INTRODUCTION: WHY NOVEL FORMULATIONS?
The medical profession recognizes the clinical value of prescribed opioids in treating noncancer pain that is persistent and recalcitrant to other therapies.1 However, the clinical benefit of conventional opioid formulations falls short of the need. Although analgesia from opioids is often limited to a subset of patients who achieve benefit, long-term analgesic efficacy is uncertain, and discontinuation of therapy due to adverse events or inadequate analgesia is common.2
Furthermore, opioids are dangerous when used inappropriately. Statistics reveal a trend toward unintended harm involving opioids:
5.1 million persons in the United States used opioids nonmedically in 2010, and 2 million persons tried nonmedical opioids for the first time.3
Nonmedical prescription opioid use is responsible for more than 305,000 emergency department visits per year.4
Prescribed and diverted opioids were involved in more than 14,800 fatal poisonings in 2008, a nearly fourfold increase from 1999.5
The accurate number of deaths caused by prescription drugs is difficult to confirm because data collected by medical examiners and eventually recorded by the Centers for Disease Control and Prevention (CDC) are inadequate to understand the cause of death in many patients.6 Nevertheless, the rise in the number of unintentional overdose deaths is alarming.
Harm from opioids affects two dissimilar populations: patients who are prescribed opioids, sometimes for a long-term, to treat a pain problem, and nonpatients who use opioids without a prescription. Patients who are prescribed opioids may engage in medical misuse (e.g., overusing, mixing with unauthorized substances, and unlawful sharing with others). Nonmedical use by nonpatients can include experimentation, recreation, or use to self-medicate pain or psychiatric disorders. The spectrum of opioid misuse ranges from patients who use an extra pill in search of greater pain relief to patients and nonpatients who are suffering from the disease of addiction and who go to extreme, even illegal, lengths to obtain opioids (Fig 72-1).7
The Spectrum of Opioid Misuse: Patients and Non-Patients. The spectrum of misuse involves two different populations—patients and nonpatients—with behaviors that range from mild to severe. Motivations for nonpatients range from using non-prescribed opioids to self-treat pain, to recreation, to serious substance-use disorders. Although most patients are strictly adherent, some misuse opioids by taking them other than as directed, to self-treat uncontrolled pain, to chemically cope with a psychiatric disorder, or because of addiction.7
Motives for misuse, short of addiction, vary. Based on the self-reports of 80 nondependent, recreational users of opioids, the most common feelings obtained from opioids were to feel relaxed or mellow (80%), happy or pleasant (71%), and calm or less nervous (63%) (Fig 72-2). Most participants (55%) first took an opioid to treat pain; however, 38% first took an opioid for the purpose of getting high (...