Feb. 27, 2012 -- A provocative new study finds that people who take prescription sleeping pills -- even once in a while -- have a higher death risk than non-users.
The top third of sleeping-pill users had a 5.3-fold higher death risk. They also had a 35% higher risk of cancer, the study found.
"We are not certain. But it looks like sleeping pills could be as risky as smoking cigarettes. It looks much more dangerous to take these pills than to treat insomnia another way," study leader Daniel F. Kripke, MD, tells WebMD.
The sleeping pills in question are known as hypnotics. They include newer drugs such as zolpidem (the best known brand name is Ambien) as well as older drugs such as temazepam (the best known brand name is Restoril).
Hypnotic sleeping pills actually cause a person to fall asleep. This sets them apart from other sleeping aids, such as the supplement melatonin, which promote sleep through relaxation. Other sleep drugs described as hypnotics by Kripke and colleagues include eszopiclone (Lunesta), zaleplon (Sonata), triazolam (Halcion), flurazepam (Dalmane), barbiturates, and older antihistamines such as diphenhydramine.
Kripke, emeritus professor of psychiatry at the University of California, San Diego, began looking at a possible link between sleeping pills and death risk in 1975. Since then, he and others have published 18 studies that found a link.
In their latest study, Kripke's team analyzed 2002-2007 data from a large Pennsylvania health system. They obtained medical records for 10,529 people who were prescribed hypnotic sleeping pills and for 23,676 matched patients who were never prescribed sleeping pills.
Over an average of 2.5 years, the death rate for those who did not use sleeping pills was 1.2%. It was 6.1% for people with sleeping pill prescriptions. Even those prescribed 18 or fewer sleeping pills a year had a 3.6-fold higher death risk.
Based on these findings, Kripke and colleagues estimate that sleeping pills are linked to 320,000 to 507,000 U.S. deaths each year.
"We think these sleeping pills are very dangerous. We think they cause death. We think they cause cancers," Kripke says. "It is possible but not proven that reducing the use of these pills would lower the U.S. death rate."
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.
Sleeping Pills: Right Ways and Wrong Ways to Use Them
Collop, Bruno, and Yurcheshen praise Kripke for raising the issue of sleeping pill harm.
"One part of the Kripke study I really did like is when they point out that part of the problem with hypnotics is they are really best for people with acute, short episodes of insomnia," Yurcheshen says. "Very few insomnia drugs are approved for long-term daily use. And so it is fair to say that the long-term safety of these drugs has never been explored for use in that way."
Collop says she personally is "torn whether hypnotics are good or bad." She notes that it can be harmful to be dependent on hypnotic sleeping pills for a long period of time. They can help a person who is having a hard time falling asleep for some specific reason.
"These sleeping pills are mostly for short-term use," she says. "So the ideal patient would be someone with a very high stress level for some reason, such as the recent loss of loved one or a divorce, or for a traveler adjusting to a new time zone. This should be for a limited time period and only as needed, not on a nightly basis. In such situations these drugs are appropriate and effective."
Bruno notes that hypnotic sleeping pills affect the quality of sleep. When used too often, he says, "people don't feel as restored after sleeping with them."
He also points out that many hypnotic sleeping pills are habit forming. "For those at risk of addiction, or with other addictions, they can be dangerous," he says. "And most of these drugs increase the effects of alcohol."
Sleeping Pill Alternatives
It may sound surprising, but sleeping pills are not the best way to treat insomnia. The drugs clearly help people with short-term trouble getting to sleep. But for most insomnia sufferers, they are not the answer.
"It is pretty miserable not to be able to sleep," Collop says.
Bruno says that even when he prescribes hypnotic sleeping pills, he educates patients on proper sleep hygiene.
"This means basic education about the importance of a regular bedtime, a regular time to wake, avoiding naps, avoiding extreme physical exercise in the evening, and saving the bedroom for sleep," he says.
Kripke and all of the other experts agree that a form of short-term psychotherapy -- cognitive behavioral therapy or CBT -- is surprisingly effective for people with chronic insomnia.
Collop says it's time to see a sleep specialist if you have tried sleeping pills and they don't work any more. Looking for another brand of sleeping pill will not work.