Jennifer P. Schneider, M.D., Ph.D.
Pain Practitioner, Winter 2006-2007, 16:17-24.
Although chronic pain is the most frequent cause of suffering and
disability that seriously impairs the quality of life in the
Such responses bespeak a fundamental misunderstanding of chronic pain and of opioids. This article will address these misunderstandings. Its focus is on opioids, but keep in mind that treating chronic pain often requires a comprehensive approach including several non-opioid medications (NSAIDs, (acetaminophen, NSAIDs, anticonvulsants for neuropathic pain, muscle relaxants for muscle spasm, etc.) along with physical therapy, exercise, injections, and alternative approaches.
Chronic pain is e pain that lasts 3 or 6 months (or some other arbitrary time period) and which has lost its usefulness. Acute pain in a particular body part is a useful signal that something has gone wrong and needs assessment, but with chronic pain there is often a disconnect between the source of the pain and the pain experience. The cause of the pain may have resolved, or the painful body part may even have been amputated. But the pain is still real. When acute pain is prolonged (e.g. by undertreatment), changes occur in the central nervous system (a phenomenon called central sensitization) such that the pain signals continue to be sent through nerve fibers to the brain, no matter what is going on at the original site of the pain (Woolf 2000). The pain signals have taken on a life of their own, much like an experienced typist who starts typing a word and finds his or her fingers completing a commonly typed word rather than the one intended, or a driver who intends to drive home by a different route than normal, but finds himself having unthinkingly turned the car to the street he usually uses. In chronic pain patients, nerve signals that are normally interpreted as heat or pressure may be perceived as pain (allodynia), or normally mild pain signals may be severely painful (hyperalgesia).
The result is that it is hard to assess chronic pain objectively. Typically what is observed is pain behavior, so that the patient who grimaces and groans, whose face is pale, who is hyperventilating or crying, is believed to be in a lot of pain, whereas a patient who sits quietly, or who is observed laughing in the waiting room, is thought not to be in pain. Chronic pain patients, however, adjust to their condition, as does their autonomic nervous system. In reality, the best measure of chronic pain intensity is the patient’s word. This is considered by JACHHO (Joint Commission on Accreditation of Health Care Organizations) the gold standard of pain assessment (JCAHO, 2000). Not believing the patient is likely to lead to exaggerated pain behaviors and can damage the practitioner-patient relationship.
The goal of acute pain treatment is first and foremost to diagnose and treat the source of the pain, and second to provide pain relief. Chronic pain treatment, however, is different. The initial step again is diagnosis and definitive treatment. But once the patient is beyond that stage – the back pain has been operated twice and the surgeon now says that additional surgery is unwarranted; the neurologist says the headaches are not due to a brain tumor but rather are a chronic recurrent problem; the patient has been patched up after the car accident but pain remains – the goals now become relieving pain and improving function. Patients often believe that if only one more sophisticated test is done or specialist seen, the “real cause” can be determined and curative treatment instituted. Most of the time, this is not so; patients need to be educated to take the focus off diagnosis and on to improving their function. A successful outcome in chronic pain treatment is one that improves the patient’s functioning. When a patient says, “I have my life back,” he doesn’t mean that he is still spending all day in bed, but with less pain. He means he can now go to work, walk the dog, clean the house, do yardwork, have sex, etc. That constitutes a good outcome, but getting there may require strong pain medications.
In their position paper on pain management for geriatric patients, the American Geriatrics Society wrote that opioids are safer than NSAIDs. (AGS, 2002) Unlike NSAIDs, opioids do not cause GI bleeding, don’t elevate blood pressure, and have no specific organ toxicity. Their chief side effects are nausea/vomiting, sedation/respiratory depression, and constipation. The first two usually resolve with continued dosing. Constipation does not, so that patients on opioids need a continual bowel program. Opioids bind to mu receptors in the gut, slowing down the transit of materials through the intestinal tract. For this reason, fluids and fiber aren’t sufficient; the patient needs a laxative to counteract the slowing effect of the opioid. I generally recommend a preventive regimen of daily senna plus a stool softener. Chronic opioid administration often causes a subnormal testosterone level in males. (Daniell, 2002; Rajagopal et al, 2003.) This can result not only in decreased libido and erectile dysfunction but also in decreased muscle strength, less energy, and eventually in osteoporosis. All male patients on chronic opioids should have their testosterone levels checked. Unless contraindicated, consider testosterone replacement.
There is no accepted upper limit of safety for opioid analgesics. Because of genetic differences and varying pathology, patients differ enormously in the dose needed for adequate analgesia. Patients may also differ genetically in their response to a particular opioid (Galer et al, 1992), so if high doses of one opioid are not effective, consider changing to another. Opioid-induced sedation typically resolves with a few days after a dose is begun or increased, so patients need to avoid driving when sedated. Once they feel alert, generally it is safe to drive because they have adequate psychomotor functioning (Jamison t al, 2003; sabatowski et al, 2002, Fishbain et al, 2002).
Tolerance is the need to increase the dose to get the same effect, or a decrease in effect when the same dose is continued. Asking “Do patients get tolerant to opioids?” is asking the wrong question. The correct response is, “Tolerant to which effect?” Opioids have several effects, and tolerance to these differs. As mentioned above, tolerance to sedation and nausea is common, a desirable outcome. Tolerance to constipation is not, which is why an ongoing bowel program is necessary. Contrary to common opinion, tolerance to the pain-relieving effect of opioids is uncommon. (Scimeca et al, 2000; Portenoy RK, 1996) Research in animal studies suggests that in some situations opioids cause hyperalgesia (Mercadante S et al, 2003) but this is rarely observed in the clinical setting. Usually when a patient is on a dose of opioid that gives good pain relief, he or she is likely to stay on that same dose for a long time. When the patient complains of increased pain, consider the following possible reasons:
Increased pain after a year of two of a stable dose is not due to late development of tolerance. Assessment requires going back to basics: re-evaluate the back or whatever region of the body has increased pain.
Understanding physical dependence versus addiction.
Physical dependence is a property of various classes of drugs, including opioids and corticosteroids. Once the body has become habituated to such drugs, abrupt cessation results in a recognizable withdrawal syndrome. Full-blown withdrawal from steroids and alcohol is potentially fatal; withdrawal from opioids is uncomfortable but rarely dangerous. Some drugs of abuse are associated with a withdrawal syndrome; others (such as cocaine and marijuana) are not. Withdrawal symptoms can be avoided by tapering the drug, as every practitioner who prescribes corticosteroids knows. Physical dependence is a different phenomenon from addiction. Confusion arises because opioids can produce both physical dependence and addiction. Pain patients treated chronically with opioids often become physically dependent, but only occasionally develop de novo addiction. A prior history of drug or alcohol addiction or abuse increases the risk of addiction.
Drug addiction is a disease in which there are three elements
Signs of possible drug addiction in the medical setting may include:
For a more detailed description of addictive disorders, look at the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV, (APA, 1994), but notice that the word addiction appears nowhere in this “bible” of psychiatric disorders. Instead, the word has been replaced by the term dependency, so that opioid addiction is called opioid dependency, which is not at all the same thing as physical dependency on opioids. This is why when discussing issues of opioid addiction versus physical dependency, it’s crucial to make the distinction.
Surprisingly, there are no solid published studies to
answer how likely prescribing opioids for chronic pain is to engender
iatrogenic addiction. In the
In the clinical setting, undertreated patients may
look like addicts, because in their efforts to obtain more pain relief they may
use more than prescribed, go to more than one prescriber to gain opioids
(“doctor shopping”), or make up stories why they need early refills. Behavior
that results from undertreated pain rather than from addiction is called pseudoaddiction
Patient assessment for a chronic pain problem begins with a history of the pain problem, supplemented by old records of prior assessment and treatment. Let’s assume that a patient who comes to you for pain management has chronic back pain that has been evaluated and treated surgically. She has had several local injections with transient benefit. Assessment begins with obtaining a history of the pain problem, treatments already tried, current medications, and previous medications tried for the pain. Ask about the patient’s life before the back pain began and how the back pain has impacted her functioning. What is she able to do now? What are her goals in seeking pain management? Ask about other current and past medical problems, the patient’s job history and current employment, and whether or not she is living alone. Inquire about past or present use of cigarettes, alcohol, coffee, and illicit drugs. I phrase the latter as, “Have you had any experience with recreational drugs?” A prior addiction or abuse history does not rule out opioid use, but requires caution.
The goal of prescribing pain medications is to maximize the patient’s functioning, not to minimize the dose. With this in mind, the process consists of beginning with a low dose to minimize side effects, then titrate upwards until an effective dose is reached. The initial dose and the particular drug depend on what opioid (if any) the patient is currently taking, what experience they’ve had with various opioids, and what attitudes they have about particular drugs. When patients obtain pain relief, they are likely to increase their level of activity, which in turn means a need for an increased dose of opioid. Once the patient’s level of functioning has stabilized, so does the maintenance dose of medication.
In general, short-acting opioids should not be used as the mainstay of chronic pain treatment. They require repeated dosing during the day, keeping the patient focused on his or her pain; provide up-and-down blood levels which can result in periods of mood alteration alternating with increased pain; do not last long enough at night to provide sustained sleep; and are usually formulated in combination with acetaminophen (sometimes aspirin), which is toxic in high doses. Sustained-release opioids, on the other hand, provide smooth blood levels with sustained pain relief and allow better sleep at night.
The plan is to maintain the patient on an effective dose of a long-acting opioid (methadone) or sustained-release preparation (morphine, oxycodone, or oxymorphone, or transdermal fentanyl), and supplement with a small quantity of an immediate-release preparation for breakthrough pain (hydrocodone in Vicodin, oxycodone in Percocet, etc.) Recognize that chronic pain is not uniform throughout the day or week. At times the patient may have increased pain because of increased physical activity, weather changes, end-of-dose failure, or increased anxiety or depression. (Extensive medical literature supports the finding that pain and depression each worsen the other, and when both are present, both need to be treated.) The patient is told to take the sustained-release opioid on a timed basis, and the immediate-release only as needed.
Patients who take opioid analgesics need to be informed consumers. The practitioner’s responsibility is to educate patients about physical dependence, addiction, constipation, preventing diversion, etc. Patients need to understand what is expected of them. A written opioid agreement, to be signed by the patient, spells out the physician’s expectations of the patient. The patient agrees to assist in obtaining old medical records, to obtain opioids from only one prescriber, to get the prescription filled at only one pharmacy, to make no change in dosage without prior discussion with the physician, to obtain any consultations the physician recommends, not to use illegal drugs, and to agree to urine drug screen. The patient also gives permission to the prescriber to discuss the patient with pharmacists and other relevant practitioners. The patient understands that early refills will not be given (except for a good reason).
Part of appropriate assessment for opioid treatment is to determine the level of structure the patient needs. Anyone who has chronic pain deserves treatment, but some people need more structure than others. If a patient cannot reliably manage their own medications, a plan to do so must be arranged. If a problem becomes evident in the course of treatment, the structure may need to be intensified. Some examples from my practice where opioids were prescribed only when a family member agreed to hold and dispense the medications:
Another situation in which a patient cannot be relied
on to take his opioids responsibly is the person with an active drug
addiction. The only way such a person
can be considered for opioid management is if he or she is receiving ongoing
treatment for the drug or alcohol addiction.
A position paper of the
Chronic pain patients need to be seen fairly often – I see stable patients once every two months, but more often initially or if something changes. At each visit the “4A”s (Passik 2000) are assessed and documented, as is a fifth A, affect – how the patient feels.
An important difference between addicts and pain patients who are benefiting from opioid treatment is that drug use secondary to addiction tends to constrict the person’s life; they are increasing focused on the drug, while the rest of their lift suffers. In contrast, appropriate pain treatment expands the person’s life, and lets them function better in their daily life. Talk with patients about their original goals when they started treatment and how close they are to those goals.
Opioids are the strongest available analgesics, and many patients can benefit from using them. Practitioners who prescribe opioids need to be knowledgeable about these drugs, to believe patients unless there is reason not to, and to strive for a balance between adequate pain treatment and prevention of misuse. An excellent guide to the rational use of opioids in treatment of chronic pain was recently published by Gourlay et al (2005). Guidelines for opioid prescribing can also be obtained from the following websites:
American Pain Society
Federation of State Medical Boards of the
Pain and Policy Studies Group, University of
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Daniell, HW. Hypogonadism in men consuming sustained-action oral opioids. J. Pain 3:377-384, 2002.
Rajagopal A, Vassilopoulou-Sellin R, Palmer JL et al. Hypogonadism and sexual dysfunction in male cancer survivors receiving chronic opioid therapy. Journal Pain Symptom Manage 2003:26:1055-1061.
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