A drug touted as a miracle cure for alcoholism and prescribed for this purpose in France, may work no better than counselling, Dutch researchers said Wednesday.

Without proof of its efficacy, prescribing high doses of the drug known as baclofen may be irresponsible, they warned.

"Prescribing baclofen widely as it currently happens in France might be premature and should be reconsidered," a Dutch research team wrote in the journal European Neuropsychoph armacology.

French health authorities approved use of the drug, originally designed and widely used to treat muscle spasms, two years ago for the treatment of alcoholism.

Many people in other countries are thought to use the drug without a prescription to fight alcoholism.

Interest was sparked in 2008 by a book, "Le Dernier Verre" (The Last Drink), by French-American cardiologist Olivier Ameisen, who claimed to have self-treated his alcoholism with high doses of baclofen.

A subsequent French trial found high doses of the drug caused a significant percentage of heavy drinkers to give up or moderate their intake.

Several trials since then have come up with contradictory findings.

The latest study was the largest randomised, double-blind, placebo-controlled trial -- widely considered the gold standard for drug trials, said the researchers.

Volunteers are randomly divided into groups -- some receiving the drug and others a dummy "placebo" pill without the participants or the researchers knowing who is getting what.

The study enrolled 151 people from alcohol treatment centres in The Netherlands. They were divided into high-, low- and no-dose groups, and all received psychological counselling throughout.

Comparing the outcomes, the group concluded that "neither low nor high doses of baclofen were effective in the treatment of AD (alcohol dependence)."

There was no difference in relapse speed or rates between the groups.

"We need to consider safety and side-effects," said study co-author Reinout Wiers from the University of Amsterdam.

"We are not closing the door on baclofen, but we are saying that we need more research."

According to the World Health Organization, 3.3 million deaths around the globe every year are the result of harmful alcohol use -- almost six percent of all deaths.