(Medical Xpress)—A nationwide survey of opioid drug abusers in rehab indicates that because of the high it produces, the prescription painkiller oxycodone is the most popular drug of choice. Hydrocodone, also prescribed to treat pain, is next in line. In all, some 75 percent of those surveyed rated one of these drugs as their favorite.
Researchers at Washington University School of Medicine in St. Louis and Nova Southeastern University in Miami questioned more than 3,500 people in 160 drug-treatment programs across the United States, asking which drugs they abuse and why. Oxycodone was favored by 45 percent, and hydrocodone was preferred by about 30 percent. Although the drugs are meant to be taken orally, almost 64 percent of oxycodone abusers and just over one-quarter of hydrocodone abusers crushed the tablets and inhaled the drug, while one in five oxycodone abusers reported that they sometimes dissolved the drug in water and injected it. Less than 5 percent reported taking hydrocodone intravenously.
Personality, age and gender all played a role in drug preferences, the research showed. Oxycodone was attractive to those who enjoy taking risks and prefer to inject or snort drugs to get high. Young, male drug users tend to fit that profile.
In contrast, hydrocodone is the more popular choice among women, older people, people who don't want to inject drugs and those who prefer to deal with a doctor or friend rather than a drug dealer.
The research is published in the current issue of the journal Pain.
"Opioids are prescribed to treat pain, but their misuse has risen dramatically in recent years," said principal investigator Theodore J. Cicero, PhD, a Washington University researcher who studies prescription drug abuse. "Our goal is to understand the personal characteristics of people who are susceptible to drug abuse, so we can detect problems ahead of time."
For example, Cicero's team wants to find better ways to identify people who visit doctors and fake pain, as well as those who are in pain but at high risk of becoming dependent on pain-killing drugs.
Oxycodone is commonly sold under brand names such as OxyContin and Percocet. Hydrocodone is the chemical name for the opioid in the drug sold as Vicodin, among other brand names.
Among those surveyed, 54 percent said the quality of the high was considered much better for oxycodone, compared with 20 percent who preferred the high they got from hydrocodone.
"Among the reasons addicts prefer oxycodone is that they can get it in pure form," Cicero said. "Until recently, all drugs with hydrocodone as their active ingredient also contained another product such as acetaminophen, the pain reliever in Tylenol. That turns out to be very important because addicts don't like acetaminophen."
Acetaminophen causes considerable irritation when it's injected, and when taken orally in large amounts, it can cause severe liver damage, he explained.
"Interestingly, addicts, while they're harming their health in one respect by taking these drugs, report being very concerned about the potentially negative side effects of acetaminophen," said Cicero, a professor of neuropharmacology in psychiatry.
Those side effects, combined with a preference for the high provided by oxycodone, have led drug abusers to seek out that drug, either on the street or by visiting physicians and attempting to convince doctors that they have pain severe enough to warrant a prescription pain killer.
Cicero is concerned with the U.S. Food and Drug Administration's (FDA) recent approval of a new, pure form of hydrocodone without acetaminophen, a formulation he expects will be attractive to abusers.
As part of the research, the investigators conducted a pair of anonymous surveys and longer, follow-up interviews with 200 patients willing to give up their anonymity to answer personal questions about drug use.
The study also found that even among people in treatment for drug dependence, there seems to be little appetite for moving to stronger prescription narcotics such as fentanyl or various derivatives of morphine.
"Addicts will crush OxyContin pills and inject or snort them to get high, but they don't seem to want to take more potent prescription drugs," he said. "Those drugs—such as hydromorphone, fentanyl and dilaudid—have a pretty small safety margin. When you look at the dose to produce euphoria versus the amount required for overdose, it's a pretty small difference. Even serious drug abusers said they try to avoid those drugs."
But, as Cicero reported last year in The New England Journal of Medicine, some abusers are moving from abusing prescription drugs to "street" drugs. Since the introduction in 2010 of a formulation of OxyContin that is harder to snort or inject, large numbers of oxycodone users have reported switching to heroin.
"It's a huge issue, and it's a difficult one to deal with," Cicero said. "Heroin actually has become a cheaper alternative to prescription drugs, and that's a frightening development because you've now got people who never would have considered using heroin, but they're making the transition."
Another key finding from the surveys is that not all drug abusers in treatment got there through thrill-seeking or because they were looking for a great high. Many sought out pain-killing drugs because they were in pain.
"We found that about 50 percent of people, even those who have 'graduated' to drugs like heroin, indicated that they started taking these drugs because they had difficulty controlling pain," Cicero explained. "That's very different from some users who told us they just wanted to get high."
Cicero TJ, Ellis MS, Surratt HL, Kurtz SP. Factors influencing the selection of hydrocodone and oxycodone as primary opioids in substance abusers seeking treatment in the United States. Pain vol. 154 (12), December 2013, published online Nov. 25, 2013. dx.doi.org/10.1016/j.pain.2013.07.025