Don't Lose Sleep Over Ambien Reports: Experts
March 20, 2006
By E.J. Mundell, HealthDay

A Colorado woman becomes violent after police find her driving in winter in a nightdress, then urinating at an intersection.

A woman in Florida balloons from a size 1 to a size 12 after years of getting up at night and binge-eating.

A Tampa Navy intelligence officer is handcuffed and threatened with dishonorable discharge after shoplifting DVDs from her base's exchange.

All of these incidents, reported last week in the New York Times and the Washington Post, shared one thing in common: The person involved claimed to have been sleeping through it all after taking the popular prescription sleep-aid Ambien .

Most said they retained little or no recollection of the events in question.

These and similar recent media reports of other bizarre behaviors while using Ambien have raised fears among the millions of Americans who take the drug hoping for a good night's rest.

According to experts, those fears may be largely 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 [U.S. Food and Drug Administration] -- most of which involved inappropriate use of the medication -- the numbers are extremely small," said Donna Arand, clinical director of the Kettering Sleep Disorders Center in Ohio, and a spokeswoman for the American Academy of Sleep Medicine (AASM).

The numbers she quoted come from the FDA's adverse events reporting database, which has tracked patient reports of medication-associated sleepwalking since 1997.

Based on those numbers, Arand said she believes that, "overall, the medications that are available are safe for almost everyone."

Experts note that Ambien and its two newer rivals in the billion-dollar sleep-aid market, Lunesta and Sonata, all work in much the same way, binding with the benzodiazepine receptor on the surface of brain cells that help control the sleep/wake cycle.

According to Dr. Michael Thorpy, director of the Sleep-Wake Disorders Center at Montefiore Medical Center, in New York City, specialists have long known that risks for sleepwalking and other "parasomnias" rise whenever people take a sleeping pill.

Sleepwalking occurs when the brain doesn't catch up with the body as it emerges into wakefulness. "These parasomnias are related to the amount of time people have been in fairly deep, slow-wave sleep," he said. "So, if a sleep agent makes you sleep more consistently, with less arousals, you're more likely to have more of these behaviors."

In fact, the package insert that comes with Ambien mentions parasomnias as a rare but potential side effect, along with temporary memory loss.

According to Arand and Thorpy, there's no hard evidence that Ambien users are more likely to experience parasomnias than people who use other sleep aids. "Maybe there is something specific that makes Ambien more likely to produce this type of behavior than other hypnotics, but that's hard to tease out at this point, because it's by far the largest medication used out there," Thorpy said.

But another expert, whose team has studied the phenomenon of Ambien-linked binge sleep-eating, takes a less ambivalent view.

"There's little doubt in my mind or those of my colleagues that Ambien can do this," said Michael H. Silber, co-director of the Mayo Clinic's Sleep Disorders Center, and president-elect of the AASM. "I don't think it's common, I think it's a very small minority of patients with Ambien who do it. But since this publicity has come up, I've had two e-mails in just the last 24 hours from patients who said they never realized what it was until they read the reports."

In sleep-eating, individuals gain weight after repeated binge-eating at night, with no recollection of having done so when they awake. "We've had patients who, as soon as they started using Ambien, started sleep-eating," Silber said. "Then they stopped Ambien and the sleep-eating went away. We first published on this a few years ago, and in the five years since, we have not seen it with other sleep medications."

Sanofi-Aventis, the French company that makes Ambien, told the New York Times that it has long known that parasomnias are a rare side effect of the drug, and it continues to report such cases. The FDA told the newspaper it is monitoring Ambien's safety record.

In the meantime, a group of U.S. litigants who claim the drug triggered dangerous parasomnias filed a federal class-action lawsuit against Sanofi-Aventis on March 6.

Why might Ambien, which was approved in 1993, be different than the newer sleep medications, Sonata, approved in 2002, and Lunesta, which became available last year?

Experts said the answer could lie in Ambien's "half-life" -- the amount of time the drug stays active in the brain. "It lingers a shorter time than Lunesta and a longer time than Sonata," Silber said. "So, it may have something to do with that half-life -- the fact that it stays around for three to five hours may be just the length that's needed to do what it does. But we're not entirely sure."

One thing that experts are sure of is that Ambien, like all drugs, must be taken as directed. In many of the reported cases, users had combined the drug with alcohol or other drugs, or taken it too soon before a hazardous activity, such as driving. "People may also be exceeding the [recommended] dose," Thorpy said. "The usual dose is 5 or 10 milligrams, but sometimes people will take 20 milligrams -- that could be a factor."

According to an AASM statement released this week, consumers should read the fine print on package inserts that come with all prescription sleep medications, to familiarize themselves with proper usage plus any potential side effects.

According to Sanofi-Aventis, the most common side effects associated with Ambien include daytime drowsiness, dizziness and difficulty with coordination. Many can be avoiding by proper dosing and avoiding alcohol.

Silber said he still routinely prescribes Ambien to his patients, but added there's a real need for awareness -- not panic -- about the drug.

"That's the bottom line: If physicians don't know about this and patients don't know about it, then they won't make that connection if they are one of the small minority who are going to get a side effect," he said. "So, what I'm hoping people will learn is that if you are prescribed Ambien, be aware that there are potential side effects, as there are with any drug. And be prepared to stop using it if these side effects develop."

SOURCES: Donna Arand, Ph.D., clinical director, Kettering Sleep Disorders Center, Dayton, Ohio, and spokeswoman, American Academy of Sleep Medicine; Michael Thorpy, M.D., director, Sleep-Wake Disorders Center, Montefiore Medical Center, Bronx, N.Y.; Michael H. Silber, Ph.D., professor, neurology, Mayo Clinic College of Medicine, co-director, Mayo Sleep Disorders Center, and president-elect, American Academy of Sleep Medicine; March 15, 2006, statement, American Academy of Sleep Medicine; March 8, 14, 2006, New York Times, March 14, 2006, Washington Post