruritus and pain neuronal pathway interact with each other, hence neuropathic analgesics like gabapentin has shown to be efficacious antipruritic therapeutic option. Gabapentin impedes transmitting nociceptive sensations to brain, thus also suppressing pruritus. Gabapentin is safe and found to be effective in uremic pruritus, cancer/hematologic causes, opiod-induced itch, brachioradial pruritis, burns pruritus, and pruritus of unknown origin. Further research is required in this area to establish whether gabapentin is consistently effective.

Androgen deprivation therapy-associated vasomotor symptoms

Androgen deprivation therapy (ADT) is widely used as standard therapy in the treatment of locally advanced and metastatic prostate cancer. While efficacious, ADT is associated with multiple side effects, including decreased libido, erectile dysfunction, diabetes, loss of muscle tone and altered body composition, osteoporosis, lipid changes, memory loss, gynecomastia and hot flashes. The breadth of literature for the treatment of hot flashes is much smaller in men than that in women. While hormonal therapy of hot flashes has been shown to be effective, multiple non-hormonal medications and treatment methods have also been developed. This article reviews current options for the treatment of hot flashes in patients taking ADT.

Non-estrogen conventional and phytochemical treatments for vasomotor symptoms: what needs to be known for practice

OBJECTIVE

Non-hormonal treatment for menopausal vasomotor symptoms (VMS) is needed in women in whom there are medical or personal concerns on the use of hormone therapy. This paper reviews conventional and phytochemical therapies available for the relief of VMS, on their mechanisms of action, their efficacy and safety concerns.

METHODS

Medline was searched through Pubmed on the names of the diverse therapies analyzed, up to June 2011. The Cochrane Controlled Clinical Trials Register Database was searched for relevant trials that provided data on treatment of menopausal hot flushes.

RESULTS

All non-estrogen treatments for VMS are less efficacious than estrogen treatment. Randomized trials with neuroendocrine agents show globally modest to moderate reduction of VMS and frequent bothersome adverse events. The variability of effects makes it possible to undergo treatment in search for individual response where estrogen treatment is contraindicated. The antidepressants that interact with cytochrome P450, inhibiting tamoxifen metabolism to endoxifen, interfere with tamoxifen therapy in breast cancer patients. Otherwise, botanical products containing isoflavones from soy bean or red clover have great variability in bioavailability, have a broader spectrum of action than estradiol, and have predominant estrogen receptor-b activity. The efficacy of phytoestrogens on VMS is similar to placebo. They should be avoided in women with breast cancer and, in particular, in women being treated with tamoxifen or aromatase inhibitors due to possible antagonism. Cimicifuga racemosa is not a phytoestrogen, has partial serotonin agonist action and has a modest effect on VMS.

CONCLUSIONS

There are safe non-hormonal conventional treatments for menopausal VMS, although they are less efficacious than estrogens. The indication of phytochemicals is for women who make this choice on personal beliefs; long-term studies of larger groups of patients are needed to assess safety.

Pilot evaluation of a stellate ganglion block for the treatment of hot flashes

PURPOSE

Hot flashes are a significant problem in breast cancer patients, especially because the most effective therapy, estrogen, is often contraindicated. Based on recent pilot data from a single group supporting the use of a stellate ganglion block for the treatment of hot flashes, the present pilot trial was done to further evaluate the hypothesis that a stellate ganglion block may be a safe and effective therapy for hot flashes.

METHODS

In women with breast cancer who had hot flashes, a stellate ganglion block was performed after 1 week of baseline hot flash data collection. The main efficacy measures were the changes from baseline in hot flash frequency and hot flash score during the 6th week.

RESULTS

Ten patients were enrolled between 4/23/2009 and 7/10/2009; eight patients were evaluable. After the stellate ganglion block, the mean hot flash frequency and score decreased from baseline values by over 60% during some of the post-treatment weeks. The mean hot flash frequency and score at week 6 decreased from baseline values by 44% and 45%, respectively. There were no significant adverse events clearly attributed to the stellate ganglion blocks.

CONCLUSIONS

The results of this pilot trial support that stellate ganglion blocks may be a helpful therapy for hot flashes. A prospective placebo-controlled clinical trial should be done to more definitively determine this contention.

Use of gabapentin for the management of natural or surgical menopausal hot flashes

OBJECTIVE

To review the literature examining the use of gabapentin for treatment of hot flashes during natural or surgically induced menopause.

DATA SOURCES

A literature search was conducted via PubMed, MEDLINE, and International Pharmaceutical Abstracts (1948-November 2010) using the search terms gabapentin, hot flashes, and menopause. Literature was limited to English-language, human studies. Additional material was identified by reviewing reference citations of the articles retrieved.

STUDY SELECTION AND DATA EXTRACTION

Studies with data describing gabapentin for hot flash management during natural or surgically induced menopause were included. Any studies including women with a history of breast cancer were excluded. Four studies met the inclusion criteria.

DATA SYNTHESIS

Gabapentin significantly decreased hot flash frequency and hot flash composite scores by 45-71% from baseline in the 4 trials included in this review. In 2 of the trials, gabapentin was comparable to hormone replacement therapy (71% vs 72%, respectively, p=0.63) in decreasing hot flash composite scores at the end of 12 weeks and in decreasing hot flash frequency at the end of 8 weeks (58.9% vs 70.1%, p>0.05). In all trials, the most common adverse effects with gabapentin were somnolence/drowsiness, unsteadiness, and dizziness. These adverse effects were most pronounced during the first 1-2 weeks of therapy, but resolved and were similar to those reported with placebo by week 4. These trials were short (<12 weeks) and had small sample sizes; however, their results appear to show that gabapentin is safe and effective for short-term treatment of hot flashes in women who have entered menopause either naturally or surgically.

CONCLUSIONS

Gabapentin 600-2400 mg/day in divided doses may be a viable option for treating hot flashes in menopausal women who do not want to use hormone replacement therapy.

Hot flushes: are there effective alternatives to estrogen?

Hot flushes are the most common indication for the prescription of hormone replacement therapy (HRT) since it is effective in over 80% of cases. In 1995, 37% of American women took HRT, principally for this purpose. However, over the last five years, publications such as those from the Women's Health Initiative (WHI) have caused concern among women since they perceive that the risks outweigh the benefits. Following this publication, half of the women taking HRT in the UK, USA and New Zealand discontinued HRT. With the discontinuation of estrogen many women re-developed hot flushes; however only a small number (18%) of women report restarting hormone therapy. The majority of these (76%) for the recurrence of severe hot flushes or night sweats. Alternatives are available, but limited knowledge on aetiology and mechanisms of hot flushing represents a major obstacle for the development of new, targeted, non-hormonal treatments, and no current alternatives are as effective as estrogen.

Management of menopause-associated vasomotor symptoms: Current treatment options, challenges and future directions

Hot flashes are one of the most common and distressing symptoms associated with menopause, occurring in more than 75% of postmenopausal women. They are especially problematic in breast cancer patients since some breast cancer therapies can induce hot flashes. For mild hot flashes, it is proposed that behavioral modifications are the first step in management. Hormonal therapies, including estrogens and progestogens, are the most well known effective agents in relieving hot flashes; however, the safety of these agents is controversial. There is an increasing amount of literature on nonhormonal agents for the treatment of hot flashes. The most promising data regard newer antidepressant agents such as venlafaxine, which reduces hot flashes by about 60%. Gabapentin is another nonhormonal agent that is effective in reducing hot flashes. While many complimentary therapies, including phytoestrogens, black cohosh, and dehydroepiandrosterone, have been explored for the treatment of hot flashes; none can be recommended at this time. Furthermore, there is a lack of strong evidence to support exercise, yoga, or relaxation for the treatment of hot flashes. Paced respirations and hypnosis appear to be promising enough to warrant further investigation. Another promising nonpharmacological therapy, currently under investigation, involves a stellate ganglion block.

Phase III, randomized, double-blind, placebo-controlled evaluation of pregabalin for alleviating hot flashes, N07C1

PURPOSE

Hot flashes are a common problem for which effective and safe treatments are needed. The current trial was conducted on the basis of preliminary promising data that pregabalin decreased hot flashes.

PATIENTS AND METHODS

A double-blind, placebo-controlled, randomized trial design was used to compare pregabalin at target doses of 75 mg twice daily and 150 mg twice daily with a placebo. Hot flash frequencies and scores (frequency times mean severity) were recorded daily during a baseline week and for six treatment weeks. The primary end point for this study was the change-from-baseline hot flash score during treatment week 6 between the 150 mg twice daily target pregabalin treatment and placebo. Nonparametric Wilcoxon rank sum tests, two-sample t tests, and chi(2) tests were used to compare the primary and secondary hot flash efficacy end points between pregabalin treatments and placebo.

RESULTS

Hot flash score changes available for 163 patients during the sixth treatment week compared with a baseline week decreased by 50%, 65%, and 71% in the placebo, and target 75 mg twice daily and 150 mg twice daily pregabalin arms, respectively (P = .009 and P = .007, comparing respective pregabalin arms to the placebo arm). While some toxicities were significantly more common in the pregabalin arms, being more evident with the higher dose, pregabalin was generally well tolerated by most patients.

CONCLUSION

Pregabalin decreases hot flashes and is reasonably well tolerated. A target dose of 75 mg twice daily is recommended. Its effects appear to be roughly comparable to what has been reported with gabapentin and with some newer antidepressants.

Therapy: nonhormonal treatment of hot flashes-a viable alternative?

A new study published in the Journal of Clinical Oncology has ascertained the efficacy of selective serotonin-reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors and gabapentin to decrease menopausal hot flashes. Are these nonhormonal treatment options a viable alternative to hormone replacement therapy?

Non-estrogenic approaches for the treatment of climacteric symptoms

Non-estrogenic alternatives for the treatment of climacteric symptoms have their origin lost in history. Recent clinical trial data have shown that lifestyle and diet adjustment have some effect in improving both hot flushes and mood. Over-the-counter phytotherapeutic extracts are very popular and women often try a variety of products before resorting to traditional medicine. Preparations containing isoflavones in variable doses, such as soy extract and red clover, or extracts from evening primrose, Cimifuga racemosa, ginseng and black cohosh are often used for treating the climacteric syndrome. The scientific support for their efficacy certainly does not equal their popularity. The most tested pharmacological alternatives to estrogens are serotonin reuptake inhibitors (SSRIs). All available SSRIs have undergone trials for the relief of hot flushes. In spite of the difference between the compounds in both half-life and engagement of serotonin receptors, they appear to have very similar effectiveness in reducing hot flushes. At their best, SSRIs reduce hot flushes by 50-60%, compared with 80% for estrogen, and their effect appears only in the short term. SSRIs have mood-improving effects that appear to be independent of the effect on hot flushes. When used for the treatment of the climacteric syndrome, SSRIs do not adversely affect libido. Dependence is a major concern in women when offered this type of treatment, but does not appear to be a problem with this class of drugs. Withdrawal symptoms have never been reported in trials for hot flushes but are known to occur when SSRIs are used in the long term. In order to avoid these symptoms, the dose should be tapered slowly. Gabapentin, a drug used for the treatment of neuropathic pain and epilepsy, has shown that, in high doses, it has an efficacy similar to that of estrogen; however, this needs further confirmation.

Newer antidepressants and gabapentin for hot flashes: an individual patient pooled analysis

PURPOSE

Nonhormonal treatment options have been investigated as treatments for hot flashes, a major clinical problem in many women. Starting in 2000, a series of 10 individual double-blind placebo-controlled studies has evaluated newer antidepressants and gabapentin for treating hot flashes. This current project was developed to conduct an individual patient pooled analysis of the data from these published clinical trials.

PATIENTS AND METHODS

Individual patient data were collected from the various study investigators who published their study results between 2000 and 2007. Between-study heterogeneity for study characteristics and patient populations was tested via chi2 tests before a pooled analysis. The primary end point, the change in hot flash activity from baseline to week 4, for each agent was calculated via both weighted and unweighted approaches, using the size of the study as the weight. Basic summary statistics were produced for hot flash score and frequency using the following three statistics: raw change, percent reduction, and whether or not a 50% reduction was achieved.

RESULTS

This study included seven trials of newer antidepressants and three trials of gabapentin. The optimal doses (defined by individual study results) of the newer antidepressants paroxetine, venlafaxine, fluoxetine, and sertraline decreased hot flash scores by 41%, 33%, 13%, and 3% to 18% compared with the corresponding placebo arms, respectively. The three gabapentin trials decreased hot flashes by 35% to 38% compared with the corresponding placebo arms.

CONCLUSION

Some newer antidepressants and gabapentin, within 4 weeks of therapy initiation, decrease hot flashes more than placebo.

Current alternative and complementary therapies used in menopause

OBJECTIVE

To determine the efficacy and safety of common complementary and alternative medicine (CAM) therapies used to relieve the menopausal symptoms.

DESIGN

Comprehensive literature search was conducted through the databases Medline, EMBASE, Cochrane, AMED (Allied and Complementary Medicine), NCCAM (The National Centre for Complementary and Alternative Medicine) to identify relevant monographs in English language.

RESULTS

Studies have shown that some therapies such as clonidine, selective serotonin receptor inhibitors (SSRIs) and gabapentin are effective in decreasing the degree and frequency of somatic symptoms in menopause, while phytooestrogens and black cohosh have shown mixed results. Use of Ginseng, evening primrose, Dong Quai or vitamin E appears not to be efficacious for the relieving hot flushes. Other effects of these therapies including possible improvements in mood are yet to be substantiated.

INCLUSION CRITERIA

All available human complementary medicine studies on menopausal women with regard to the relief of menopausal symptoms.

EXCLUSION CRITERIA

Studies not meeting the inclusion criteria, published in languages other than English or animal studies.

CONCLUSION

There is a general lacking of longer-term follow-up beyond the trial lengths of 6-12 weeks in the use of CAM, although women may be taking these medications for many years. Well-designed, randomised control trials are needed to elucidate the true effect of these therapies above the placebo effect.

A phase III randomized, double-blind, placebo-controlled trial of gabapentin in the management of hot flashes in men (N00CB)

INTRODUCTION

Hot flashes represent a significant problem in men undergoing androgen deprivation therapy.

MATERIALS AND METHODS

Via a prospective, double-blind, placebo-controlled clinical trial, men with hot flashes, on a stable androgen deprivation therapy program for prostate cancer, received a placebo or gabapentin at target doses of 300, 600, or 900 mg/day. Hot flash frequencies and severities were recorded daily during a baseline week and for 4 weeks while the patients took the study medication.

RESULTS

In the 214 eligible patients who began the study drug on this trial, comparing the fourth treatment week to the baseline week, mean hot flash scores decreased in the placebo group by 4.1 units and in the three increasing dose gabapentin groups by, 3.2, 4.6, and 7.0 units. Comparing the three combined gabapentin arms to the placebo arm did not result in significant hot flash differences. Wilcoxon rank-sum P values for change in hot flash scores and frequencies after 4 weeks of treatment were 0.10 and 0.02, comparing the highest dose gabapentin arm to the placebo arm, respectively. The gabapentin was well tolerated in this trial.

CONCLUSION

These results support that gabapentin decreases hot flashes, to a moderate degree, in men with androgen ablation-related vasomotor dysfunction.

Symptom management in premenopausal patients with breast cancer

Women with breast cancer have many adverse symptoms, of which some are specific to premenopausal patients. Management of these common symptoms include non-hormonal drugs, such as antidepressants and antiseizure compounds to alleviate hot flushes. Non-oestrogenic vaginal lubricants seem to moderately decrease occurrence of vaginal dryness and dyspareunia. Transdermal testosterone alone has not been shown to improve libido in these women. Options for fertility preservation include cryopreservation of embryos or oocytes before chemotherapy. Exercise is the one evidenced-based intervention shown to positively affect cancer-related fatigue. However, effective prevention and treatments for peripheral neuropathy and paclitaxel acute pain syndrome remain elusive. Weight-bearing exercise helps to maintain bone strength with adequate intake of calcium and vitamin D. Use of bisphosphonates in women taking aromatase inhibitors (combined with ovarian suppression in premenopausal women) to prevent bone fractures has not been substantiated, although it should be considered in women with osteoporosis. No specific drug has been shown to prevent radiation-induced dermatitis alone. Although some effective treatments can counteract symptoms related to cancer or treatments, research is needed to expand evidence-based care in premenopausal survivors of breast cancer.

Gabapentin for the treatment of menopausal hot flashes: a randomized controlled trial

OBJECTIVE

To compare the effectiveness and tolerability of gabapentin with placebo for the treatment of hot flashes in women who enter menopause naturally.

DESIGN

A randomized, double-blind, placebo-controlled trial was conducted across the greater Toronto area between March 2004 and April 2006 in the community and primary care settings. Eligible participants were 200 women in natural menopause, aged 45 to 65 years, having at least 14 hot flashes per week. Study participants were randomized to receive gabapentin 300 mg oral capsules or placebo three times daily for 4 weeks. The primary outcome measure was the mean percentage change from baseline to week 4 in daily hot flash score, determined from participant diaries. Secondary outcome measures included changes in weekly mean hot flash scores and frequencies, quality of life, and adverse events.

RESULTS

Of the 197 participants, 193 (98%) completed the study. Analysis was by intention to treat. Hot flash scores decreased by 51% (95% CI: 43%-58%) in the gabapentin group, compared with 26% (95% CI: 18%-35%) on placebo, from baseline to week 4. This twofold improvement was statistically significant (P < 0.001). The Menopause-Specific Quality-of-Life vasomotor score decreased by 1.7 (95% CI: 1.3-2.1; P < 0.001) in the gabapentin group. These women reported greater dizziness (18%), unsteadiness (14%), and drowsiness (12%) at week 1 compared with those taking placebo; however, these symptoms improved by week 2 and returned to baseline levels by week 4.

CONCLUSIONS

Gabapentin at 900 mg/day is an effective and well-tolerated treatment for hot flashes.

Non-hormonal therapy of post-menopausal vasomotor symptoms: a structured evidence-based review

BACKGROUND

Interest in non-hormonal therapies for the treatment of menopausal symptoms has increased since the publication of adverse effects of estrogen replacement therapy.

OBJECTIVE

To provide information on the efficacy of non-hormonal therapies for menopausal vasomotor symptoms based on evidence from published randomised controlled studies.

METHODS

The Cochrane Database of Systematic Reviews (CDSR), MEDLINE, Alternative Therapies in Health and Medicine database (ATHMD) and Allied and Complementary Medicine database (AMED) were searched for randomised controlled trials in the English language reporting data on treatment of menopausal vasomotor symptoms. Trials including cancer breast patients were included.

RESULTS

Our search identified 58 randomised controlled trials of which 11 involved the use of clonidine, six for SSRIs, four for gabapentin, seven for black cohosh, seven for red clover, 18 for phytoestrogens, two for ginseng, one for evening primrose, one for dong quai and one for vitamin E. Most trials had methodological deficiencies.

CONCLUSION

There is evidence that clonidine, paroxetine, venlafaxine, gabapentin and black cohosh may be beneficial in the treatment of menopausal vasomotor symptoms in some women. Current evidence does not support the use of fluoxetine, red clover, phytoestrogens, Ginseng, evening primrose, dong quai and vitamin E. The side effects profile of these therapies should be considered.

Minimal decrease in hot flashes desired by postmenopausal women in family practice

OBJECTIVE

To determine the minimal important difference in the frequency and severity of hot flashes that postmenopausal women desire from a nonhormonal agent.

DESIGN

Women recorded their number of hot flashes daily, along with their degree of severity, using a diary for 1 week and completed the Menopause-Specific Quality of Life Questionnaire. Women were asked to report the percentage reduction in hot flashes that they would find clinically important. Distribution-based estimates were used to estimate the minimal important difference.

RESULTS

Approximately 69% of the postmenopausal women who reported their hot flashes as moderate to severe responded that they wanted a nonhormonal agent that provided at least a 50% mean reduction in the frequency of hot flashes (95% CI, 32% to 66%). Median hot flash reduction for all respondents was 50%.

CONCLUSIONS

The minimal clinically important difference in hot flashes is approximately 50%. This estimate can provide the basis to calculate sample size in clinical trials of anti-hot flash agents and in selecting possible candidates for investigation.

Androgen deprivation therapy: monitoring and managing the complications

Because many patients who have biochemical relapse will live for many years,preventing additional morbidity in those who are treated with ADT is of the utmost importance. No standard therapy is currently available for men who have biochemical relapse, although data are beginning to show that earlierADT may result in improved survival, at least in patients who have somewhat more advanced disease or rapid PSA doubling times or velocities. Treatment with intermittent ADT may attenuate some of the morbidities, such as loss of bone mineral density. Not all patients will experience all or even many of these complications, but patients can be empowered by learning about these beforehand and under-standing what can be done to prevent, monitor, or treat the side effects. Table 2 summarizes recommendations for baseline evaluations of men prior to initiation of ADT, and Table 3 summarizes interventions for specific complications. Better markers to distinguish patients who will benefit from ADT are needed. Newer hormonal agents or supplements are being researched. In the meantime, patients and the health care team can work together to combat complications related to ADT.

Hot flash therapies in breast cancer survivors

More than 86% of those diagnosed with invasive breast cancer are expected to survive for >/= 5 years after their diagnosis. Approximately 75% of postmenopausal women who had breast cancer report experiencing hot flashes. More than 90% of young survivors also experience hot flashes, which can be more severe and long lasting, with iatrogenic ovarian ablation or antiestrogen therapy. There are numerous options for the treatment of hot flashes. Not one treatment fits all. Some treatments are generally more effective than others, and each has different side effects. This review is meant to provide the basic information needed to make a decision about the best treatment for a breast survivor experiencing hot flashes.

Gabapentin, Estrogen, and Placebo for Treating Hot Flushes

OBJECTIVE

To compare the efficacy of gabapentin, estrogen, and placebo in the treatment of hot flushes.

METHODS

We performed a randomized, double-blind, placebo-controlled trial of 60 postmenopausal women to assess the efficacy of estrogen and gabapentin in the treatment of moderate-to-severe hot flushes. Participants were randomly assigned to receive either 0.625 mg/d of conjugated estrogens (n = 20), placebo (n = 20), or gabapentin titrated to 2,400 mg/d (n = 20) for 12 weeks. Participants recorded frequency and severity of baseline hot flushes on a hot flush diary for 2 weeks before randomization and for 12 weeks after randomization. The primary outcome measure was the weekly hot flush composite score, which takes into account both severity and frequency of hot flushes. Secondary outcome measures were differences in pre- and posttreatment scores pertaining to depression (Zung Depression Scale) and other climacteric symptoms (Greene Climacteric Scale).

RESULTS

Intention-to-treat analysis showed that the reduction in the hot flush composite score for both estrogen (72%, P = .016) and gabapentin (71%, P = .004) was greater than the reduction associated with placebo (54%) at the conclusion of the 12th week. The extent of reduction in hot flush composite score, however, was not significantly different between estrogen and gabapentin (P = .63). No differences were seen between groups in the Zung Depression Scale, or in any of the Greene Climacteric subscales except for the Somatic Symptom cluster, which was significantly greater in the gabapentin arm than in the placebo arm. Despite a lack of group differences in adverse events, the Headache, Dizziness, and Disorientation cluster appeared with greater frequency in the gabapentin group. Estimation of the number needed to harm in this cluster suggests that these symptoms may occur with every fourth patient treated with gabapentin.

CONCLUSION

Despite the small scale of this study, gabapentin appears to be as effective as estrogen in the treatment of postmenopausal hot flushes.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov, NCT 00276081.

LEVEL OF EVIDENCE

I.

Treatment of hot flushes in breast and prostate cancer

Hot flushes, the most common health problem reported by menopausal-age women, can lead to significant morbidity and affect the social life, ability to work and sleep pattern of the sufferer. Women treated for breast cancer and men receiving androgen ablation for prostate cancer experience hot flushes that are more frequent, severe and longer lasting than those experienced by the general menopausal population. In women with breast cancer, hot flushes can result from chemotherapy-induced menopause, hormonal therapy, or ovarian suppression. In men with prostate cancer, hot flushes occur after surgical or medical castration. Hormone replacement therapy with oestrogen-based compounds has been a mainstay of treatment for hot flushes during the perimenopausal period. However, recent studies have shown that, in healthy menopausal women, hormone replacement therapy is associated with an increased risk of breast cancer, myocardial infarction, thrombo-embolic events and stroke. Thus, identifying nonhormonal agents that can control hot-flush symptoms is essential to the quality of life of a growing population of cancer survivors. The most promising agents act on the CNS and include selective serotonin reuptake inhibitors, as well as venlafaxine and gabapentin.

A Review of Non-Hormonal Options for the Relief of Menopausal Symptoms

The climacteric syndrome involves a variety of symptoms such as profuse sweating, insomnia, memory loss, decreased sexual drives, joint aches, and anxiety. However, amongst these symptoms, hot flashes and sweats are generally considered the hallmark and result in the majority of the medical consultations for this condition. Hot flashes are known to respond readily to placebo, which alone decreases their frequency by 20-40%. In the ideal setting of clinical trials, with optimal patient selection and compliance, estrogen therapy reduces hot flashes by about 70-80%; this is twice as effective as placebo. However, estrogen is unable to be universally used, either because of contraindications or because of an unwillingness of women to take it. Furthermore, hot flashes may persist in spite of adequate estrogen replacement, and physicians are often faced with the dilemma of finding something to administer in place of, or in addition to, estrogen to improve symptoms. The most commonly used non-hormonal alternatives for climacteric symptoms are neurotransmitter modulators such as serotonin reuptake inhibitors and gabapentin. These are, at best, approximately half as effective as estrogen for the relief of menopausal symptoms, and are only marginally better than placebo.Complementary treatment, particularly over-the-counter phytotherapeutic extracts, are very popular and women often try a variety of such products before resorting to conventional medicine. Preparations containing isoflavones, such as soy extract and red clover or extracts from evening primrose or cimicifuga (black cohosh, Actaea racemosa, syn. Cimicifuga racemosa), in variable doses are very popular for the treatment of hot flashes. The scientific support for their efficacy certainly does not equal their popularity.Non-hormonal treatments for menopause are not as effective as estrogens in relieving hot flashes, but may have a role in therapy for women who have contraindications to gonadal steroid use.

Centrally active nonhormonal hot flash therapies

Given the problems associated with hormonal therapy, and the prominent problem of hot flashes in menopausal women, there is a need for nonhormonal agents to alleviate hot flashes. Several compounds that appear to act on the central nervous system have been investigated. Potential mechanisms for their effects on hot flashes have been described. Bellergal (no longer available on the US market, where it was known as Bellergal-S), a combination preparation sedative that consists of low-dose phenobarbital, ergotamine tartrate, and levorotatory alkaloids of belladonna, is an old agent that was popular approximately 20 years ago; however, there is limited suggestion of efficacy for this agent. Clonidine, an older antihypertensive drug, is another centrally active agent that has been studied. Randomized trials have demonstrated that it clearly works for reducing hot flashes, but the magnitude of efficacy is somewhat limited. Toxicity from this agent limits its utility in the clinic. Methyldopa is another centrally active agent that has been studied but to a more limited degree. It appears to have minimal efficacy and too much toxicity to make it clinically useful. Anecdotal observations from a number of sources suggested that newer antidepressants can alleviate hot flashes. This led to pilot trials of venlafaxine and paroxetine, with results suggesting benefit from both drugs. Subsequently, randomized, placebo-controlled, double-blind clinical trials of venlafaxine, paroxetine, and fluoxetine were conducted. All 3 of these clinical trials demonstrated statistically significant reductions in hot flashes with these newer antidepressants compared with placebo. Pilot trials of citalopram and mirtazapine, 2 other newer antidepressants, have also suggested efficacy. Toxicity evaluations have suggested that these agents are, again, well tolerated by the majority of patients. A recent trial, however, was unable to demonstrate any benefit for fluoxetine or citalopram over a placebo. Anecdotal observations also suggested that gabapentin was helpful for alleviating hot flashes. This led to pilot trials that again suggested efficacy. Subsequently, 2 large placebo-controlled, randomized, double-blind clinical trials were conducted. Both of these demonstrated statistically significant efficacy for gabapentin compared with a placebo. This drug is relatively well tolerated by most patients. Thus, centrally active nonhormonal agents clearly do decrease hot flashes in women. The most efficacious and clinically appropriate agents for use are newer antidepressants and gabapentin. Continued evaluation of the efficacy and toxicity of these agents is ongoing.

Parenteral medroxyprogesterone for the management of luteinizing hormone releasing hormone induced hot flashes in men with advanced prostate cancer

PURPOSE

Luteinizing hormone releasing hormone (LHRH) agonist therapy for advanced prostate cancer can manifest significant side effects affecting quality of life, most notably hot flashes. This study evaluated the effectiveness of parenteral medroxyprogesterone acetate (MPA) in reducing the frequency and severity of these hot flashes.

MATERIALS AND METHODS

A multi-institutional retrospective review of hot flashes from LHRH therapy for prostate cancer was conducted. The hot flashes were quantified and the severity was graded (3-point analogue scale) before and after treatment with MPA. Two doses of MPA (400 or 150 mg intramuscularly) were administered. Statistical analysis (Student's t test) evaluated the quantity of hot flashes, the quality of hot flashes, and dose effectiveness.

RESULTS

A total of 48 men (40 at 400 mg, 8 at 150 mg) with a mean age of 71.4 years (range 54 to 87) from 3 institutions were evaluated. There were 91% with symptomatic improvement with MPA, and half (46%) had a complete response defined as total elimination of hot flashes. The median number of the hot flashes per day decreased from 4 to 1 and the median severity score decreased from 2 to 1 (p <0.05). Significance was not achieved comparing the 2 doses. Complete responders were not noted with the 150 mg dose. Anticipated response to MPA did not correlate with the number or severity of the hot flashes.

CONCLUSIONS

This study is the first multi-institutional evaluation of hot flashes demonstrating significant reduction in quantity and severity with MPA. Based on these data we now manage hot flashes associated with LHRH analogues with 400 mg of MPA.

Gabapentin for hot flashes in 420 women with breast cancer: a randomised double-blind placebo-controlled trial

BACKGROUND

Most women receiving systemic therapy for breast cancer experience hot flashes. We undertook a randomised, double-blind, placebo-controlled, multi-institutional trial to assess the efficacy of gabapentin in controlling hot flashes in women with breast cancer.

METHODS

420 women with breast cancer who were having two or more hot flashes per day were randomly assigned placebo, gabapentin 300 mg/day, or gabapentin 900 mg/day by mouth in three divided doses for 8 weeks. Each patient kept a 1-week, self-report diary on the frequency, severity, and duration of hot flashes before the start of the study and during weeks 4 and 8 of treatment. Analyses were by intention to treat.

FINDINGS

Evaluable data were available on 371 participants at 4 weeks (119 placebo, 123 gabapentin 300 mg, and 129 gabapentin 900 mg) and 347 at 8 weeks (113 placebo, 114 gabapentin 300 mg, and 120 gabapentin 900 mg). The percentage decreases in hot-flash severity score between baseline and weeks 4 and 8, respectively were: 21% (95% CI 12 to 30) and 15% (1 to 29) in the placebo group; 33% (23 to 43) and 31% (16 to 46) in the group assigned gabapentin 300 mg; and 49% (42 to 56) and 46% (34 to 58) in the group assigned gabapentin 900 mg. The differences between the groups were significant (p=0.0001 at 4 weeks and p=0.007 at 8 weeks by ANCOVA for overall treatment effect, adjusted for baseline values); only the higher dose of gabapentin was associated with significant decreases in hot-flash frequency and severity.

INTERPRETATION

Gabapentin is effective in the control of hot flashes at a dose of 900 mg/day, but not at a dose of 300 mg/day. This drug should be considered for treatment of hot flashes in women with breast cancer.

State of the science: hot flashes and cancer. Part 2: management and future directions

PURPOSE/OBJECTIVES

To critically evaluate and synthesize intervention research related to hot flashes in the context of cancer and to identify implications and future directions for policy, research, and practice.

DATA SOURCES

Published, peer-reviewed articles and textbooks; editorials; and computerized databases.

DATA SYNTHESIS

Although a variety of pharmacologic and nonpharmacologic treatments are available, they may not be appropriate or effective for all individuals.

CONCLUSIONS

The large and diverse evidence base and current national attention on hot flash treatment highlight the importance of the symptom to healthcare professionals, including oncology nurses.

IMPLICATIONS FOR NURSING

Using existing research to understand, assess, and manage hot flashes in the context of cancer can prevent patient discomfort and improve the delivery of evidence-based care.

Effect of calcium channel modulators on temperature regulation in ovariectomized rats

Clinical studies evaluating a calcium channel modulator, gabapentin, for the treatment of vasomotor symptoms have been reported. The present studies evaluated three calcium channel modulators in ovariectomized (OVX) rodent models of temperature regulation. Gabapentin, reported to interact with the alpha(2)delta subunit of voltage-sensitive calcium channels and the L-type voltage-gated calcium channel blockers, verapamil and nifedipine, were examined. These series of experiments demonstrated that orally administered gabapentin, verapamil and nifedipine all acutely and dose-dependently lower tail skin temperature in both models of OVX-induced thermoregulatory dysfunction. These compounds all had a rapid onset of action, however, the efficacy of all three calcium channel modulators is less than that observed following chronic estrogen treatment. Additionally, these compounds were also tested in a telemetric rat model measuring core body temperature to evaluate any temperature effects on internal core temperature. The present data suggests that gabapentin, verapamil and nifedipine all act to globally alter temperature regulation in steroid-dependent models of thermoregulatory function.

Therapy for Menopausal Symptoms During and After Treatment for Breast Cancer

Breast cancer is the most common newly diagnosed cancer in women. Life-time risk in the US is 1 in 8 (13.2%), in the UK it is 1 in 9 and in Australia it affects 1 in 11 women, of whom approximately 27% will be premenopausal at the time of their diagnosis. Many of these women will experience a sudden menopause as a result of chemotherapy, endocrine therapy or surgical interventions. For these women, the onset of menopausal symptoms is often sudden and severe. The management of such symptoms remains controversial. Women experiencing menopausal symptoms after breast cancer should be encouraged to avoid identifiable triggers for their symptoms and to consider lifestyle modification as a means of controlling those symptoms. When such measures fail, non-hormonal treatments may also be considered. These include clonidine, gabapentin and some antidepressants. Randomised trials have shown a significant difference in the symptom relief associated with various selective serotonin reuptake inhibitors and selective serotonin and noradrenaline (norepinephrine) reuptake inhibitors compared with placebo. Many women elect to use non-prescription complementary therapies to alleviate their menopausal symptoms. Systematic reviews of phytoestrogens have, however, failed to demonstrate significant relief of menopausal symptoms. More than 20 clinical trials have been conducted examining the relationship between postmenopausal hormone replacement therapy and breast cancer recurrence. The majority of these have been observational and have shown no increased risk of recurrence. However, the largest randomised trial that has thus far been conducted was recently halted because of a reported increase in the risk of recurrence amongst users of hormone replacement therapy. Tibolone, a selective tissue estrogen activity regulator, is a compound that exerts clinical effects both by receptor-mediated actions and tissue selective enzyme inhibition, and has been shown in preclinical studies to have different effects to estrogen on the breast. Although tibolone may prove safer than estrogen for long-term use in breast cancer survivors, the results of a large randomised trial are awaited to confirm this.The decision on how best to manage menopausal symptoms must thus be made on an individual basis and after thorough discussion and evaluation of the risks and benefits of each potential intervention.

Alternatives to estrogen to manage hot flushes

Hot flushes are probably the most common symptom resulting in medical consultation in relation to the menopause and, when severe, they can affect quite dramatically women's quality of life. Hormone (estrogen) replacement therapy (HRT) is the most effective treatment for this symptom and in the ideal setting of clinical trials, under optimal selection of patients and compliance, it reduces hot flushes by about 70-80%. Recently, however, a series of 'scares' has had large resonance in the lay press about possible adverse effects of HRT. These have undermined both doctors' and women's confidence in the use of these compounds. This has been witnessed by the recent fall in HRT sales. A number of compounds, both pharmacological and herbal in origin, have been used for the treatment of neurovegetative symptoms in menopausal women. The present article critically reviews evidence of the efficacy of some of the most commonly used compounds and assesses their effect in relation to that of HRT.

Nonestrogen Treatment Modalities for Vasomotor Symptoms Associated with Menopause

OBJECTIVE:

To systematically review the literature regarding the efficacy and safety of nonestrogen treatments for menopause-associated vasomotor symptoms not due to cancer or chemotherapy.

DATA SOURCES:

Pertinent literature and clinical studies were identified by searching MEDLINE (1966–February 2004) and EMBASE (1959–February 2004) using the key search terms vasomotor symptoms, hot flashes, and menopause. Bibliographies of relevant articles were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION:

English-language articles reporting efficacy and safety of nonestrogen treatment modalities for perimenopausal and postmenopausal vasomotor symptoms were evaluated. All articles identified from the data sources were evaluated, and all information deemed relevant was included. Emphasis was placed on randomized, double-blind, placebo-controlled clinical trials, as these provide the best efficacy and safety data. Studies evaluating treatment of vasomotor symptoms from other causes, such as cancer or chemotherapy, were excluded.

DATA SYNTHESIS:

Prescription medications reviewed for efficacy and safety in postmenopausal vasomotor symptoms include clonidine hydrochloride, danazol, gabapentin, methyldopa, mirtazapine, progestins, propranolol hydrochloride, selective serotonin-reuptake inhibitors (SSRIs), and venlafaxine. Nonprescription therapies reviewed include black cohosh, dong quai, evening primrose oil, physical activity, phytoestrogens, and red clover.

CONCLUSIONS:

According to this systematic literature review, postmenopausal vasomotor treatments that have been shown to be safe and effective in short-term use include black cohosh, exercise, gabapentin, medroxyprogesterone acetate, SSRIs (ie, paroxetine hydrochloride), and soy protein. Initial, small reports are suggestive for efficacy in menopausal vasomotor symptoms with megestrol acetate and venlafaxine.

Nonhormonal alternatives for the treatment of hot flashes

OBJECTIVE

To review the literature on clonidine, venlafaxine, selective serotonin reuptake inhibitors, and gabapentin for the treatment of hot flashes.

DATA SOURCES

A MEDLINE search (January 1966-July 2003) was conducted to identify English-language literature available on the treatment of hot flashes that focused on clonidine, venlafaxine, selective serotonin reuptake inhibitors, and gabapentin. These articles, relevant abstracts, and additional references listed in articles were used to collect pertinent data.

STUDY SELECTION

All controlled and uncontrolled trials were reviewed.

DATA SYNTHESIS

In women unable or unwilling to take hormonal therapies, several nonhormonal alternatives have been evaluated in small controlled and uncontrolled trials. Oral and transdermal formulations of clonidine are moderately effective in reducing hot flashes. Results of studies evaluating venlafaxine, paroxetine, and gabapentin suggest greater reductions in hot-flash frequency and severity compared with those of clonidine. Fluoxetine appears to display a modest benefit compared with paroxetine, although no comparative trials have been conducted. Most women studied in these trials had a history of breast cancer, and many were taking concurrent tamoxifen. All of these agents were fairly well tolerated.

CONCLUSIONS

Clonidine, venlafaxine, paroxetine, fluoxetine, and gabapentin are nonhormonal agents that have demonstrated efficacy in small controlled and uncontrolled trials in reducing hot flashes and should be considered in patients unwilling or unable to take hormonal therapies.