Two medications could help tens of thousands of alcoholics quit drinking, yet the drugs are rarely prescribed to patients, researchers reported on Tuesday.

The medications, naltrexone and acamprosate, reduce cravings for alcohol by fine-tuning the brain’s chemical reward system. They have been approved for treating alcoholism for over a decade. But questions about their efficacy and a lack of awareness among doctors have resulted in the drugs’ being underused, the researchers said.

Less than a third of all people with alcohol problems receive treatment of any kind, and less than 10 percent are prescribed medications. The Affordable Care Act requires that insurers provide coverage for substance abuse treatments and services, and addiction specialists expect to see increases this year in the number of people seeking help for alcoholism.

George Koob, the director of the National Institute on Alcohol Abuse and Alcoholism, said the new study should reassure doctors that naltrexone and acamprosate, while not silver bullets, can help many patients.