Prescription opioid abuse has reached epidemic levels in the past 15 years. Scientists investigating why people favor one drug over another have found that oxycodone and hydrocodone are the drugs of choice for 75% of opioid-dependent individuals. Their results, published in the current issue of PAIN®, show that oxycodone was the most popular drug overall because of the quality of the high for those who sought such effects. Nonetheless, hydrocodone remains one of the most popular primary drugs, even though it has lower euphoric qualities. In addition, users say they are concerned about acetaminophen poisoning since, until recently, all hydrocodone products contained non-steroidal anti-inflammatory drugs.
Opioids used to manage pain in general medicine and dentistry are not only well known for their analgesic properties, but also for their ability to produce a high. Although most opioid classes have seen increases in their misuse, hydrocodone and oxycodone, which are the most commonly prescribed opioids in the United States, are by far the most popular drugs of choice among prescription opioid abusers. Both drugs have a long history of use for nontherapeutic purposes.
Investigators from the Department of Psychiatry at Washington University in St. Louis (Missouri) and the Center for Applied Research on Substance Use and Health Disparities at Nova Southeastern University in Miami, Fla., sought to identify the factors that influence the choice of primary drugs of abuse in 3,520 opioid-dependent individuals entering drug-treatment programs across the United States. Prospective participants were identified through the ongoing nationwide Survey of Key Informants' Patients (SKIP) program. That program is a key element of the postmarketing surveillance system, Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS®) System. SKIP consists of more than 150 treatment centers, both public and privately funded, and is geographically balanced with urban, suburban, and rural patients.
To help determine the choice of one opioid over another, researchers used anonymous, self-administered surveys to assess the influence of sex, age, race/ethnicity, area of residence, source of income, health-care coverage, drug-use patterns, and other decision-related factors.
To add richness to the study, investigators also recruited 200 patients who previously had completed the SKIP survey and indicated that they were willing to give up their anonymity to participate in a follow-up study using non-structured, qualitative interviews, dubbed Researchers and Participants Interacting Directly (RAPID).
Oxycodone was the choice of significantly more users (44.7%) than hydrocodone (29.4%) because the quality of the high was viewed to be much better by oxycodone users (54%) than hydrocodone users (20%). Far fewer participants selected any other opioid as their primary drug. While 90% of users selected mood alteration as a reason for using their primary drug, a very large percentage of each sample - 50% to 60% - indicated that the treatment of pain was also a factor in their use. This finding suggests that, in the view of many patients, pain was inadequately managed.
Despite its high abuse rates among prescription opioid abusers, hydrocodone is viewed as less attractive than oxycodone by active abusers because, unlike many oxycodone products that are 100% oxycodone, hydrocodone is frequently combined with acetaminophen. This can deter users from increasing the dose in order to get high.
Oxycodone users are more likely to tamper with their drugs in order to inhale or inject the drug. The introduction of an OxyContin abuse-deterrent formulation in 2010 led to a significant drop in the use of OxyContin, but the overall impact on total oxycodone users was not sufficiently significant to change the rank of order of abuse rates; oxycodone products remained more popular than hydrocodone products.
A key question the researchers set out to answer is why hydrocodone remains one of the most popular primary drugs even though it produces a lower quality of high and raises the potential for acetaminophen poisoning.
"The data show that hydrocodone is popular because it is relatively inexpensive, easily accessible through physicians, friends, and families, and is perceived as relatively safe to use, particularly by risk-averse users. This group includes generally risk-averse women, elderly people, non-injectors, and those who prefer safer modes of acquisition than dealers, such as doctors, friends, or family members," says Theodore J. Cicero, PhD, of the Department of Psychiatry at Washington University in St. Louis. "In contrast, we found that oxycodone is much more attractive to risk-tolerant young male users who prefer to inject or snort their drugs to get high and are willing to use riskier forms of diversion despite paying twice as much for oxycodone than hydrocodone.
"It is clear that not all drug abusers share the same characteristics," he continues. "The decision to use one drug over another is a complex one, largely attributable to individual differences such as personality, gender, age, and other factors. Prevention and treatment approaches should benefit from this because it may help prescribing physicians determine which drug to prescribe and monitor for abuse."