Stuart Wolpert, Medical Xpress, September 27, 2011
Recent research has found that a gene variant may predict naltrexone treatment success for alcoholism. About 50 percent of patients of Asian descent have a particular mutation that makes them likely to benefit from naltrexone, compared with about 20 percent of Caucasians and less than 5 percent of African Americans, said lead study author Lara Ray, an assistant professor of psychology and director of the UCLA Addictions Laboratory.
The findings are currently available online (http://1.usa.gov/ojdjPJ) in the journal Neuropsychopharmacology and will be published in an upcoming print edition of the journal.
The mutation in question is in the OPRM1 gene, which codes for the mu opioid receptors in the brain. People with “AG” or “GG” variants of OPRM1 have better clinical alcohol-treatment outcomes with naltrexone than those with the “AA” variant, Ray said, adding that approximately half of Asians have at least one copy of the “G” nucleotide at the particular location.
Ray’s laboratory conducted a study that tested the effect of naltrexone versus a placebo in heavy drinkers of Asian descent. In the study, 35 participants received alcohol in the laboratory through an infusion of ethanol that was the equivalent of two to three standard alcoholic drinks. They completed two alcohol sessions, one after taking naltrexone and one after taking a sugar pill.
“Our results revealed that naltrexone reduced the positive feelings of alcohol intoxication among individuals with the ‘AG’ or ‘GG’ genotypes but not among those with the ‘AA’ genotype,” said Ray, who is also a faculty member with the UCLA Brain Research Institute and the department of psychiatry and biobehavioral sciences at the Semel Institute for Neurscience and Human Behavior at UCLA.