The tranquilizer Xanax can relieve the tension, irritability and aches of severe premenstrual syndrome, University of Pennsylvania Medical Center researchers say.
Their study, published in Wednesday's issue of the Journal of the American Medical Association, also found that the hormone progesterone is not particularly effective in treating PMS, even though it has been widely prescribed for that purpose for more than a decade.
Coming on the heels of a study that found Prozac can help with severe PMS, the new research offers yet more insight into the hormonal and nervous system interactions that trigger the mysterious malady.
"It's one more step in understanding PMS and how to treat it," said Dr. Ellen W. Freeman, a professor of obstetrics and gynecology who led the Penn study. "Not very long ago, there was nothing."
While most women suffer at least mild symptoms of PMS, such as moodiness, fatigue and food cravings, up to 10 percent of women -- about 6 million in all -- experience emotional and behavioral changes that disrupt their lives. The Penn researchers identified 170 severe sufferers and randomly assigned them to take Xanax, progesterone or a placebo.
Of those taking Xanax, 37 percent reported a significant improvement in overall premenstrual symptoms, compared with 29 percent who reported relief on progesterone and 30 percent on placebo.
The effect of Xanax was more striking when the comparison focused on emotional, mental and certain physical symptoms, including irritability, anxiety, mood swings, fatigue, insomnia, cramps and headaches.
For some women, Xanax may offer advantages over Prozac, Dr. Freeman said. Xanax proved effective when taken for about two weeks of the month; Prozac, in contrast, was taken every day. Xanax also has relatively milder side effects.
Xanax is known to cause dependency when taken for long periods, but because PMS treatment was restricted to two weeks, women in the study suffered no withdrawal problems.