Pain Management in Patients With Opioid Use Disorders

Introduction

A growing epidemic in the United States, opioid use disorder (OUD), defined by the American Psychiatric Association, is a desire to take opioids despite the social and professional consequences that arise because of its chronic use. OUD is both a national and global crisis for countries that prescribe and administer opioids, with a reported 16 million people affected worldwide and 2.1 million people in the United States (Dydyk, Gupta, and Jain, 2022).

An Overview on Opioids

Opioid prescription drugs come from both their natural and synthetic forms. Regardless of whether it has been conjugated to a synthetic form or not, all opioids are related in structure to the natural plant alkaloid, Papaver somniferum (National Institute of Diabetes and Digestive and Kidney Diseases, 2020).

The natural alkaloids are referred to as the opiates of opioids, and those include morphine and codeine. The synthetic derivatives include heroin, fentanyl, hydromorphone, methadone, and buprenorphine. Based on accessibility, pain tolerance, efficacy, and patient allergies, pharmacists and clinicians are able to switch between opioid sub classes to find the most optimal therapy for the patient.

Signs and Symptoms

The chronic and excessive use of opioids has been associated with a wide range of psychosocial effects on the patient. According to the DSM-5 criteria utilized for the Diagnosis of Opioid Use Disorder, some of the symptoms taken into consideration include that opioids are taken in larger amounts or over a longer period of time than intended, there is a persistent desire with unsuccessful efforts to cut down on or control opioid use, and the continued use of opioids despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by opioids.

Two distinct symptoms that are also studied as markers for diagnosis are tolerance and addiction. Tolerance refers to the markedly diminished effect with continued use of the same amount of an opioid used in the past. Addiction is reflected by withdrawal symptoms, through which the lack of the opioid can cause symptoms such as agitation and irritability, tremors, and muscle pain (ASAM).

Etiology

The development of OUD is generally regarded as multifactorial in nature. Social, biological, genetic, and environmental factors all play a role in a patient having a higher susceptibility in being diagnosed with OUD; however, it is important to note that this can affect people from all different educational and socioeconomic backgrounds.

Biologically, it has been found that patients deficient in neurotransmitters, such as dopamine, are more likely to seek external sources of endorphins, such as opioids. Genetically, it has been estimated that there is a 50% heritability to OUD,meaning that patients with first degree relatives with a substance use disorder (SUD) are more likely to develop an OUD.

This is also related to the environment of the patient, in which patients exposed to others using opioids may be more likely to develop SUD. Patients with a history of depression, post-traumatic stress disorder (PTSD), or anxiety are more likely to suffer from substance abuse, as well as patients with histories of childhood trauma and abuse.

There increased interest in studying how pharmacogenomics may also play a role in the development of OUD related to the varied susceptibility of receptor affinity to the 3 different principal receptors for opioids: mu, delta, and kappa. However, there is currently no clear evidence in connecting genotype to an opioid’s effect on patient toxicity, dependence, and tolerability (Dydyk, Gupta, and Jain, 2022).

Treatment/Management

It is crucial for pharmacists to be able to identify and treat patients with an OUD as soon as symptoms arise. The longer the OUD goes untreated, the greater toll it will take and will affect patients across all aspects of their quality of life.

Ideally, treatment and management of OUD should reflect its balance based on the opioid pendulum. Balance on the opioid pendulum indicates the inclusion of risk stratification and principles of addiction medicine applied to opioid prescribing.

It's important for clinicians prescribing opioid medications to be cognizant of the left and right sides of the opioid pendulum, which is avoidance and widespread use. Avoidance of opioid use should not reach the point to which it affects opioid medication prescribing for patients in chronic pain.

Conversely, opioids should not be prescribed as soon as a patient complains of pain, because this can lead to normalized and widespread use. This is where the use of pain management scales is of importance to categorize the degree of pain and to determine whether the prescribing of opioids is appropriate.

Patients who acknowledge their OUD and seek therapy need emotional and psychiatric support. Generally, rehabilitation is recommended for the maintenance of patients with chronic opioid use for the goal of treatment and prevention of relapse.

Rehabilitation follows a cognitive-behavioral approach, with patients given psychological support in the form of encouragement and motivation, through education, reward cooperation, and medications that are opioid antagonists. Self-help programs related to OUD include Narcotics Anonymous.

The goal of group therapy is to achieve the maintenance of self-control and restraint. Rehabilitation enforces behaviors to patients that may negate drug use and diminish future drug addiction.

Rehabilitation must also encompass an educational component too. Patients seeking recovery should have the ability to be self-aware clinically as well of how opioids play a role in their addiction, and how consumption of opioid antagonists for treatment can minimize the addiction-related symptoms they experience.

Furthermore, patients who are undergoing the titration process to gradually minimize drug use should also be aware of the concomitant use of other drug classes, such as benzodiazepines (i.e., lorazepam), which will cause synergy and enhancement of opioid effect, interfering with opioid drug abuse treatment. (Dydyk, Gupta, and Jain, 2022).

Medications

Buprenorphine and methadone are opioid antagonists used to treat OUDs. The principle behind the use of these medications mechanistically is to reverse the induction of opioid agonist drugs synergistically on their receptors by blocking its effects and displacing its receptors on the brain, suppressing craving and withdrawal symptoms. Buprenorphine and naloxone, another opioid antagonist, are commonly used together and work centrally on the brain (IHIP, 2012).

Buprenorphine is a long-acting opioid with a recommended treatment duration for buprenorphine includes a minimum of 12 months. Buprenorphine maintenance therapy consists of induction, stabilization, and a maintenance phase.

The induction phase of buprenorohine is for those who use short-acting opioids, such as heroin, and it lasts for 7 days. The stabilization phase is marked by patients undergoing a marked reduction in craving, and that lasts about 8 weeks to reach maintenance status.

Methadone is another drug used in recovery, and although it is categorized as an oral mu agonist, it has been found to act peripherally on its opioid receptors. Methadone is specifically used for patients who are struggling with the physiologic effects of chronic opioid use by blocking euphoric effects and decreasing narcotic craving.

Because it works peripherally, methadone has been found to be non-sedating. The maintenance phase of this drug begins approximately 6 weeks after initiation of therapy. The length of the maintenance phase can last years to an entire lifetime, depending on the patient’s degree of opioid dependence ( J Pain, 2010).

It is important to note that although opioid antagonists play a role in OUD recovery, they do hold risks of addiction in themselves as drugs of the opioid class. Therefore, discontinuation of these drugs requires close monitoring of the patient because it may lead to relapse.

In these instances, cognitive behavioral therapies that include rehabilitation illustrate that medication reversal use should not be the only component for OUD recovery if intending on taking care of the patient’s health long term

Conclusion

OUD is a disease that affects millions of people worldwide and has deteriorating effects on quality of life. Many factors play a role in the development of OUD, which include but are not limited to social, environmental, genetic, and psychosocial factors.

It is crucial for clinicians and pharmacists to work together to find solutions that individualize the use of opioids where appropriate and offer treatment for instances in which there is chronic and excessive use. Collective education and awareness for health care professionals and patients on the causations and minimization of opioid abuse is needed to help alleviate the opioid epidemic crisis.

Bibliography

DSM-5 Criteria for Diagnosis of Opioid Use Disorder - Asam. https://www.asam.org/docs/default-source/education-docs/dsm-5-dx-oud-8-28-2017.pdf?sfvrsn=70540c2_2.

He, Li, et al. “Methadone Antinociception Is Dependent on Peripheral Opioid Receptors.” The Journal of Pain, U.S. National Library of Medicine, Apr. 2009, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952445/.

IHIP, Author(s): and HRSA HIV/AIDS Bureau (HAB). “Module 7: Buprenorphine: Know the Facts.” TargetHIV, 1 Aug. 2012, https://targethiv.org/ihip/module-7-buprenorphine-know-facts.

Opioids. (2020). In LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. National Institute of Diabetes and Digestive and Kidney Diseases.

Opioid Use Disorder - Statpearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK553166/.