Patients with histories of heavy drinking who took nalmefene as needed to curb desire for alcohol had fewer days of heavy drinking per month than peers who took placebo, but both groups significantly reduced their alcohol intake, according to an article in the July issue of Alcoholism: Clinical & Experimental Research.

The findings come from a study of 403 heavy drinkers in Finland, who took either placebo or nalmefene on an “as needed basis.”

“It has a robust and sustained effect in reducing harmful heavy drinking in a large study population,” said researcher and lead author Dr. Sakari Karhuvaara. “Alcohol problems have huge negative impacts on the well-being of individuals and families and cause enormous costs to society due to lost working days, accidents, treatment of alcohol-related disease, etcetera.”

Before the study, patients assigned to nalmefene reported 15.5 average heavy drinking days each month. They were directed to take the drug whenever they felt a looming urge to drink. During the first three months of treatment, the average number of heavy drinking days was 8.6 to 9.3 for the nalmefene group.

Patients assigned to placebo had somewhat less dramatic reductions, averaging 16.2 heavy drinking days per month before the study and 10.6 to 12.0 during the trial.

Researchers double-checked participant-reported alcohol consumption changes with tests that measured alcohol-use biomarkers in the blood.

“Alcohol dependence is nowadays recognized as a chronic, recurring disorder where relapses almost inevitably occur during and after the treatment,” Karhuvaara said. He added that focusing on harm reduction in the short term is often much more feasible than complete abstinence.

Karhuvaara is a physician and health researcher who was once an employee of Biotie Therapies Corp., the manufacturer of nalmefene. The drug maker supported the new study.

“There are fair amounts of good data (showing) that the more drinks you have a day, the more likely you are to have health or social consequences,” said alcohol researcher Raymond Anton, who did not participate in the Finnish study but has conducted research with nalmefene. “The thinking is that if you can reduce heavy drinking days or the number of drinks per drinking day, you might actually alleviate some suffering, even though you don’t cause the person to be abstinent.”

The Finnish researchers noted side effects in the nalmefene group, including nausea and abdominal discomfort, as well as energy and sleep difficulties. However, most study participants remained in the trial and continued using the drug. No analysis was done to examine whether development of side effects correlated with days without heavy drinking.

Nalmefene is an opioid antagonist that works to block the effects of endorphins. The U.S. Food and Drug Administration has not approved nalmefene for use in alcohol treatment; the drug is primarily available in investigational studies.