WEDNESDAY, Sept. 10, 2008 (HealthDay News) -- Adolescents -- or at least adolescent mice -- are more likely than adults to become addicted to OxyContin, a widely prescribed opioid painkiller.
The authors of a study published Sept. 10 in Neuropsychopharmacology believe this may have to do with adolescents' heightened sensitivity to the "high" brought on by the drug.
But this in no way should be taken to mean that the drug, whose generic name is oxycodone, does not have a legitimate place in pain management.
"It's a proven research fact that people who use opioids, which are the most effective pain-relieving medication, on a regular basis do not get addicted and do not abuse them," said Anna Ratka, chair and professor of pharmaceutical sciences at the Texas A&M Health Science Center's Irma Lerma Rangel College of Pharmacy, in Kingsville.
According to Ratka, who was not involved in the study, "the biology of those people in pain doesn't allow them to become sensitive. The bodies of those young, healthy people who just start taking oxycodone for fun respond differently than the body of those in pain."
According to background information in the paper, abuse of prescription OxyContin is a major public health issue in the United States, particularly among adolescents and young adults.
A federal report issued last week found that while cocaine and methamphetamine use among young adults in the U.S. fell in 2007 compared with 2006, abuse of prescription pain relievers by young adults rose 12 percent, to 4.6 percent.
Ratka stressed, however, that few prescriptions are actually written for younger people -- this age group usually obtains such drugs illegally.
Addiction often begins in adolescence and young adults, when the central nervous system is still evolving.
For this study, by researchers at Rockefeller University in New York City, adolescent and adult mice were allowed to self-administer varying doses of OxyContin.
The younger mice actually took less of the drug than adult mice, possibly indicating that they were more sensitive to its effects earlier on, the authors stated. These younger mice were also more sensitive to OxyContin when they were re-exposed as adults, suggesting that early use or abuse of the drug led to permanent changes in their developing brains.
OxyContin increased dopamine levels in the striatal area of the brain, the team noted. The lowest dose of oxycodone resulted in increased striatal dopamine levels in mice who took the drug during adolescence but not in those who took it as adults.
"This study definitely supports the increased sensitivity of adolescents to oxycodone and maybe any drug with a potential for abuse," Ratka said. "This is a very good attempt to show that there's behavioral and neurobiological changes that happen in adolescents under the influence of oxycodone that can later result in higher inclinations for abuse."
Ratka said she believes that oxycodone "can set up [neurological systems] in a way that, in the future, the central nervous system becomes more sensitive to oxycodone."
The research is similar to studies done on nicotine, amphetamines and other drugs, she said.
Still, mice are mice, not humans, and humans have pain responses that are different from those in animals, Ratka cautioned.
There's more on OxyContin abuse at the Substance Abuse and Mental Health Services Administration.