Addicts of heroin and prescription drugs such as codeine and morphine might be able to break their dependence without severe withdrawal symptoms, Stanford scientists announced Tuesday.
Researchers found that a commonly used pain medicine also blocks the specific brain receptors that cause withdrawal symptoms for opioid addicts. The medication, called ondansetron or Zofran, is often used for chemotherapy patients suffering from nausea, is not addictive and has few side effects.
The study was released online Tuesday in the Journal of Pharmacogenetics and Genomics.
Opioid abuse is a serious and growing problem, said Dr. Larry Chu, the study's lead author and an assistant professor of anesthesia at Stanford's School of Medicine. About 12.5 million Americans aged 12 and older used prescription pain medicine for non-medical purposes in 2007, according to a government National Survey on Drug Use and Health.
Addicts undergoing opioid withdrawal have symptoms including nausea, vomiting, diarrhea, insomnia and agitation. Currently, those symptoms are often treated with other opiates such as methadone and buprenorphine, "simply switching one opiate for another, so the patient is never fully detoxified," Chu said.
Another treatment uses the drug clonidine, which can cause severe drops in blood pressure and has to be closely supervised.
"Really we don't have any truly effective ways to treat opioid withdrawal in an outpatient setting,"Chu said.
The Stanford researchers began their study using mice, which develop addictions similar to humans and also display withdrawal symptoms. Using genetic mapping, researchers determined there was one particular gene and brain receptor responsible for determining the severity of opioid withdrawal symptoms. They then had to find a drug to block that receptor.
"We were very lucky," Chu said. "It turned out such a medication already existed and had been approved by the FDA."
The medicine worked well for the mice, and since the drug was already approved , the scientists were immediately able to test their theory on humans in a small study. Eight non-addicted humans were given morphine in one session, and then morphine plus the ondansetron in another session. When they received the ondansetron, their withdrawal symptoms were significantly reduced.
Chu said they plan to conduct a larger study, and hope to ultimately move the research "out of the lab and into the detoxification center."
By Diana Samuels
Daily News STAFF WRITER
Posted: 02/18/2009 07:53:57 AM PST
E-mail Diana Samuels at [email protected].