Are there really people out there who have been driving in their sleep? And then claimed they couldn't remember where they had been?
CBS News correspondent Trish Regan reports that is what some people are claiming after taking Ambien, the most popular insomnia medication in the U.S.
Over 26 million prescriptions were sold last year, ringing up more than $2 billion in sales for the French pharmaceutical giant Sanofi-Aventis, the third largest drug company in the world.
Regan reports new research indicates Ambien's popularity could be contributing to accidents on the roads.
Forensic toxicologist Laura Liddicoat – reporting on tests on blood samples of 2,300 impaired drivers in the state of Wisconsin - says that in 53 of the most extreme cases of erratic behavior at the wheel, the drivers had one thing in common: they all had Ambien in their blood.
They wouldn't have, she says, if they'd been taking the drug the way it is supposed to be used – for a full night's sleep.
"Ambien has a very short half life and a quick elimination period," Liddicoat explains. "If it's taken as directed, there will be no drug left in the blood after eight hours of sleep, or at least a very low amount of the drug, so therefore it really should not be seen in drivers."
The fact that it is turning up in the lab, says Liddicoat, shows that drivers are either "not taking it before going to bed, and/or they are taking large amounts of the drug. We certainly know that in one case, there were at least seven to ten pills taken... So that's certainly not one pill before bed, or, as instructed."
"The driving was so bizarre - such as driving on the opposite side of the road, having head-on collisions," says Liddicoat of the cases sent to her office for testing. "Simply bizarre behavior - it wasn't simply weaving in the lane."
Liddicoat, supervisor of the state of Wisconsin's lab for alcohol and drug tests in impaired driving and death investigations, says the drivers were disoriented and suffered from memory loss.
Sean Joyce, who says he took Ambien, tells CBS News that those symptoms are all too familiar.
"I woke up in a cell with no memory of what happened," says Joyce, talking about an incident last year when, on a flight to England, he suddenly tore off his shirt and threatened other passengers.
"I'd gone berserk on the plane, I couldn't breathe," says Joyce, whose defense is the claim that he was under the influence of Ambien.
In a written statement, Sanofi-Aventis told CBS News that while "rare adverse events of sleepwalking have been reported... When taken as prescribed, Ambien is a safe and effective treatment for insomnia."
In press releases last year and in 2004 discussing Ambien - whose chemical name is zolpidem tartrate – Sanofi-Aventis said it is "indicated for the short-term treatment of insomnia," and there is "a low occurrence of side effects" associated with short-term use.
In May 2004, the drug company also said a 12-week clinical trial found no evidence of patients developing a tolerance or needing a dose escalation, demonstrating that Ambien "may be beneficial with long-term, intermittent use."
The company warns new users of the drug to "use caution in the morning when engaging in activities requiring complete alertness until you know how you will react to this medication." Sanofi-Aventis also says "in most instances, memory problems can be avoided" if Ambien is taken only when a patient is able to set aside enough time for a full night's sleep – defined as seven to eight hours - before the patient needs to be active again.
Sanofi-Aventis also points out that the medication is non-narcotic, a non-benzodiazepine – a class of drugs commonly used in older sleep medications such as Halcion, ProSom and Restoril - and the "safety and efficacy of zolpidem," the drug's active ingredient, "has been reinforced by 17 years of real-world use."
The problem, one expert told CBS News, is that Ambien and other sleep aids have become the first choice for the treatment of even mild insomnia. He says patients are taking too high a dose for too long a time - and that can lead to serious side effects.
Another problem, reports Regan, is that a lot of people are not just taking Ambien – they are mixing it with other drugs, or they are taking alcohol – and when you combine all those things together, that's trouble.