There is no question that doctors use morphine this way. ''It happens all the time,'' said Dr. John M. Luce, a professor of medicine and anesthesiology at the University of California in San Francisco. And there is no question that most doctors think that morphine can hasten a patient's death by depressing respiration.
But Dr. Luce and others are asking whether morphine and similar drugs really speed death. Experts in palliative care say the only available evidence indicates that morphine is not having this effect.
Dr. Balfour Mount, a cancer specialist who directs the division of palliative care at McGill University in Montreal, firmly states that it is ''a common misunderstanding that patients die because of high doses of morphine needed to control pain.''
No one denies that an overdose of morphine can be lethal. It kills by stopping breathing. But, said Dr. Joanne Lynn, director of the Center to Improve Care of the Dying at George Washington University School of Medicine, something peculiar happens when doctors gradually increase a patient's dose of morphine.
The patients, she said, become more tolerant of the drug's effect on respiration than they do of its effect on pain. The result, Dr. Lynn said, is that as patients' pain gets worse, they require more and more morphine to control it. But even though they end up taking doses of the drug that would quickly kill a person who has not been taking morphine, the drug has little effect on these patients' breathing.
Dr. Kathleen Foley, who is co-chief of the pain and palliative care service at Memorial Sloan-Kettering Cancer Center in New York, said that she routinely saw patients taking breathtakingly high doses of morphine yet breathing well. ''They're taking 1,000 milligrams of morphine a day, or 2,000 milligrams a day, and walking around,'' she said. The standard daily dose used to quell the pain of cancer patients, she added, is 200 to 400 milligrams.
Dr. Lynn said she sometimes gave such high doses of morphine or similar drugs that she frightened herself. She remembers one man who had a tumor on his neck as big as his head. To relieve his pain, she ended up giving him 200 milligrams of a morphine-like drug, hydromorphone, each hour, 200 times the dose that would put a person with no tolerance to the drug into a deep sleep.
''Even I was scared,'' Dr. Lynn said, but she found that if she lowered the dose to even 170 milligrams of the drug per hour, the man was in excruciating pain. So to protect herself in case she was ever questioned by a district attorney, she said, she videotaped the man playing with his grandson while he was on the drug.
On rare occasions, Dr. Lynn said, she became worried when she escalated a morphine dose and noticed that the patient had started to struggle to breathe. Since she did not intend to kill the patient, she said, she administered an antidote. But invariably, she said, she found that the drug was not causing the patient's sudden respiratory problem. One man, for example, was having trouble breathing because he had bled from a tumor in his brain, and an elderly woman had just had a stroke. ''In every single case, there was another etiology,'' Dr. Lynn said.
''Joanne's experience is emblematic,'' said Dr. Russell K. Portenoy, the other co-chief of the pain and palliative care service at Memorial Sloan-Kettering Cancer Center. He said he was virtually certain that if doctors ever gave antidotes to morphine on a routine basis when dying patients started laboring to breathe, they would find that Dr. Lynn's experience was the rule. Patients generally die from their diseases, not from morphine, Dr. Portenoy said.
The actual data on how often morphine and other opiates that are used for pain relief cause death are elusive. But Dr. Foley and others cite three studies that indirectly support the notion that if morphine causes death, it does so very infrequently.
One study, by Dr. Frank K. Brescia of Calvary Hospital in the Bronx and his colleagues, examined pain, opiate use and survival among 1,103 cancer patients at that hospital, which is for the terminally ill. The patients had cancer that was ''very far advanced,'' said Dr. Portenoy, an author of the paper. But to his surprise, he said, the investigators found no relationship between the dose of opiates a patient received and the time it took to die. Those receiving stunningly high doses died no sooner than those taking much lower doses.
Another study, by Dr. Luce and his colleagues in San Francisco, looked at 44 patients in intensive care units at two hospitals who were so ill that their doctors and families decided to withdraw life support. Three-quarters of the patients were taking narcotics, and after the decision was made to let them die, the doctors increased their narcotics dose. Those who were not receiving opiates were in comas or so severely brain-damaged that they did not feel pain.
The researchers asked the patients' doctors to tell them, anonymously, why they had given narcotics to the patients and why they had increased the doses. Thirty-nine percent of the doctors confided that, in addition to relieving pain, they were hoping to hasten the patients' deaths.
But that did not seem to happen. The patients who received narcotics survived an average of 3 1/2 hours after the decision had been made to let them die. Those who did not receive narcotics lived an average of 1 1/2 hours. Of course, Dr. Luce said, the study was not definitive because the patients who did not receive drugs may have been sicker and more likely to die very quickly. Nonetheless, he said, the investigators certainly failed to show that narcotics speeded death.
Dr. Declan Walsh, the director of the Center for Palliative Medicine at the Cleveland Clinic, said it had been 15 years since he first questioned the assumption that morphine used for pain control killed patients by depressing their respiration. He was working in England at the time, and many doctors there were afraid to prescribe morphine or similar drugs for cancer patients, Dr. Walsh said, because ''they were afraid they would kill the patients.''
So Dr. Walsh looked at carbon dioxide levels in the blood of cancer patients on high doses of morphine to control their pain. If their breathing was suppressed, their carbon dioxide levels should have been high. But they were not. Nonetheless, Dr. Walsh said, the idea that morphine used for pain relief depresses respiration is widely believed by doctors and nurses because it is ''drummed into them in medical school.''
So, said Dr. Susan Block, a psychiatrist in the hematology and oncology division at Brigham and Women's Hospital in Boston, it is not surprising that many doctors try to use morphine to speed dying.
''There is more and more evidence -- most of it unpublished, but it's coming, I've seen it -- that physicians, in addition to wanting to ease patients' discomfort, also want to hasten death,'' Dr. Block said. ''Everyone is feeling guilty.''
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