Men and women experience pain differently
Posted by on September 11, 2011 - 6:49am

Women and men experience pain, particularly chronic pain, very differently. The ability of some opioids (painkillers that work similar to opium/morphine) to relieve pain also differs between sexes. While it has been recognized since the mid-nineties that some narcotic analgesics are more effective in women than men, the reason for this difference was largely unknown.

Narcotic painkillers (analgesics)  decrease pain by activating opioid receptors, which are located on nerves that transmit painful sensations. There are 4 major subgroups of opioid receptors:  delta, kappa, mu and Nociceptin, and each is involved in controlling different functions of the brain. Since levels of mu, delta, and kappa opiate receptors - the three main types of opioid receptor in the brain and spinal cord - are not thought to differ dramatically in men and women, it was difficult to understand why the effectiveness of some painkillers is dependent on sex.

Now, research supported by the National Institute of Drug Abuse (NIDA) has revealed that the same major types of opioid receptor interact differently, depending on sex. The spinal cord of female laboratory animals was found to contain almost five times more kappa-mu heterodimer (a complex formed by two different macromolecules bound together, e.g, mu-opioid and kappa-opioid receptor) than the spinal cord of male animals. Furthermore, the amount of mu-kappa heterodimer in the spinal cord of the females was about four times higher when their levels of estrogen and progesterone were at their peak. Subsequently, researchers found that both estrogen and progesterone are critical for the formation of mu-kappa opioid receptor heterodimers.

The discovery of a mu-kappa opioid receptor complex that is more prevalent in the spinal cord of females than males and that is synchronized with the ebb and flow of ovarian hormones could explain why drugs used to treat pain, such as pentazocine, nalbuphine, and butorphanol - which primarily act on mu-opioid and kappa-opioid receptors - are more effective in women than men. The activation of the kappa-opioid receptor within the kappa-mu-opioid receptor complex could provide a mechanism for recruiting the pain-relieving functions of spinal kappa-opioid receptors without also activating their pain-promoting functions.

The research by Drs. Gintzler, Liu, and Chakrabart from State University of New York (SUNY) Downstate Medical Center, suggests that kappa-mu opioid receptor heterodimers could function as a molecular switch that shifts the action of kappa-opioid receptors and endogenous chemicals that act on them from pain-promoting to pain-alleviating. Kappa-mu opioid receptor heterodimers could serve as a novel molecular target for pain management in women.

Dr. Gintzler's research suggests that physicians should take the stage of the menstrual cycle into account before deciding which drugs to prescribe to treat pain in women. While some drugs might be very effective in treating pain at times when estrogen and progesterone levels are high, they could heighten pain when levels are low. "This consideration could become even more critical in managing pain in postmenopausal and elderly women," said Dr. Gintzler. "Further research is needed to flesh out these possibilities."

Article References:  The Journal of Neuroscience August 17, 2011 edition.

 

 

Understanding the Science of Acupuncture
Posted by on February 21, 2011 - 10:33am

Acupuncture is a traditional medicine that’s been practiced in China and other Asian countries for thousands of years. Its proponents say it can do everything from relieving pain to bringing a general sense of wellness. Others think the only benefits you get from acupuncture are in your head. Recent studies have found that both sides may have a point. Acupuncture can be effective for certain health problems, such as some types of chronic pain. But how it works is something of a mystery.

Acupuncture is the stimulation of specific points on the body. The methods can vary, but the most well known type in the United States is the insertion of thin metal needles through the skin. At least 3 million adults nationwide use acupuncture every year, according to the latest estimates.

Acupuncture is part of a family of procedures that originated in China. According to traditional Chinese medicine, the body contains a delicate balance of 2 opposing and inseparable forces: yin and yang. Yin represents the cold, slow or passive principle. Yang represents the hot, excited or active principle. Health is achieved through balancing the 2. Disease comes from an imbalance that leads to a blockage in the flow of qi—the vital energy or life force thought to regulate your spiritual, emotional, mental and physical health. Acupuncture is intended to remove blockages in the flow of qi and restore and maintain health.

Researchers don’t know how these ideas translate to our Western understanding of medicine, explains Dr. Richard L. Nahin of NIH’s National Center for Complementary and Alternative Medicine. But the fact is that many well-designed studies have found that acupuncture can help with certain conditions, such as back pain, knee pain, headaches and osteoarthritis.

“In many research studies, it’s clear that if you’re comparing acupuncture to usual care, the acupuncture group almost always does better,” Nahin says. The problem, he explains, is that when researchers have compared acupuncture to carefully designed “control” treatments, the picture becomes more complicated.

Well-designed clinical trials need control groups—people who get a sham or simulated treatment called a placebo. Placebos might come in the form of a sugar pill or a saline injection. They give researchers something to compare the real treatment with. But designing a placebo for acupuncture is a challenge.

“I don’t really think you can come up with a great placebo needling,” says Dr. Karen J. Sherman, an NIH-funded acupuncture researcher at Group Health Research Institute in Seattle.

For example, when researchers have compared inserting needles with just pressing a toothpick onto acupuncture points, they’ve often found both treatments to be successful. But Sherman questions whether these are really controls. Many traditional acupuncturists would consider them true treatments, too. The important thing, in their view, is to hit the right spot, not necessarily how deep you go.

Another option for a placebo would be to test a different location. But Sherman says that would be inappropriate for treating pain because acupuncturists traditionally needle tender points. “To me, there’s no place on the back, if you have back pain, where you can say you have a great control,” Sherman says, “so I don’t think that’s a really solid idea.”

Further complicating things is that acupuncture treatments are about more than just needles. “There’ll be needles,” Sherman says, “but there’ll probably be other things they do in the course of the treatment. Acupuncturists will talk to you in a particular way. They might give you dietary advice or exercise advice that stems from a non-Western theoretical construct. They’ll try to engage you in your own healing. They might give you a different model for thinking about your health.”

“It’s hard to design placebo-controlled studies of acupuncture when we don’t understand what the active component of the intervention is,” explains Dr. Richard E. Harris, an NIH-funded researcher at the Chronic Pain and Fatigue Research Center in Ann Arbor, Michigan.

Treatment for pain is the best-studied aspect of acupuncture. Many parts of the brain are connected in the processing of pain, and how much pain you feel partly depends on context. “If a person has an injury in battle, they might not feel it,” Sherman explains, “but if they have a similar injury just walking down the street, they might just think it was dreadful.”

“If you look at some of the data, what you find is that sham acupuncture and true acupuncture both produce some pain relief in whatever condition they’re looking at,” Nahin says. “But while both treatments turn on areas of the brain, they turn on different areas of the brain.”

Harris and his colleagues, in studies of fibromyalgia patients, have found differences at the molecular level as well. “We were able to show that sham acupuncture and real acupuncture both reduced pain in fibromyalgia patients equally,” he says, “but they do it by different mechanisms.”

If acupuncture truly works by a different mechanism than sham acupuncture, Harris says, then they’re not the same thing, even if they both help relieve pain. Harris and others are now trying to get to the bottom of what acupuncture is actually doing. Their ultimate goal is to see if other treatments might pair well with acupuncture to reduce pain better than either alone.

Should you try acupuncture? Studies have found it to be very safe, with few side effects. If you’re thinking about it, talk to your doctor. “We tell people they really need to talk to their primary care provider and discuss whether acupuncture is a viable option for them,” Nahin says. “While you could go to an acupuncturist independent of a medical practitioner, we feel that an integrated approach to care is always the best approach.”

“Find somebody who’s dealt with your problem before,” Sherman advises. “Talk to the practitioner about your specific situation and then see if it’s something you can live with because it might not be the right treatment for you.”

If you do decide to try acupuncture, she adds, “You need to know that you should give it some time. You can’t expect one session will tell you whether it works or not. Be open minded and willing to at least entertain some of the notions that the acupuncturist brings up. Give it a try if you’re open to it.”

If You Want to Try Acupuncture

Talk to your health care provider about it, especially if you’re pregnant or nursing, or are thinking of using acupuncture to treat a child.
Find an acupuncturist who’s experienced working with your problem.
Check credentials. Most states require a license to practice acupuncture.
Don’t use acupuncture as a replacement for conventional care.
Don’t rely on a diagnosis of disease by an acupuncturist who doesn’t have conventional medical training.
To help ensure coordinated and safe care, tell your health care providers about any complementary and alternative practices you use.

Source:  NIH Office of Communications
and Public Liaison

Yoga Combats Fibromyalgia
Posted by on November 1, 2010 - 2:22pm

According to new research conducted at Oregon Health & Science University, yoga exercises may have the power to combat fibromyalgia — a medical disorder characterized by chronic widespread pain. The research is being published in the November 10 edition of the journal Pain and will appear online Thursday, Oct. 14.

Fibromyalgia is a syndrome predominantly characterized by muscle pain and fatigue. It can cause sleep problems and psychological stress. Other symptoms often include morning stiffness, tingling or numbness in the extremities, headaches, memory problems, difficulty with swallowing, and bowel and bladder problems.  Fibromyalgia affects between 11 million and 15 million Americans with 85-90% of the cases in women.  The cause of fibromyalgia is currently unknown, but it is believed that genetics and physical/emotional stress may play a role.

“Previous research suggests that the most successful treatment for fibromyalgia involves a combination of medications, physical exercise and development of coping skills,” said James Carson, Ph.D., a clinical health psychologist and an assistant professor of anesthesiology and perioperative medicine in the OHSU School of Medicine. “Here, we specifically focused on yoga to determine whether it should be considered as a prescribed treatment and the extent to which it can be successful.”

In this study, researchers enrolled 53 female study subjects previously diagnosed with fibromyalgia. The women were randomly assigned to two research groups. The first group participated in an eight-week yoga program, which included gentle poses, meditation, breathing exercises and group discussions. The second group of women — the control group — received standard medication treatments for fibromyalgia.

Following completion of the yoga program, researchers assessed each study subject using questionnaires and physical tests. The results were then compared with testing results obtained prior to the yoga classes. The members of the control group underwent the same evaluations. In addition, each participant in the yoga group was urged to keep a daily diary to personally assess their condition throughout the entire program.

Comparison of the data for the two groups revealed that yoga appears to assist in combating a number of serious fibromyalgia symptoms, including pain, fatigue, stiffness, poor sleep, depression, poor memory, anxiety and poor balance. All of these improvements were shown to be not only statistically but also clinically significant, meaning the changes were large enough to have a practical impact on daily functioning. For example, pain was reduced in the yoga group by an average of 24 percent, fatigue by 30 percent and depression by 42 percent.

“One likely reason for the apparent success of this study therapy was the strong commitment shown by the study subjects. Attendance at the classes was good as was most participants’ willingness to practice yoga while at home,” added Carson. “Based on the results of this research, we strongly believe that further study of this potential therapy is warranted.”

Botox for Chronic Migraines
Posted by on October 20, 2010 - 9:10am

On October 15, 2010, the U.S. Food and Drug Administration approved Botox injection (onabotulinumtoxinA) to prevent headaches in adult patients with chronic migraine. Chronic migraine is defined as having a history of migraine and experiencing a headache on most days of the month.   it is estimated that about 6% of men and 18% of women suffer from migraine headaches during any given year.

“Chronic migraine is one of the most disabling forms of headache,” said Russell Katz, M.D., director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research. “Patients with chronic migraine experience a headache more than 14 days of the month. This condition can greatly affect family, work, and social life, so it is important to have a variety of effective treatment options available.”

Migraine headaches are described as an intense pulsing or throbbing pain in one area of the head. The headaches are often accompanied by nausea, vomiting, and sensitivity to light and sound. Migraine is three times more common in women than in men. Migraine usually begins with intermittent headache attacks 14 days or fewer each month (episodic migraine), but some patients go on to develop the more disabling chronic migraine.

To treat chronic migraines, Botox is given approximately every 12 weeks as multiple injections around the head and neck to try to dull future headache symptoms. Botox has not been shown to work for the treatment of migraine headaches that occur 14 days or less per month, or for other forms of headache. It is important that patients discuss with their physician whether Botox is appropriate for them.

The most common adverse reactions reported by patients being treated for chronic migraine were neck pain and headache (NOTE from this blogger:   FDA should define what kind of headache---treat migraine headaches with a medicine that may cause headaches???).

OnabotulinumtoxinA, marketed as Botox and Botox Cosmetic, has a boxed warning that says the effects of the botulinum toxin may spread from the area of injection to other areas of the body, causing symptoms similar to those of botulism. Those symptoms include swallowing and breathing difficulties that can be life-threatening. There has not been a confirmed serious case of spread of toxin effect when Botox has been used at the recommended dose to treat chronic migraine, severe underarm sweating, blepharospasm, or strabismus, or when Botox Cosmetic has been used at the recommended dose to improve frown lines.