"If a woman with osteoarthritis starts HRT and notices that her pain is getting worse, she should consider getting off the drug, taking a lower dose, or switching to another alternative to see if (it is) responsible," he says.

From arthritis to migraines, scientists are also finding sex differences in how men and women respond to the pain of common diseases and disorders:

• Arthritis: Daily logs kept by 71 arthritis patients showed that women experienced significantly more severe pain. According to Keefe, who was principal investigator on the project, women are also more likely to relax, air their emotions, seek distractions and emotional support to cope. "Men don't show their feelings and don't seek out assistance as readily as women. That may very well be what's going on in this case," Keefe says.
• Cardiac Disease: Premenopausal women have higher rates of false-positive chest pain syndromes, while postmenopausal women have relatively high rates of asymptomatic or silent heart disease, says Debra Judelson, MD, medical director of the Women's Heart Institute in Beverly Hills, Calif. and former president of the American Women's Medical Association. "Women are more likely to have high blood pressure and diabetes as complicating medical problems which can change the way they experience pain," Judelson says. "They also have more abdominal, shoulder, and neck pain, shortness of breath, back discomfort, vomiting, fatigue and nausea as opposed to chest discomfort seen in men." The bottom line: up to a 40 percent higher mortality rate in younger women under 50 with heart disease than men. "Whatever symptoms they experience are not recognized as a cardio problem in the emergency room, which contributes to delays in seeking help or getting treatment," Judelson adds.
• Migraine Headaches: Boys have more migraines than girls until puberty when hormones begin kicking in. Women are three times more likely to experience migraines than men beginning at puberty when hormone fluctuations kick in. They seem to strike whenever estrogen, the neurotransmitter serotonin, and beta endorphins are low. Several studies concluded that migraine in women of childbearing age dramatically boosts the risk of ischaemic, not haemorrhagic stroke. Women who use oral contraceptives, have high blood pressure, or smoke are at greatest risk of ischaemic stroke associated with migraine.

Opioids More Effective in Women
Scientists believe that learning about sex differences in pain may require rethinking how much medication to give people based on their sex. A 2001 study found that women patients with myocardial infarction (heart attack) were less likely than men to receive aspirin in the first hour of care than men.

Evidence suggests men and women respond differently to certain drugs, including analgesics used to treat pain. Campbell indicated that one study found that for back pain, male physicians prescribed higher doses of pain medication while female physicians upped pain medication for women. As the founder of the American Pain Society, Campbell urges more, not less, prescribing of painkillers to those in need.

Despite the fact that painful problems disproportionately strike women, the bright side is that a class of pain relievers called opioids are more effective in women although Campbell insists that their effects vary with the menstrual cycle.

To get pain relief, he insists, often calls for a variety of treatments, not a single solution. "The bottom line is helping that person relieve the level of pain and suffering, sleep, and function for daily living." Claw agrees. He prescribes medications that act on neurotransmitters, exercise, and cognitive therapy.