States that allow managed-care programs to limit prescriptions and access to pharmacy networks are hindering the use of naltrexone for treating alcohol addiction, according to research from the Substance Abuse Policy Research Program (SAPRP).

Researchers Carolyn Heinrich of the University of Wisconsin at Madison and Carolyn Hill of Georgetown University found that treatment providers were more likely to prescribe naltrexone in states where use of generic drugs is encouraged in Medicaid programs. In states where managed-care firms dictate prescription rules, however, naltrexone was less likely to be prescribed. Other barriers to naltrexone use were restricting use of Medicaid funds for addiction treatment and the use of restrictive preferred-drug lists for Medicaid patients.

Medicaid funding accounts for a large proportion of addiction-treatment spending by states.

"Naltrexone is certainly not a cure-all, but it can be a powerful therapy, it's relatively inexpensive and states have the policy levers at hand to increase its availability to alcohol addicts," said Heinrich. "We know from extensive research that only about 6 percent of people diagnosed as alcohol dependent are getting medication during their treatment and about a third of those who do not get medication cite cost or insurance as the key barrier. Revising certain state policies on prescription drugs is one way to address what is clearly a need for greater access to a clinically proven and cost-effective treatment."

The research was published in the journal Health Services Research.