oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Hot flushes are due to vasomotor instability and are usually related to the female climacteric.
The aetiology of hot flushes would seem to be related to very high levels of gonadotrophins as the ovaries fail but there is still much that is not understood about their aetiology.
They do not tend to occur in men, as there is not a similar rapid decline in hormones. When hormone levels do fall in elderly men it is not accompanied by a surge in gonadotrophins. However, treatment for prostate cancer that involves suppression of testosterone production can produce a picture similar to menopausal hot flushes in women and can be just as severe.
Reported prevalence varies greatly between studies:
- Most studies agree that hot flushes and night sweats substantially increase in frequency and severity during the menopausal transition.
- These symptoms are experienced by more than 50% of menopausal women.
- Although most symptoms resolve within a few months, for many women, they can persist for several years after the final menstrual period. About 29% of 60-year-old women report persistent hot flushes.
- They tend to be more severe in women of low bodyweight, those who take little or no exercise and those who smoke cigarettes.
- They seem to be more common in black women and less common in Chinese women.
- An abrupt or early menopause causes more severe symptoms. Thus, surgical oophorectomy or its equivalent induced with chemotherapy, radiation or drugs produces more pronounced symptoms than a natural menopause.
- Hot flushes may last between a few seconds and 10 minutes but an average is around 4 minutes. Frequency may be from every hour to a couple of times a week.
- There is a sensation of intense heat and a feeling that the face and whole body is flushing. It is often difficult to ignore and women having hot flushes often fling open windows when all around them are anything but warm. Flushing and sweating may not be apparent to the observer but the sufferer tends to be very self-conscious of the affliction.
- Lack of concentration and poor memory are commonly associated.
- Sleep disturbance is common with night sweats. Features of depression are not unusual.
- Frequent flushes and disturbance of sleep may well be a major contributor to the commonly observed adverse effect on mood. There is evidence that the sex hormones do have an effect on mood and wellbeing in both men and women. Hormone replacement therapy (HRT) improves fatigue, depression, headaches and libido in men as well as women.
- Inappropriate vasodilatation leads to a slight drop in core temperature. Between attacks there is no abnormality to be found.
Other causes of flushing to consider:
- Carcinoid tumours.
- Medullary carcinoma of the thyroid.
- Carcinoma of the pancreas.
- Phaeochromocytoma (may be part of a multiple endocrine neoplasia syndrome).
- Brain tumours and spinal cord lesions (can lead to vasomotor instability).
- Frey's syndrome (flushing when the affected person eats, sees, thinks about or talks about certain kinds of food which produce strong salivation; may occur as a complication of parotid gland surgery).
- Some food substances, eg monosodium glutamate.
- Some drugs - for example, nitrates, nicotinic acid and calcium-channel blockers, anti-oestrogens (including tamoxifen), selective (o)estrogen receptor modulators (SERMS) - eg raloxifene, anti-androgens (eg cyproterone), danazol and goserelin (tolbutamide and chlorpropramide are the best known, but rarely prescribed nowadays).
- There may be a history of menstruation becoming irregular or ceasing but not necessarily. There may have been surgery, radiotherapy or chemotherapy, involving removal or inactivation of the ovaries. Similar causes of sudden withdrawal of sex hormones in men produce a similar response.
- If there is doubt about the diagnosis then oestrogen levels (or testosterone in men) will be low and follicle-stimulating hormone (FSH) and luteinising hormone (LH) will be raised (it may be necessary to obtain more than one blood sample to confirm the elevated gonadotrophins).
Hot flushes do not threaten life but they can have a marked effect on the quality of life. They will subside with time but a sympathetic and positive approach is required.
The following advice should be given:
- Take regular exercise, wear lighter weight clothing, sleep in a cooler room, and reduce stress. NB: diet and exercise have shown very little effect in some studies.
- Avoid possible triggers, such as spicy foods, caffeine, smoking, and alcohol.
HRT is the most effective form of treatment but concern over long-term safety has reduced its popularity with both doctors and patients. HRT has to be tailed off to prevent recurrence of the problem. The necessary duration of treatment is very variable but may be months or years. See separate Hormone Replacement Therapy article for details.
Alternative treatments to HRT include:
- Selective serotonin reuptake inhibitor antidepressants, which seem to be effective - for example, paroxetine (20 mg daily), fluoxetine (20 mg daily), citalopram (20 mg daily), or venlafaxine 37.5 mg twice a day (unlicensed).
- Clonidine 50-75 micrograms twice a day (licensed use) probably does work but side-effects can be a problem.
- A progestogen, eg norethisterone or megestrol (both unlicensed).
- The anticonvulsant gabapentin is also effective.
- Phyto-oestrogens, usually derived from soya or red clover, are at best just moderately effective.
- Many other herbal remedies have been used but vigorous trials tend to show little or no benefit.
- Vitamin E at 800 IU daily is quite popular but the proven benefit is not great.
- As a non-hormonal treatment, betablockers were once popular but have been shown to be ineffective.
- There is little evidence to support the use of acupuncture.
Trials of treatment for hot flushes may have to be interpreted with caution, as the placebo response can be as high as 20-30%. Almost all trials are on women, as symptoms are much more common in women than men. Where both men and women have been included in trials, the results seem similar and so extrapolation appears valid.
Despite the very high placebo response the benefits of behavioural modification are very limited and most trials have small numbers.
Further reading & references
- Stearns V, Ullmer L, Lopez JF, et al; Hot flushes. Lancet. 2002 Dec 7;360(9348):1851-61.
- No authors listed; Herbal medicines for menopausal symptoms. Drug Ther Bull. 2009 Jan;47(1):2-6.
- Nelson H; Menopause. Lancet. 2008 Mar 1;371(9614):760-70. Review
- Menopause, Clinical Knowledge Summaries (January 2008)
- McKee J, Warber SL; Integrative therapies for menopause. South Med J. 2005 Mar;98(3):319-26.
- Daley A, MacArthur C, Mutrie N, et al; Exercise for vasomotor menopausal symptoms. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD006108.
- Rossouw JE, Anderson GL, Prentice RL, et al; Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial. JAMA. 2002 Jul 17;288(3):321-33.
- Sicat BL, Brokaw DK; Nonhormonal alternatives for the treatment of hot flashes. Pharmacotherapy. 2004 Jan;24(1):79-93.
- Butt DA, Lock M, Lewis JE, et al; Gabapentin for the treatment of menopausal hot flashes: a randomized controlled trial. Menopause. 2008 Mar-Apr;15(2):310-8.
- Geller SE, Studee L; Botanical and dietary supplements for menopausal symptoms: what works, what does not. J Womens Health (Larchmt). 2005 Sep;14(7):634-49.
- Lethaby AE, Brown J, Marjoribanks J, et al; Phytoestrogens for vasomotor menopausal symptoms. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD001395.
- Carroll DG; Nonhormonal therapies for hot flashes in menopause. Am Fam Physician. 2006 Feb 1;73(3):457-64.
- Haimov-Kochman R, Hochner-Celnikier D; Hot flashes revisited: pharmacological and herbal options for hot flashes management. What does the evidence tell us? Acta Obstet Gynecol Scand. 2005 Oct;84(10):972-9.
- Barton DL, Loprinzi CL, Quella SK, et al; Prospective evaluation of vitamin E for hot flashes in breast cancer survivors. J Clin Oncol. 1998 Feb;16(2):495-500.
- Coope J, Williams S, Patterson JS; A study of the effectiveness of propranolol in menopausal hot flushes. Br J Obstet Gynaecol. 1978 Jun;85(6):472-5.
- Acupuncture for menopausal hot flushes, Bandolier, February 2005
- Cho SH, Whang WW; Acupuncture for vasomotor menopausal symptoms: a systematic review. Menopause. 2009 May 6.
- Sloan JA, Loprinzi CL, Novotny PJ, et al; Methodologic lessons learned from hot flash studies. J Clin Oncol. 2001 Dec 1;19(23):4280-90.
- Keefer L, Blanchard EB; Hot flash, hot topic: conceptualizing menopausal symptoms from a cognitive-behavioral perspective. Appl Psychophysiol Biofeedback. 2005 Mar;30(1):75-82.
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Dr Colin Tidy
Dr Hayley Willacy