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Article Excerpt
ABSTRACT: Opioid analgesics provide effective treatment for non-cancer pain, but many physicians have concerns about adverse effects, tolerance, and addiction. Misuse of these drugs is prominent in patients with chronic pain. Recognition and early prevention of misuse helps physicians identify the causes and proceed with patient care. Most persons with chronic pain have a significant medical comorbidity (eg, asthma) that affects treatment decisions. All patients should undergo an initial comprehensive evaluation. Patients often have a psychiatric comorbidity, such as depression or anxiety. There is no gold standard for risk assessment, but several traditional measures may be used. Pain medicine practitioners increasingly are using urine drug screens to monitor adherence to long-term opioid therapy. Controlled substance agreements help improve patient compliance.
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Chronic pain is a costly problem that influences every aspect of a person's quality of life, interfering significantly with sleep, employment, social functioning, and activities of daily living. Patients often report depression, anxiety, irritability, sexual dysfunction, and decreased energy. Family roles are altered, and worries about financial limitations and the consequences of a restricted lifestyle abound. (1-5)
Epidemiological studies have independently documented that chronic pain is seen as an immense problem worldwide. (6-8) Symptoms affect more than 90 million Americans--about one-third of the US population. Chronic pain accounts for 21% of emergency department visits and 25% of annual missed workdays. Including both direct and indirect costs, chronic pain is responsible for up to $100 billion in annual costs, imposing the greatest economic burden of any condition. (9-12)
Several studies have confirmed that opioid analgesics are useful for managing acute and cancer-related pain. (13) They also are considered effective treatment for persons with chronic noncancer pain and are known to have a similar safety advantage to that of long-term therapy with NSAIDs. However, many physicians are reluctant to support the use of opioids in these patients because they have concerns about adverse effects, tolerance, and addiction.
Epidemiological data from the National Comorbidity Survey of Psychiatric Disorders in the United States indicate a lifetime prevalence of 7.5% for drug dependence (illicit or prescription drugs) and 14.1% for alcohol dependence. (14) About 3% of Americans 18 years or older meet the criteria for illicit drug abuse or dependence as defined by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). (15) In a sample of 363 hospitalized patients, 21.8% had a current addiction to alcohol or illicit drugs. (16)
Prescription opioid analgesics are said to be the most frequently abused drugs in the United States, and misuse is prominent in patients with chronic pain. In a literature review, Strain17 reported that 15% to 23% of patients with chronic pain met the criteria for a substance abuse disorder.
Recognition and early prevention of substance misuse helps physicians treating patients with chronic pain identify the causes and sources and proceed with legitimate medical practice and patient care. (18) Assessment and treatment protocols are needed to determine the potential for abuse when opioids are prescribed and to manage any misuse behaviors. These protocols provide physicians with a better understanding of the patient's background and behavior and help patients who show signs of medication misuse remain compliant when taking opioids for pain.
In this article, we discuss the opioid abuse and misuse issues that often arise in the treatment of patients with chronic noncancer pain and describe assessment and treatment strategies. A case report is offered to illustrate the key points (see the Box, "Case study: At risk for medication misuse," below.
Definition of terms
Concise definitions of terms help clarify the objectives of therapy with opioid analgesics (Table 1). Addiction traditionally has incorporated both physical dependence (becoming dependent on the medication and manifesting withdrawal symptoms when it is discontinued or drastically reduced) and tolerance (the need for increasing doses over time to maintain effect). More recently, it has become clear that physical dependence and tolerance are common in the use of opioids for chronic pain and are unrelated to true addiction. In this context, addiction is a behavioral pattern of substance abuse characterized by overwhelming involvement with the use of a drug. (15, 19) This definition focuses on compulsive use of the drug that results in physical, psychological, and social harm to the user, who continues despite this harm.
Some authors have argued that the traditional definitions are not necessarily appropriate for patients with pain who are taking opioids. (20) Tolerance develops in most patients who receive long-term opioid therapy; if under-medicated, they may demonstrate drug-seeking behaviors or engage in unauthorized dosage increases. In these cases, the drug-seeking or other seemingly addictive behavior, or pseudoaddiction, disappears when an adequate analgesic dosage is reached. (21)
Some patients may become psychologically dependent after long-term opioid use. (22, 23) Others, who continue to receive extremely high doses of opioids long term, manifest impaired cognition and psychomotor performance and hyperalgesia and only show improvements in pain and neuropsychological functioning after detoxification. (24) The literature points to a relationship between early misuse and addiction, which lends more support to the need for early detection and intervention.
Medical comorbidity
Most persons with chronic pain have significant medical comorbidities that affect treatment decisions. Patients often report having asthma; chronic obstructive pulmonary disease; diabetes mellitus (DM); coronary artery disease; hypertension; ulcers; kidney, bladder, and liver problems; or a history of cancer. Comorbid conditions may contribute directly to the pain complaint (eg, DM, cancer, war wounds) or may be unrelated.
Persons with chronic pain often smoke cigarettes, gain weight,...
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