Most of the people in the Kripke study were taking Ambien or Restoril. Sanofi-Aventis, the maker of Ambien, notes that the Kripke study has a number of shortcomings.
"Ambien has more than 17 years of real-world experience and is safe and effective when prescribed and taken according to its labeling," Sanofi says in a statement sent to WebMD. "Ambien should be prescribed in strict adherence to its labeling and patients should take their medication as prescribed. The Ambien labeling carries specific warnings against driving and against intake of alcohol together with Ambien."
Experts Weigh in on Sleeping Pill Danger
In 2010, as many as 1 in 10 Americans used one of the sleeping pills in the Kripke study. Can they really be that deadly?
Experts consulted by WebMD note that the Kripke study certainly raises a red flag. But they all note that this study -- a look-back study based on patients for whom there is incomplete information -- is not proof that sleeping pills kill.
This "very provocative and interesting study raises a lot of questions," says Nancy Collop, MD, president of the American Academy of Sleep Medicine and director of the Sleep Center at Emory University School of Medicine.
"You cannot assume, just because you find this kind of association, that hypnotics are killing people," Collop tells WebMD. "People who go on sleeping pills are a sicker population. I know they tried to control for that, but these people simply are not as healthy."
Bryan Bruno, MD, chair of psychiatry at New York's Lenox Hill Hospital, notes that the actual number of people who died in the study is small.
"This does not establish any direct cause-and-effect relationship between hypnotic use and death," Bruno tells WebMD. "But it does remind us that these drugs have risks, and even mortality, associated with them."
Michael Yurcheshen, MD, head of the sleep fellowship program and assistant professor of neurology at the University of Rochester, N.Y., notes that much can be missed in a study that looks back at medical records rather than at the patients themselves.
"It is implausible to think that so many of these medications, spread across several different drug classes, could have the same biological effects," Yurcheshen tells WebMD.