French drugmaker Sanofi-Aventis has been forced to defend its popular sleep pill Ambien, after recent media reports in the USA have drawn attention to rare occurrences of sleep-walking and sleep-related eating in people talking the drug.

The New York Times and Washington Post both ran stories last week about strange behaviour in people taking the drug in the hope of getting some quality shut eye, including a women that saw her weight rocket after night-time binge-eating sessions and a navy officer caught shoplifting – both claim to have been asleep at the time.

These and other similar reports in the media have sparked fears over using the product, but Sanofi-Aventis maintains that, when taken as directed, Ambien (zolpidem) “provides a safe and effective treatment to millions of men and women coping with insomnia.”

The company claims that the safety profile of Ambien is well established and clearly reported in the prescribing information approved by the US Food and Drug Administration (FDA). And, after recently conducting a thorough analysis, Sanofi-Aventis says it has not observed any significant change in that safety profile.

According to the group, the incidence of sleepwalking in the general adult population is estimated to be around 4%. Given that patients who experience sleep disorders also have an increased propensity of sleepwalking and sleep-related eating disorders, these instances cannot be systematically linked to the product, it says.

And experts seem to agree that fears over the drug’s safety are likely to be unfounded. "It may seem like there's an explosion of these cases, but when you've got 26 million prescriptions written and just 48 reported cases to the [US Food and Drug Administration] - most of which involved inappropriate use of the medication - the numbers are extremely small,” said Donna Arand, a spokeswoman for the American Academy of Sleep Medicine, as quoted by Forbes.

Ambien first hit shelves back in 1993, and pulled in sales of $1.8 billion in 2004. Late last year, a new extended-release version was given the green light by US regulators for both sleep induction and sleep maintenance, which Sanofi-Aventis is hoping will help it shake off looming copycat competition to the original product.