Evaluation for Opioid Management: Opioid Misuse Assessment Tools and Drug Testing in Pain Management

Key Points

• Chronic pain inflicts an enormous human toll of suffering and disability and is often associated with psychiatric comorbidities such as emotional distress, negative affect, depression, and anxiety.

• There is a corresponding relationship between mood disorder and opioid misuse, abuse, and/or diversion.

• Because of suboptimal opioid prescribing practices in the past, there has been an opioid epidemic, and the future of opioid prescribing calls for careful monitoring and risk assessment.

• There are several validated and reliable self-report screenings that can help to assess the risk of opioid misuse.

• Opioid therapy agreements, urine toxicology screens, the use of PDMPs, and behavioral interventions are designed to improve opioid compliance.

Background and Overview of Pain Issues

Chronic pain, defined typically as pain lasting longer than three months, is a global problem that can negatively impact every facet of daily living. ^, It is estimated that in the United States, there are between 50 and 100 million adults with chronic pain, affecting more individuals than heart disease, diabetes, and cancer combined. Chronic pain contributes to psychological distress, social isolation, sleep disturbances, and job loss and is the major reason people visit their primary care physicians. Chronic pain is known to interfere with routine daily activities and negatively affect appetite, mood, energy level, and sexual activity. Persons with chronic pain often have recurrent worried thoughts about finances, family interactions, and future disability. It is estimated that chronic pain costs up to $635 billion annually in healthcare expenses and lost productivity in the United States alone-more than any other chronic disease. Treatment for chronic pain is three times more expensive than treatment for similar conditions without chronic pain. The burden caused by chronic pain is escalating because of the increasing average age and associated medical comorbidities that come with living longer. Chronic pain represents a significant public health challenge because of the lack of adequate assessment and treatment and noted disparities in the experience of pain among population subgroups.

Opioids are known to be useful in the treatment of acute and cancer-related pain. It is estimated that between 5 and 8 million Americans use opioids for the management of chronic non-cancer pain. More recently, providers have become reluctant to prescribe opioids for the treatment of chronic non-cancer pain because of concerns regarding tolerance, dependence, and addiction, as well as uncertainty about their long term benefit in this setting. There has been a dramatic increase in opioid-related deaths, and significant media attention to concerns of addiction predominately from prescription opioid use, resulting in what has been known as the “opioid crisis.” ^, This crisis was attributed, in part, to the steady increase in the use of prescription opioids in the United States, ^, that was seen as the main contributing factor to the increased incidence of prescription opioid abuse, and opioid-related overdoses and hospitalizations. ^, In the United States, prescription opioids are responsible for more deaths than cocaine and heroin combined and are known as the most abused drug class. ^, Although this percentage has been gradually decreasing, for a time the United States consumed an estimated 80% of all prescription opioids worldwide. Persons who abused prescription opioids in the past believed that they were safer and more accessible than street drugs, often available as left-over medication from family and friends, and perceived to be pure because of increased regulations on the manufacturing of prescription drugs. Many providers who manage patients with chronic pain have limited training in the assessment and treatment of pain. They are unaware of risk assessment strategies and methods for close monitoring of persons receiving prescription opioids. Studies have shown that those at risk of misusing opioids tend to be the ones most likely to be prescribed opioids for pain.

In this chapter, we present definitions of terms related to opioid misuse and abuse and share information on the prevalence of prescription opioid misuse. We will give an overview of risk factors and risk assessment strategies designed to improve opioid compliance. Last, we will briefly discuss behavioral interventions designed to improve and maximize compliance and explore future considerations for improving patient engagement.

Terminology

It is important to have a clear understanding of the terms used to describe the problem of prescription opioid abuse. Often abuse is used to describe non-medical use, misuse, and/or addiction. Therefore it is important to first define the terms used to describe this multidimensional problem. The definitions used in this chapter are presented in Table 51.1 . For the purpose of this chapter, we define abuse as any repeated use of an illegal drug or the intentional self-administration of a medication for the express purpose of altering one’s state of consciousness and achieving euphoria (such as getting high). ^, In contrast, misuse is the use of any drug in a manner other than indicated or prescribed, but not necessarily with unlawful intent. For example, a patient may split a pill to reduce the dose or double-up on the dose for added pain relief. In contrast, addiction is a primary, chronic, neurobiologic syndrome characterized by behaviors that include impaired control over drug use, compulsive use (that may interfere with function and performance of regular duties), craving, and continued use despite harm. Addiction refers to a behavioral pattern of substance abuse characterized by overwhelming involvement with the use of a drug. The compulsive use of the drug results in physical, psychological, and social harm to the user, and use continues despite this harm. Iatrogenic addiction is an addiction that results from exposure to opioids for acute pain.

Aberrant drug-related behaviors are any behaviors that suggest the potential presence of substance abuse or addiction (e.g. “doctor shopping”). ^, Pseudoaddiction has been a term used to describe behavior that was thought to reflect addiction but which disappeared after suitable amounts of medication was given for the treatment of pain. For example, it was thought that any patient with undertreated pain, due perhaps to the provider’s fear of addiction or abuse, who sought care from another physician for the purpose of adequately relieving pain might have had signs of pseudoaddiction. It is uncertain whether this condition exists and was used in the past to support the increased use of opioids. However, this term has recently gone out of fashion.

Physical dependence is a condition of physiologic withdrawal after the dose of many medications, including an opioid, is rapidly reduced. Withdrawal symptoms are generally specific for the class of substance involved, e.g. opioids, and benzodiazepines. This is noted to occur among all mammals who have been administered opioids over time. After a rapid dose reduction, including decreased blood levels of an opioid and/or administration of an antagonist, signs of withdrawal may include diarrhea, rhinorrhea, piloerection, insomnia, irritability, and psychomotor agitation. ^, The effects of opioid withdrawal can be reduced by gradually tapering the dose downward over an extended period. Physical dependence is a common condition of anyone actively using opioid therapy on a chronic basis and is not considered an addiction. Tolerance is another phenomenon associated with the long term use of opioids, where there is a need for increasing doses to obtain the same effect. ^{, ,}

Diversion has been defined by the Drug Enforcement Administration as a redirection of a controlled substance for use in an unlawful manner. Drugs can be diverted by being stolen or being sold on the street. Additionally, it includes obtaining the medication from a legitimate source for legitimate means but used for an illegal purpose such as selling the drug to get high. Among adults 50 years and older, the main source of receiving opioids is through a physician’s prescription, with this age group making up 25% of the individuals who self-reported opioid misuse. For individuals under 50 years old, it is more commonly reported that opioids were obtained from an illegal source.

Prevalence of Prescription Opioid Misuse and Addiction

Addiction is generally understood to be a chronic condition from which recovery is possible. However, the underlying neurobiologic dysfunction, once manifested, is believed to persist. ^, Therefore the prescription of opioid analgesics to a patient with a predisposition for or history of addiction could initiate an addictive disorder or relapse. Some of the disparity between the results of studies reporting an extremely low risk of addiction for hospitalized patients and the high proportion of substance abuse in the general population can be explained by the unreliable methodology of existing surveys of iatrogenic addiction (e.g. addiction as a result of exposure to opioids for acute pain) in hospitalized patients.

Although there has been a lack of high-quality evidence or consistent findings on the prevalence of substance abuse among persons with chronic pain, there is a trend to suggest that escalating doses of opioids among those with chronic non-cancer pain is associated with increased risks of substance use disorder and opioid-related adverse outcomes. Rates of opioid misuse and addiction among persons with chronic pain have been varied and were thought to be much higher than initially published in the 1980s. ^{, ,} One reason given for the variable rates of addiction was because they were not obtained from representative chronic pain patients, and vague definitions of addiction were used. The studies in question examined the retrospective prevalence of cases rather than the incidence and onset of new cases of addiction. ^, Additionally, those perceived to have mental health issues or substance abuse problems were often excluded. Patients with chronic pain often present with a mood disorder and a comorbid psychiatric condition, and they are likely to be prescribed opioids. Thus it has been assumed that early rates of prescription opioid abuse were low. Unfortunately, there are limited large-scale studies designed to determine reliable rates of addiction among individuals treated for chronic pain. A systematic review and meta-analysis of the incidence of iatrogenic opioid dependence and abuse revealed a pooled incidence of 4.7%. The authors found that when diagnostic and statistical manual of mental disorders (DSM) criteria were used, the rates of addiction were higher (11.3%) than when using ICD-9 criteria (1.3%). Vowles et al. found wide variability in prescription opioid addiction rates across studies (i.e. range: 8%–34.1%). The differences observed in opioid addiction rates are assumed to be due, in part, to differences in study populations, study designs, and settings in which opioids were prescribed. Unfortunately, when addiction is based on DSM-V criteria (opioid use disorder), the reported addiction rates tend to be much higher.

Prescription Opioid Misuse Risk Factors

Guidelines from the Centers for Disease Control (CDC) recommend that healthcare providers make every effort to identify abuse and possible diversion of prescription opioids. ^, The guidelines suggest that particular problematic behavior, such as seeking prescriptions from multiple providers, using illicit drugs, selling or diverting medications, snorting or injecting medications, and using drugs in a manner other than the way they were intended, should be carefully monitored. Despite the need to identify misuse of opioids and limit inappropriate prescribing, healthcare professionals need to provide appropriate pain relief for individuals who have evidence of genuine pain problems.

Additional problems associated with chronic use of opioids include psychological dependence, ^, impaired cognition, problems with psychomotor function, and possible development of opioid-induced hyperalgesia (OIH). ^, High-dose opioids, which some define as greater than 180 mg morphine equivalent a day, have been known to lead to sleep apnea, respiratory depression, and disordered breathing. Of most concern is the risk that greater dependence on opioids can lead to addiction. ^, This strongly supports the need for risk assessment at the point of opioid initiation and for continued careful monitoring, ^{, ,} maintaining lower doses of opioids when indicated, ^{, ,} tracking compliance, ^{, ,} and offering an interdisciplinary approach to pain management. ^,

There are identifiable characteristics of those individuals who are at lower risk of misusing opioids. In particular, those who are older, who present with stable mood, have a record of being reliable in keeping appointments and in following medical recommendations, who have no history of overusing medications, who have no cognitive deficits, and who are generally pleasant are at lower risk of opioid misuse. ^, Equally, there are characteristics of those who are at higher risk of medication misuse. These include those who are younger and have a history of risk-taking behavior, who have a history of legal problems, who are in frequent contact with others who misuse substances, who have a mood disorder, and who have a personal or family history of substance abuse. Additional factors include previous drug or alcohol rehabilitation, history of early childhood abuse and trauma, multiple stressors, smoking cigarettes, or regularly using other substances that lead to dependence ( Table 51.2 ).

An important reminder to anyone prescribed opioids for chronic pain is that they ultimately are the ones who must manage the opioids in a responsible manner, and they need to be vigilant about factors that may contribute to opioid abuse. It is important to remind anyone using prescription opioids for pain of factors that may increase their susceptibility of encountering problems. These factors may include impulsivity, ^, predispositions to self-medicate symptoms of anxiety or depression, ^, and experiencing drug liking or craving of the medications. ^,