Painkillers, usually given only after surgery, may do their best work before the pain begins, a new study suggests.
The study, to be presented today to the American Society of Anesthesiologists convention in New Orleans, looked at the theory that feeling pain “winds up” nerves, making them more sensitive.
Doctors believe they may be able to minimize pain by stopping it before it starts.
“If you stub your toe, portions of the foot might hurt for days because the blow sensitizes that part of the nervous system,” said Dr. Allan Gottschalk of the University of Pennsylvania School of Medicine. “The same thing happens when you have surgery.”
To test whether giving painkillers before an operation could prevent pain afterwards, Gottschalk studied 90 men, most in their 50s, whose prostate glands were being removed because of cancer.
They were divided into three groups: Two experimental groups got different painkillers both before and after surgery, while a control group received the pain medicine only afterward.
One experimental group was given a narcotic, the other got a local anesthetic. All of the painkillers, before and after surgery, were delivered by catheter into the spine.
During each day of their hospital stay, the men were asked to gauge their pain on a 100-millimeter slide rule with a smiling face at zero and a frowning face at 100. Those in the control group reported significantly more pain than those in the two experimental groups.
“This is important,” said Dr. Daniel I. Sessler, an anesthesiologist at the University of California at San Francisco.
The “windup” theory that pain activates nerves and spinal pathways that regulate pain, and thus make them more sensitive, is only a few years old, he said.
“If that’s true, preventing pain should be more useful than treating pain before you have it,” Sessler said.
He noted that some studies have found no differences between groups given pre-emptive painkillers and those who only took drugs afterward, but said, “they may not have found true differences because they didn’t study enough patients.”
Gottschalk also looked at whether taking painkillers early had any long-term effects by calling the men 3{, 5{ and 9{ weeks after they left the hospital.
The men from the three groups reported no significant difference at the two earlier time periods, he said.
But 9{ weeks later, 81 percent of the experimental group members were feeling no pain and had returned completely to work and other normal activities. Only 44 percent of the control group was pain-free.
Sessler said that delayed difference was much more likely to be random than the differences found in the hospital, but Gottschalk said the likelihood of its being due to chance was only one in 500.
Dr. Alan W. Grogono, chairman of Tulane Medical School’s anesthesiology department, said the possibility of such long-term pain relief is definitely worth more study.
“It’s slightly surprising that the differences weren’t detectable in the interval before going back to work. But certainly getting back to work and achieving the normal routines is an important yardstick,” he said.
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