Cancer patients who got morphine at the touch of a button to relieve pain stopped using the drug sooner, and used little more than half the narcotic than patients who got a continuous infusion, a researcher says.
"These patients don't even come close to developing addiction," said C. Richard Chapman, associate research director at the Pain Center of the University of Washington and director of the pain and toxicity research program at the Fred Hutchinson Cancer Research Center in Seattle.
The shorter time on the drug is important because it means an earlier end to confusion, sedation and other unpleasant reactions that accompany morphine treatment, he said.
"In order to cope you need all your marbles. You can't be coping effectively when you're on the drug," he said.
He spoke in a recent interview about research done with Hutchinson colleagues including Harlan Hill, Costantino Benedetti and others.
They studied hospitalized patients who had undergone bone marrow transplantation as part of cancer therapy. As a result of cancer treatment, such patients commonly suffer pain for two or three weeks in the mouth and through the digestive tract, and sometimes in the hands and feet and elsewhere, Chapman said.
In the study, 32 patients got a continuous infusion of morphine through an intravenous line, the standard treatment, Chapman said. Twenty-six others got doses by pushing a button on an electric pump hooked up to an intravenous line.
The pump was programmed to give no more than 1 milligram of morphine every 10 minutes. For each group, the decision to stop treatment was made jointly between the patient and medical staff, Chapman said.
Patients who controlled their morphine used the drug an average of about 13 days, while those who received a continuous intravenous infusion averaged more than 17 days.
Used 53% as Much
The self-administering group also used only 53% as much morphine as the other patients.
While the study was not designed to look for addiction, no self-administering patient reported cravings for the drug after the treatment stopped, Chapman said.
Self-administration of drugs might be useful for prolonged pain of serious burns or terminal stages of cancer, he said. It would not be suitable for pain that lasts for years, such as some cases of low back pain, he said.
So-called "patient-controlled analgesia" has been studied extensively for short-term pain like that following surgery. But the new work is the first large-scale study involving long-term pain, said Richard Payne, associate professor of neurology at the University of Cincinnati.
Safe Control by Patients
The study is important because it shows patients can safely control the amount of drug they get, gaining relief without overdosing, he said.