Vivitrol, an injectable, once-monthly version of the alcoholism drug naltrexone, has been approved by the U.S. Food and Drug Administration (FDA), the Associated Press reported April 14. Vivitrol was developed by Alkermes, Inc., and is marketed by Cephalon, Inc.

The FDA previously approved daily doses of naltrexone for treatment of alcoholism, but experts say the monthly injections -- along with counseling -- may increase compliance among patients. "Daily adherence to a medication is challenging for most people, and even more challenging for people with alcoholism," said Alkermes CEO Richard Pops.

Naltrexone, which blocks craving for alcohol, was approved for treatment of alcoholism in 1994. "Black box" warnings on Vivitrol packages will advise patients that the drug carries the risk of liver damage.