Concerning the oral route of analgesia in cancer pain.
Interview with Eric Chevlen, M.D
 Dr. Eric M. Chevlen received his M.D. from Ohio State University in 1974. His internship was at Case Western Reserve University Affiliated Hospitals, and his residency was at Mt. Sinai Hospital in Cleveland. Dr. Chevlen served his oncology fellowship at the National Cancer Institute 1976-1978, and his Hematology Fellowship at the University of California at San Francisco, Cancer Research Institute. He is one of the few physicians in America to be certified by five specialty boards: the American Board of Internal Medicine, the American Board of Medical Oncology, the American Board of Hematology, the American Board of Pain Medicine, and the American Board of Hospice and Palliative Medicine. Dr. Chevlen specializes in the treatment cancer and pain. He also serves as the Director of Palliative Care at St. Elizabeth Health Center, and is a hospice medical director. Dr. Chevlen is also an educator and researcher. He is currently an Assistant Professor of Internal Medicine at Northeast Ohio Universities College of Medicine, and he lectures widely on pain and palliative care. His current area of research interest is opioid analgesia. He currently practices medicine in Youngstown, Ohio, where he lives with his wife, Laurel, and their two sets of twins.
Pain.com: Why is the question of routes of administration important in the treatment of cancer pain?
Dr. Chevlen: Patients with cancer pain are more likely than patients with chronic non-malignant pain to have comorbidities that impact on drug delivery. Also, the patient with cancer pain usually has a pain problem that changes more rapidly and more frequently than does the patient with non-malignant pain.
Pain.com: Can you give me some examples of situations that impact on drug delivery?
Dr. Chevlen: The most obvious one, of course, is the inability to swallow. But there are others. Hectic fevers and cachexia can have a major adverse impact on the reliable delivery of fentanyl by the transdermal route. Hospice patients dying at home may have no venous access. Open wounds and extensive soiling of the skin due to incontinence may preclude subcutaneous drug delivery.
Pain.com: Is there any one best route of delivery?
Dr. Chevlen: I agree with the recommendations of the Agency for Health Care Policy and Research, and with the World Health Organization: for most patients, for the greater part of their illness, the oral route is preferred.
Pain.com: Why is that?
Dr. Chevlen: There is a large number of agents, both opioid and non-opioid, available by that route. The large surface area of the stomach and small intestines provide a huge area for absorption. The oral route, of course, is cheap, low-tech, and almost always available.
Pain.com: Is there any role for spinal therapy in cancer patients?
Dr. Chevlen: I can't say there is no role, but it certainly is a limited one. Most patients can benefit from oral opioids, and the therapeutic index is broad enough for most of them to allow this simpler and more reliable route for therapy. The key to making oral therapy successful, and thereby avoiding invasive therapies such as epidural or intraspinal drug delivery, is assiduous attention to management of side effects.
Pain.com: How is that done?
Dr. Chevlen: The first side effect that must be addressed is sedation. Most patients who start opioids experience transient sedation. Proactive management is key to successful therapy. The patient should be told to expect sedation, and to expect it to be transient. Many patients enter opioid therapy fearful that they must "become zombies" in order to achieve adequate analgesia. They should be reminded that a person in pain sleeps poorly, and that when the pain is relieved they will feel drowsy as they get caught up on lost sleep. After a few days, they should expect their wakefulness to improve.
Pain.com: What if it doesn't?
Dr. Chevlen: Patients who have ongoing sedation may benefit from methlyphenidate or other stimulants. This will allow them to be wakeful at doses of opioids necessary to maintain good pain control.
Pain.com: What other side effects need to be managed to allow successful use of the oral route?
Dr. Chevlen: Nausea is not uncommon during the first few days of opioid therapy, or after a dose escalation. Forewarning the patient of this possibility will reduce the likelihood of the patient's rejecting the therapy on the basis of a side effect that will ultimately prove to be transient. Opioid-induced nausea is usually mild. For more severe or protracted nausea, it is wise to add a phenothiazine antiemetic, such as prochlorperazine or promethazine. When these simple agents are not sufficient, the patient may benefit from 5HT3 antagonists, such as ondansetron, granisetron, or dolasetron. Finally, there are reports of the antipsychotic agent olanzapine being dramatically effective for this indication.
Pain.com: Does constipation ever preclude oral therapy?
Dr. Chevlen: Occasionally. Most opioid-induced constipation can be prevented by early use of cathartic agents, such as senna or lactulose. It is important to note that mere stool softeners, such as docusate, are less likely to be effective. As Dr. Arthur Lipman says, "stool softeners give you mush without push." For those rare patients for whom constipation remains intractable or a dose-limiting side effect, there may be a benefit in switching to transdermal fentanyl.
Pain.com: What is the role of the parenteral route in relieving cancer pain?
Dr. Chevlen: Patients who are hospitalized and receiving other IV therapy are reasonable candidates for intravenous analgesia if the oral route is compromised. Similarly, homebound cancer patients receiving intravenous hyperalimentation or other intravenous therapy may easily receive their opioid analgesic by the same route; it adds no major burden then. However, there is little reason to establish an IV line just to deliver an opioid analgesic. Subcutaneous delivery works as well, with far less difficulty in maintaining parenteral access.
Pain.com: What is the role for spinal therapy in cancer pain?
Dr. Chevlen: Because of its cost, invasiveness, and risk, it is the route of last resort. But there are clearly patients who do not do well with drug delivery by other routes, usually due to dose-limiting side effects, who do better with spinal therapy.
Pain.com: Which is the preferred route, intrathecal or epidural?
Dr. Chevlen: Each has its advantages and disadvantages. The epidural route has fewer complications when the likely duration of therapy is brief, that is a few weeks. But the intraspinal (intrathecal) route is probably better when the therapy is likely to be needed for much longer periods of time.
Pain.com: Are there any other routes of delivery worth discussing?
Dr. Chevlen: Briefly, yes. In homebound hospice patients, sublingual application of high concentration oral morphine solution can allow ongoing analgesia and prevention of withdrawal during the last days of life, when the patient is often unable to swallow. Also, there are reports of sustained-release opioids being given rectally or even vaginally for that same purpose. Transbuccal administration of fentanyl gives very rapid onset of analgesia, and may be the drug of choice for predictable incident pain, such as that associated with dressing changes, or walking to a commode.
Pain.com: Any final comments?
Dr. Chevlen: Yes. We've been talking about routes of administration. But we must keep in mind that the route of administration is just a means toward an end. That end is pain relief in the cancer patient. We now have enough drugs and enough available routes of administration, so that no cancer patient should have to fear living or dying in pain. If cancer pain were untreatable, that would be a tragedy. That it is treatable, but is so often undertreated is not a tragedy, but a scandal. It is our duty to use the wide range of available drugs and routes of administration to allow our patients to live and die in comfort and dignity.
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