Sleep aid's rare side effects gain attention

In the past week, Donna E. Sweet, MD, has had to take the unusual step of assessing several of her insomniac patients for weight gain or other signs they might be eating, driving, walking or engaging in other behavior unbeknownst to them in the night.

The reason is a series of articles published in The New York Times and picked up worldwide about Ambien (zolpidem tartrate). The pieces, published in March, focused on people taking Ambien and gaining large amounts of weight because of uncontrolled nighttime eating and driving while under the influence of this drug.

In the wake of this attention, Dr. Sweet and others have faced a wave of patient concern and have had to contemplate how to warn those prescribed this drug of these possibilities.

"People need to take it right," said Dr. Sweet, an internist and professor of medicine at the University of Kansas School of Medicine. "You should not be taking it with alcohol, and it's not designed for a patient to take it and then wander around."

According to a statement issued by Sanofi-Aventis, the drug's manufacturer, Ambien is safe and effective when taken as directed.

The article centered on sleep-driving was based on increasing concerns of government agencies, including the National Highway Traffic Safety Administration, about the growing number of vehicle crashes involving this drug. The story about sleep-eating was based on a study of more than 30 cases gathered by researchers at the Minnesota Regional Sleep Disorders Center in Minneapolis.

Preliminary data suggest patients with multiple medical conditions who are taking Ambien at the highest dosage might be most at risk.

Warnings long have been on the label about the risk of sleep-walking and about how people should refrain from operating heavy machinery, should only take Ambien just before bedtime and should not mix the drug with other substances that can cause drowsiness. But many physicians feel it might be time to remind patients of these warnings more forcefully.

"I'm emphasizing more than I usually do that if you're on Ambien, don't wait to go to bed," said Stanley Dorst, MD, associate professor of clinical family and community medicine at the University of Missouri in Columbia. "That kind of seems like common sense, but I want to make sure that patients are using common sense when they're using this drug."

As for sleep-eating, the Food and Drug Administration is monitoring the situation. Those researching this issue would like to see it added to the drug's labeling information.

"Ambien is a very safe and effective medication," said Carlos H. Schenck, MD, who is leading this research and is a senior staff psychiatrist at the Minnesota Regional Sleep Disorders Center. "But patients and physicians should be forewarned about the possibility of sleep-eating."

Information overload?

Many physicians question if this is really necessary. Sleep-eating linked to this drug is extremely rare. With only a few dozen cases recorded out of the millions prescribed this medication every year, many question whether it is significant enough to note.

"I'm not going to object, but that seems to be a very, very small number of people to be adding it to the label," Dr. Sweet said. "The labels have almost become nonhelpful because they have so much in them."

Many physicians also say there are too many unanswered questions for them to change their practice. It's not yet clear if this is a problem only for this drug or if it can be associated with all medications in this class. Also, while this drug has been associated with this phenomenon, it's not readily apparent whether it is truly the root cause.

"Until the news about this medicine is in the medical papers, rather than 'Good Morning America,' I'm not changing my recommendations," said Ayaz Madraswalla, MD, a family physician in Stores, Conn.