Summary by Noam Koenigsberg, MD
98
Based on “Principles of Addiction Medicine” Chapter by Edward C. Covington, MD, and Margaret M. Kotz, DO
INTRODUCTION
Clinicians have a hard time distinguishing between pain patients and addicts. In fact, each condition increases vulnerability to the other, obscures the diagnosis of the other, and impedes treatment of the other. It is for this reason that a chapter on comorbid pain and addiction is necessary.
SIGNIFICANCE
A growing number of patients seeking treatment for substance use disorders (SUDs) are addicted to prescription opioids, and a large number suffer from comorbid chronic noncancer pain (CNCP). Estimates of the prevalence vary widely based on the methodology used in studies, inadequate investigations, and inappropriate definitions of addiction. Fishbain et al. reviewed 24 studies, and the range of CNCP patients that had comorbid SUDs ranged from 3.2% to 19%. In a subsequent review of studies, of those with no prior SUD that were exposed to therapeutic opioids, only 0.19% developed an SUD. Cicero et al. found that in 1,408 patients in treatment for opioid use disorder, 80% had initiated opioid through a prescription but most had a prior SUD and had an average of three prior treatments for substance use. It appears, that US physicians aren’t creating addiction but inadvertently (one hopes) prescribing opioids to people with preexisting SUDs.
EPIDEMIC OF PRESCRIPTION OPIOID ABUSE
There has been a dramatic increase in prescription opioid–related drug misuse, addiction, and deaths concurrent with a dramatic rise in prescription opioids for chronic pain. Greater quantities of opioids are available for therapeutic use, and therefore, more are available to divert and misuse. Furthermore, people at risk of misuse are more likely to be prescribed opioids. This can be countered by a multidimensional approach to pain management and improving prescribing practices that reduces prescribing opioids to candidates who potentially will abuse the opioids.
PROBLEMS OF COMORBIDITY—RECIPROCAL VULNERABILITY
Data suggest that people suffering from addiction are susceptible to chronic pain and pain increases vulnerability to addiction. Chronic pain and addiction share several risk factors including childhood and adult trauma and posttraumatic stress disorder.
Diagnostic Confounds
Addiction can complicate the diagnosis of pain as it provides incentive to maximize complaints of pain and minimize benefits of treatment. Pain also complicates the diagnosis of addiction as patients may not demonstrate the typical diagnostic clues seen in addiction such as engaging in illegal activities or having complications such as infections from drug use. Furthermore, patients might not feel they are addicted as they attribute their use to treating the pain.
Treatment Impediments
It is more difficult to treat CNCP in the presence of addiction. It can be hard to find the correct dose as patients may want to continue upward titration indefinitely, which can leave patients on massive doses of opioids with poor functioning. It can also affect the therapeutic relationship where the prescriber suspects drug-seeking behaviors and the patient might have unrealistic expectations of relief of pain.
Diagnosis of Addiction in CNCP
The criteria for diagnosis of addiction in patients with CNCP are similar to those without pain. The DSM-5 uses the new term “opioid use disorder” (please see DSM-5 for actual criteria). The indicators for therapeutic opioid addiction are more subtle than with recreational addiction. Loss of control can manifest with an inability to ration one’s pain meds, craving can be one’s refusal to discuss any other treatment besides opioid treatment, and use despite adverse consequences might manifest in family reports rather than legal trouble. Multisourcing is a common problem, which can be identified by reviewing state electronic prescription drug monitoring databases.
RED FLAGS FOR ADDICTION— PSEUDOADDICTION
Pseudoaddiction describes behaviors that mimic addictive behavior but result from inadequate analgesia rather than addiction, and the addictive behavior improves when the pain is controlled. The difference between pseudoaddiction and addiction can be very hard to differentiate and is often made in retrospect.
Screening
The best predictor of future substance use is past substance use. At a minimum, a thorough substance abuse history should be taken including looking for history of opioid use disorders and other substances.
Screening Tools/Prediction
A number of instruments are available to screen for the presence of SUDs including CAGE inventory, Prescription Drug Use Questionnaire, and Drug Abuse Screening Test. Many instruments seem to detect preexisting SUDs, which can help predict the probability of future aberrant behavior. Some of these include the Opioid Risk Tool and the Screener and Opioid Assessment for Patients with Pain.
Iatrogenic Addiction in CNCP
Government studies of sources of nonmedical opioids show that less than one fifth of abusers received a legitimate prescription from a physician. The understanding of addiction is that it is a consequence of neuroplasticity in the brain, which is contingent on a prolonged period of frequent or continued exposure to substances. Therefore, the risk of addiction could be proportional to the dose and duration of treatment. Triggering relapse is far easier than inducing addiction. Clinicians need to identify those at highest risk for developing opioid use disorders, which include the young and those with a prior SUD or comorbid mental disorder, and to institute practices that minimize the likelihood of diversion.
TREATING PAIN IN THE PRESENCE OF ADDICTION—ACUTE PAIN
Patients actively using opioids are frequently under medicated for their acute pain as physicians fail to account for the presence of tolerance or fear contributing to their addiction. The addicted patient is likely to benefit from multimodal analgesia thereby reducing the need to rely solely on opioids.
Acute or Chronic Pain
Many of these patients are on chronic high-dose opioids for pain and are under medicated due to providers’ failure to realize that these patients will likely require higher doses of analgesics for their acute pain. Even when proper attention is paid to these issues, it is much more difficult to achieve satisfactory analgesia in the highly tolerant patient.
Patients in Medication-Assisted Recovery
Those in methadone maintenance treatment will receive no analgesic effect from their regular methadone dose and will need that dose on top of greater than usual doses of opioid analgesics for adequate pain control. Buprenorphine is a strong partial agonist and will displace other opioids and cause a withdrawal syndrome, so clinicians need to avoid giving buprenorphine to patients currently on opioids.
Frequent Emergency Department Visits
In 2006, it was reported that 39% of encounters in which opioids were given or prescribed were through an ER. Some states have come up with guidelines to control the use of opioids such as not giving opioids for chronic pain in the ER, not refilling lost or stolen scripts, avoiding IV opioids, and coming up with an outpatient plan for patients who frequent the ER.
CNCP
Nonpharmacologic treatments for CNCP include physical therapy (PT), exercise, fitness, and yoga. Interdisciplinary pain rehabilitation programs have shown the best outcomes in studies. Unfortunately, there is about one of these programs for every 670,000 patients with chronic pain. Other techniques include regional anesthesia and neuroaugmentation. Nonopioid pharmacologic agents include gabapentinoids, antiepileptics, Selective norepinephrine reuptake inhibitors (SNRIs) tricyclic antidepressants, capsaicin, transdermal lidocaine, Tylenol, and NSAIDs. Patients with active addiction should receive chronic opioid therapy only if there are clear indications for it and they are in active treatment for their addiction. The safest treatment for people with comorbid SUDs and CNCP is to avoid opioids if clinically possible.
Choice of Opioid and Route of Administration
Mironer et al. compared the frequency of prescriptions of various opioids with the frequency of abuse to generate a ratio reflecting risk of misuse. Their results were (starting with highest risk of abuse) Stadol NS (4.4), propoxyphene (2.5), hydrocodone (1.61), codeine with Tylenol (1.45), oxycodone (1.35), OxyContin, (0.73), MS Contin (0.66), fentanyl patch (0.230), and methadone (0.08). It appears some opioids are more abused than others, and perhaps, transdermal and extended release formulations are less abusable. Methadone has been established to be both efficacious for opioid addiction and pain. Due to its potential to accumulate and result in overdose, it is a medication that needs to be given by clinician who is experienced and knowledgeable about the medication and can closely monitor the patient. Buprenorphine, although only approved for addiction, is an excellent analgesic and can be used off-label to treat pain and addiction simultaneously. Advantages include less risk of overdose and respiratory suppression, and when combined with naloxone (Suboxone), it is less likely to be diverted.
Additional Rewarding Medications
Patients suffering with addiction and/or CNCP are likely to have comorbid psychiatric illnesses and more likely to be treated with sedatives, which are commonly abused. The risks of combining opioids with sedatives that augment opioid toxicity and have abuse potential seem unjustified given that there are alternatives to sedatives that can be used. Alternatives include antidepressants and antiepileptic drugs.
AGONIST OR ABSTINENCE?
Abstinence-based treatment has a high failure rate; therefore, medication-assisted treatment is recommended for most.
CONCLUSION
In order for treatment of comorbid pain and addiction to be successful, the provider has to ensure that both pain and addiction are addressed. Too often, pain specialists ignore addiction, and addiction specialists fail to ensure that the pain is being evaluated and treated. On a positive note, when treated properly, patients with pain and addiction comorbidity can have excellent outcomes.
KEY POINTS
1. A growing number of patients seeking treatment for SUDs suffer from chronic pain and are addicted to opioids.
2. People suffering from addiction are susceptible to chronic pain, and pain increases the vulnerability to addiction.
3. Screening is a necessity as the best predictor of future substance abuse is past substance abuse.
4. When choosing treatment, keep in mind nonpharmacologic and nonopioid options, and when choosing an opioid, the choice of opioid and route of administration makes a difference in terms of potential of abuse.
5. Treatment can be successful if the practitioner addresses both pain and addiction.
REVIEW QUESTIONS
1. There has been a dramatic increase in prescription opioid–related drug misuse and addiction because:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
