Strange behavior by insomniacs taking prescription drugs, ranging from binge eating to having sex while asleep, have raised safety questions about anti-insomnia medications such as Sanofi-Aventis’ Ambien.
Researchers in Minnesota are studying cases where insomniacs taking Ambien got up in the middle of the night, binged uncontrollably, then remembered nothing of their actions. The researchers expect to publish data shortly.
Such sleep-induced side effects while on the medications have been around for years, but the incidence is rising because of an explosion in the drugs’ use, specialists said.
Researchers haven't found a cause for the sleep-related eating disorder, although patients with a prior history of sleep-walking and women may be at higher risk, Dr. Michael Cramer Vornemann, lead researcher at the University of Minnesota Medical School and the Hennepin County Medical Center in Minneapolis, told the "Today"show Wednesday.
"Doctors who prescribe this medication do need to engage in discussions with patients to describe and try to understand potential contributors to this behavior," Vornemann told "Today."
The researchers identified 32 Ambien users who were experiencing sleep-related eating disorders with amnesia, part of a group of studies they plan to publish, according to a report in The New York Times Tuesday. The Minnesota researchers estimated that thousands of Ambien users in the U.S. experience sleep-related eating disorders while taking the drug.
Earlier research at the Mayo Clinic found similar results, that something in Ambien causes binge eating in susceptible people, according to the newspaper.
In the Minnesota study, patients who took other, older sleep medications didn't experience the disorder, Vornemann told "Today." "This is a particular association with Ambien," he said. "However, there are newer medications similar to Ambien that have come to market and we have yet to determine that prevalence."
About 30 million people in the United States take sleep medications, according to the American Academy of Sleep Medicine. By some counts that is a 50 percent jump since the beginning of the decade. Ambien boasts 12 billion nights of patient use. Other insomnia medications are Lunesta from Sepracor Inc. and Sonata made by King Pharmaceuticals Inc.
Some of the most serious side effects are short-term memory loss, and accidents involving patients who drive the next day while still feeling drugged.
“Patients who may have engaged in this unusual behavior at night —it’s relatively rare and bizarre,” said Donna Arand, president of the American Insomnia Association.
“The daytime sleepiness — that drugged feeling that people may have — is probably the most worrisome because of the (vehicular) accidents that can occur.”
Increased use of the drugs is spurred in part by heavy advertising and patients may be using the drugs for longer periods than they are intended, experts said.
Consumer group Public Citizen warned that Ambien should only be used on a limited basis because it causes temporary amnesia, according to pharmacist Larry Sasich.
Because the Food and Drug Administration’s reporting system is voluntary and anecdotal, “we don’t know how big a problem it is ... we have no way to accurately to assess the prevalence,” said Sasich a consultant for Public Citizen.
Sanofi-Aventis said sleepwalking is a rare side effect listed on Ambien’s label and that it reports all events to the FDA. Still, it had no statistics about the prevalence of sleepwalking.
Ken Sassower, a staff neurologist at Massachusetts General Hospital in Boston said a colleague who had taken one of the sleep drugs could not recall advising residents on rounds the next morning.
“The memory issue may be an infrequent side effect, but when it occurs it can be pretty significant ... certainly that needs to be looked at in a more rigorous way,” he said.
Doctors recommended against abruptly stopping the drugs, which can cause withdrawal symptoms including seizures.
“The risk was always there; we are seeing it more now because so many more people are using the drugs,” said Merrill Mitler, program director at the sleep disorder unit at the National Institutes of Health.
Two women who claimed they became sleep-eaters while taking Ambien were among four former Ambien users who filed suit against Sanofi-Aventis in United States District Court in Manhattan last week, charging they were harmed by the drug, TheNew York Times reported.