Findings could bring new treatment options for patients, researchers say
MONDAY, Oct. 15 (HealthDay News) -- Surgery patients may one day find nicotine patches or hot pepper-based chemicals on their pain prescription pad, researchers say.
Nicotine patches and the hot pepper-derivative capsaicin both provided pain relief following surgery, according to two studies presented at the American Society of Anesthesiologists' annual meeting, which concludes Wednesday.
Neither pain-management approach had serious side effects for the people in the studies, although those using the nicotine patches reported increased nausea. But, perhaps not surprisingly, other studies have shown that capsaicin often causes a burning sensation at the site of its application.
In the first study, researchers at Duke University gave 90 non-smoking men who were undergoing prostate removal surgeries a 7-milligram nicotine patch or an identical nicotine-free patch before anesthesia and surgery. After surgery, each patient was able to control their pain by adjusting a morphine drip.
The men who received the nicotine patch chose to self-administer less morphine during the 24 hours following surgery than the men whose patches did not contain nicotine. Both groups rated their pain at similar levels, the study found.
The researchers noted that other than the reported nausea, nicotine apparently relieved pain without the narcotic side effects associated with morphine.
"The issue of nausea could be addressed by using more aggressive prophylaxis against postoperative nausea and vomiting. For instance, in this study we used prophylaxis with one agent. It is known that using a combination of [anti-nausea drugs] is more effective than using one agent," said lead author Dr. Ashraf Habib, associate professor of anesthesiology and director of quality improvement at Duke University Medical Center.
Other options, including longer term release patches or lower dose patches, might ease the nausea, Habib said. "The use of nicotine for perioperative analgesia also needs to be studied in smokers, who are unlikely to suffer from the side effect of nausea," he said.
Nicotine patches are approved for use to help smokers quit cigarettes. However, previous studies have shown that nicotine also has some pain-relief benefits. In an earlier study, women who were given a nasal spray containing 3 milligrams of nicotine after a hysterectomy reported less pain or need for morphine, the Duke researcher said.
It's important to note that this study addressed pain related to surgery, not chronic pain, said Edwin W. McClesky, scientific officer at the Howard Hughes Medical Institute, in Chevy Chase, Md., who was not involved with the research. Nicotine patches aren't an answer for chronic pain sufferers, he said.
"Nicotine is a poor solution for anything because it is so addictive," McClesky said. The mechanism by which nicotine may help manage pain after surgery isn't yet known, he added, "because there are nicotine receptors in both the central and peripheral nervous systems."
Habib said short-term analgesic use of nicotine is not addictive. He said future studies will address different doses of nicotine and the drug's effect in different groups of people, such as smokers and women.
In the second study, researchers in Denmark found that purified capsaicin -- a colorless, odorless drug derived from chili peppers -- provided three days of pain relief for men recovering from hernia surgeries.
The researchers placed 1,000 micrograms of purified capsaicin directly into the wounds of approximately 20 men during surgery. The researchers compared the men's postoperative pain with another 20 men who underwent surgery with a placebo instead of capsaicin. Patients in the capsaicin group had significantly lower pain scores during the three days following surgery, the study authors said.
"We were expecting an analgesic effect from capsaicin and were pleased to see it," said study author Dr. Eskve Aasvang, an anesthesiology research fellow at the Juliana Marie Center, in Copenhagen. "Capsaicin is a very potent inhibitor of the c-nerve fiber, which is responsible for sharp, shooting, burning pain. However, because pain scores were very low and short-lasting in both the capsaicin and placebo group, the potential effect of capsaicin of up to six weeks could not be assessed."
Capsaicin is already used in an ointment for treating shingles, said Aasvang. While taking capsaicin by mouth has not been shown to be effective in reducing pain, different chronic pain conditions, such as shingles and osteoarthritis, may benefit from local application, but Aasvang said these approaches need further research.
In a study released earlier this month, researchers at Harvard Medical School showed that a combination of capsaicin and the lidocaine derivative QX-314 blocked pain in rats, suggesting that people may one day have an alternative to lidocaine during dental surgery without additional numbness or localized paralysis.
To learn more about pain management, visit the U.S. National Library of Medicine.
SOURCES: Eske Aasvang, M..D, anesthesiology research fellow, Juliana Marie Center, Copenhagen, Denmark; Ashraf S. Habib, MB, BCh, MSc, FRCA, associate professor of anesthesiology, Director of Quality Improvement, Duke University Medical Center, Durham, N.C.; Edwin W. McClesky, PhD, scientific officer, Howard Hughes Medical Institute, Chevy Chase, Md.; presentations, American Society of Anesthesiologists annual meeting, San Francisco, Oct. 14, 2007
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