NEW YORK--The "right" dose of pain medication is the one that works, Ronald Blum, MD, said at a conference on cancer pain sponsored by Cancer Care, Inc. But that simple maxim is not so easy to follow.
NEW YORK--The "right" dose of pain medication is theone that works, Ronald Blum, MD, said at a conference on cancerpain sponsored by Cancer Care, Inc. But that simple maxim is notso easy to follow.
Cancer pain is complex, and treating it involves routinely assessinga patient's pain. "Clearly, one of the barriers is that wedon't ask our patients, Hello, how are you? How do you feel? Areyou in pain?" said Dr. Blum, deputy director, Kaplan ComprehensiveCancer Center, New York University Medical Center.
"We need to assess the location of the pain, the temporalpattern, and the quality, to differentiate between somatic pain,nociceptive pain, in particular, and neuropathic pain. Questionssuch as, What makes the pain worse, What makes it better, helpus decide on interventions."
Dr. Blum and his patients use a visual analogue scale rated from1 to 10 to communicate about pain. "My patients will comein, and I'll say, how are you? And they'll say--Five. We've establisheda way of communicating. You can apply the same concept to establishingthe relief of a particular intervention. They'll say--I got afour out of it."
Cancer pain is "different," Dr. Blum said, in that thereis a known pathology, patients may have more than one site ofdisease, and there may be multiple etiologies. The pain couldbe from the treatment, the disease, or a mixture of the two. Patientsalso bring their pre-cancer pain history of varying durationsand patterns, he said.
Some types of pain may have reversible causes, and cliniciansshould look out for them, Dr. Blum said. "A physical examinationis essential, as well as appropriate laboratory, radiologic, andpathologic diagnoses. I can't tell you how embarrassing it isfor everyone when I am asked to see a patient who has, say, severeunrelieved hip pain, and all I do is roll back the sheet and seethat the patient has a fracture of the hip that has gone unnoticed."
Though acute pain and subacute pain are generally well managed,chronic pain is not, he argued, and these patients outnumber thosewith acute pain. "The real clinical impact is in the managementof chronic pain," he said. "We all see patients withrelatively severe pain who are getting relatively mild analgesics."
While the problem of undertreatment lies primarily in the lackof pain assessment, faulty perception also plays a role, saidDr. Blum, who coauthored a study of cancer pain published in theNew England Journal of Medicine 2 years ago. In that study, hefound that physicians tend to undertreat pain, particularly inpatients who look well or are older, female, or a member of aminority group.
Using the metaphor of cancer as a stepladder in which pain getsworse as patients go up the ladder of disease, Dr. Blum said thatpain is least well controlled midpoint on the ladder. "Physicianstend to start out with very low analgesic doses and continue toundertreat patients as they go up the pain ladder."
The side effects of morphine and other narcotic analgesics (sedation,sleepiness, nausea, vomiting) should not dissuade physicians fromprescribing opioids or patients from taking them. Patients shouldbe reassured that they will not become addicted (see box below)and will soon tolerate most of the side effects of the drug, Dr.Blum advised.
"It will take a few days or a week, but what has to be guardedagainst is the per-son who says--'I took one dose. It made menauseous. I'm not taking it again. I'm allergic to it.' Quitethe opposite. People do become tolerant to the side effects, butnot to the analgesic properties."
As for concerns about respiratory depression after narcotics arestarted, the physiologic data are very clear, he said. "Yes,the respiratory rate drops, but patients compensate by takingdeep breaths and increasing their respiratory volume. In general,this is not a problem."
To use narcotic analgesics effectively, it is important to understandthe difference between dependence, addiction, and pseudo-addiction,Dr. Blum said in his talk (see story above).
Dependence is not addiction, he said. "By dependence we meana physiologic dependence. This is a common problem. People canbe weaned off narcotics very readily." Addiction, he said,is a psychiatric diagnosis, and addiction associated with useof narcotics for medical use is rare.
A more important problem is pseudo-addiction. "We've allhad patients banging on the door saying, I want my narcotics,now!" Is this addiction? No, Dr. Blum says. "It's aconsequence of inadequate pain control, and it's really our fault,the system's fault."