MONDAY, Feb. 17, 2014 (HealthDay News) -- Women suffering from hot flashes might get some relief through an injection of an anesthetic near a nerve bundle in the neck, a small new study finds.
This technique, called a stellate ganglion block, is a common treatment for pain and might be an alternative for women who can't take or are reluctant to take hormone replacement therapy, the researchers said.
"Women are looking for nonhormonal alternatives for hot flashes," said senior researcher Pauline Maki, an associate professor of psychiatry and psychology at the University of Illinois at Chicago.
Maki said some women who had a stellate ganglion block to relieve pain also reported a decrease in the frequency and intensity of their hot flashes, which is what led to this study.
"The findings from our study provide some compelling data that this procedure may offer women a novel, nonhormonal approach to controlling their hot flashes," she said.
The procedure isn't painless, and the most common side effect is pain at the injection site. "If a woman wants to try this procedure, she needs to go to a trained anesthesiologist," Maki said.
The study, which received support from the U.S. National Institutes of Health and Northwestern University, was published recently in the online edition of the journal Menopause.
Dr. Margery Gass, executive director of the North American Menopause Society, said, "stellate ganglion block is a very exciting area for research for treatment of moderate to severe hot flashes."
Gass said many women -- particularly those with breast cancer -- might find stellate ganglion block an acceptable alternative to hormone therapy or antidepressants such as Paxil, which have been approved to treat hot flashes.
More research is needed, however, to see how well stellate ganglion block stacks up against other treatments, she said.
"These initial reports beg for larger and longer studies," Gass said. "We want to know how long the treatment lasts, how often it would need to be repeated, whether this is the ideal dose and if hot flashes return. We don't know the answers to these questions."
Not everyone sees the benefit of the nerve-block procedure.
"It's great that it decreases the number of severe hot flashes, but patients still have hot flashes a lot of times per day," said Dr. Jennifer Wu, an obstetrician/gynecologist at Lenox Hill Hospital in New York City. "That's still really disruptive."
"I am not sure that a majority of patients will want to try this therapy," she said.
For the study, Maki's group randomly assigned 40 women, aged 30 to 70, with moderate to severe hot flashes to receive either stellate ganglion block or a fake treatment with a plain saline solution.
On average, these women had 10 hot flashes a day, with two-thirds either moderate or severe. Moderate hot flashes were defined as those lasting up to 15 minutes with symptoms such as perspiration, clammy skin, dry mouth, tense muscles and rapid heartbeat.
Severe hot flashes were those lasting up to 20 minutes with symptoms such as "raging furnace" warmth, weakness, feeling faint, extreme perspiration and heart irregularities.
For six months, the women reported the frequency and severity of their hot flashes. In addition, for the first three months after treatment, the women wore a monitor that objectively measured hot flashes.
Although the total number of hot flashes was about the same in both groups, the number of moderate to severe hot flashes was significantly reduced among the women given the nerve block, the researchers found.
The number of moderate to severe hot flashes was cut by 52 percent among women who got the nerve block, compared with 4 percent for women who got the fake injection, the researchers said.
What's more, the intensity of the hot flashes was cut by 38 percent for the women who got the nerve block, compared with 8 percent for those given the placebo injection, the researchers said.
"We don't know why this works, but it opens up new avenues for exploring the generation of hot flashes," Maki said. Moreover, the findings might lead to new ways to treat hot flashes, she added.
The researchers said they would like to do a study among women with breast cancer -- for whom hormone therapy for hot flashes is not recommended -- to see if a stellate ganglion block could be an alternative treatment, Maki said.
"[Women with breast cancer] experience more hot flashes than other women, and, unfortunately, they can't take hormone therapy," she said. "That will be the group that will likely benefit most from this."
For more about hot flashes, visit the North American Menopause Society.