By Harvey B. Simon, M.D. Harvard Medical School
Men who see their female companions flush and sweat when they reach a certain age are probably glad they won't get postmenopausal hot flashes. But hot flashes are not just a woman's problem. In fact, some men can be just as troubled. Most men and women whose lives are disrupted by flashes can benefit from new approaches to therapy.
Who Has Hot Flashes -- and Why?
Doctors understand the who more than the why. In both men and women, hormones are to blame. About 70% of women get hot flashes at the time of menopause, when estrogen levels plummet.
In men, the problem is testosterone. Males don't experience an abrupt drop in the hormone. In fact, although testosterone levels trickle down by about 1% a year after the age of 40, most men maintain levels within the normal range. And nearly all retain enough testosterone to prevent hot flashes.
The big exception is men who've received androgen deprivation therapy for prostate cancer. The growth of prostate cells is stimulated by testosterone. Certain drugs can reduce levels of the hormone or block its actions in the body to help treat the disease. Androgen deprivation can be a temporary measure to boost the effect of radiation therapy or it can be a long-term treatment for advanced prostate cancer.
In the past, androgen deprivation was often accomplished by surgical castration, which is permanent, or by administering estrogen in tablet form. At present, though, treatment usually relies on injections that reduce testosterone production, such as leuprolide (Lupron) or goserelin (Zoladex), or drugs that block testosterone's effects on tissues, such as (Casodex).
About 80% of men who receive androgen deprivation therapy have hot flashes. Scientists know that low testosterone can cause hot flashes. But they don’t know why. The body's heat control center is in part of the brain called the hypothalamus. This control center is where hot flashes start. The nervous system sends out signals that cause blood vessels in the skin to widen. This causes flushing and warmth. To counter the rise in skin temperature, the body rapidly converts a warm flush to a cold, clammy sweat.
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Hot flashes feel the same to men and women: a sudden feeling of warmth or flushing that is most intense over the head and trunk. It is often accompanied by visible redness of the skin and by sweating, which can be profuse.
Hot flashes are most common at night. They are usually brief, averaging four minutes, but they often leave cold sweat behind. Flashes may be infrequent and mild or quite troublesome. In severe cases, they occur 6 to 10 times a day. Some men and women report anxiety, palpitations or irritability. Drenching night sweats may occur.
Most women get over their hot flashes in a year or so, even without therapy. Others are troubled for years.
Men who develop flashes during temporary androgen deprivation usually recover within three or four months of stopping treatment. Doctors often tell patients on long-term androgen deprivation that they will also get over the problem, but most don't. In one study, over 40% of men still had flashes after more than 8 years of treatment. In another, 77% of patients said the hot flashes interfered with sleep and 59% reported they interfered with the ability to enjoy life. Fortunately, new treatments can help.
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Until hormone therapy (HT) lost its blush, many women relied on estrogens to treat hot flashes. HT is effective, but it can increase the risk of breast cancer, heart attack, stroke and blood clots. The additional risk is relatively small, and some women still use HT for severe hot flashes. Others have tried antihypertensive medications, soy, vitamins and other remedies without much success. Acupuncture and other alternative therapies have generally been disappointing.
Men with prostate cancer cannot take testosterone, but they can use female hormones for hot flashes. In one study, 83% of men who tried estradiol (an estrogen) reported relief. But 42% experienced breast swelling or tenderness. And the clinical trial was too brief to rule out the possibility of heart problems that plagued earlier experience with estrogen use in men. Studies using the female hormone progesterone — megestrol (Megace) and medroxyprogesterone (Provera) — have reported up to 92% reductions in hot flashes. But the side effects can include bloating and weight gain; in addition, the hormone appears to increase prostate-specific antigen (PSA) levels in some patients.
Hormones can help, but newer treatments may be just as successful with fewer side effects. Two approaches have helped both men and women.
- Selective serotonin reuptake inhibitors (SSRIs) – Antidepressant medicines, such as paroxetine (Paxil) and a related antidepressant, venlafaxine (Effexor), are well tolerated. Venlafaxine can sometimes raise the blood pressure. SSRIs can cause sexual dysfunction, but that's not an issue for most men on androgen deprivation.
- The anti-seizure medication gabapentin (Neurontin) was first used to reduce hot flashes in men, but it rapidly gained wider use in women. In one study, the drug reduced hot flashes by 70%; dizziness is the most common side effect.
About 70% of women develop hot flashes about the time of menopause. Men are not immune; if nothing else, the occurrence of hot flashes in some men with prostate cancer should remind all men to stay cool when females flush.
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Harvey B. Simon, M.D. is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.