Popular sleep drugs such as Ambien can leave even the healthiest older people groggy and prone to stumbling, falling and confusion when they wake up, U.S. researchers reported on Thursday.
The drug, sold by Sanofi Aventis and other makers and known generically as zolpidem, appears to act broadly in the brain and has a numbing effect for at least half an hour after waking, the researchers reported in the Journal of the American Geriatric Society.
People should not avoid taking it but should be aware of the drug's effects, advised Kenneth Wright of the University of Colorado at Boulder and colleagues.
"If you have an individual who, even when they take their sleep medications, they wake up in the middle of the night to go to the bathroom, they need to be aware that they are at greater risk of falling," Wright said in a telephone interview.
If a couple is traveling together, he added, perhaps both should avoid taking such a drug at the same time while sleeping in unfamiliar quarters.
"What this also calls for is the development of new sleep medications that are effective but are safer," Wright said.
The drug is sold generically under the name zolpidem and brand names such as Zolpimist, Edluar, Hypogen, Somidem and Ivedal.
Wright's team tested 25 healthy adults by having them walk on a beam laid on the floor to test balance, and asking questions such as simple math problems to test thinking.
All had perfect balance and clear thinking when they were awakened after taking a placebo. But 58 percent of the volunteers over the age of 60 stumbled off the beam when awakened after taking zolpidem, Wright said.
"They are walking more slowly after they have taken zolpidem and they are more unstable," he said.
"You are much groggier, much more impaired, more than twice as bad. You are slower and you can't think as clearly."
The effects were less pronounced in the adults under 60 but 27 percent of the younger volunteers were also affected by zolpidem, Wright's team found.
"These are temporary effects," he stressed. People are sometimes equally groggy after a sleepless night, so it would be important to continue taking the medications if prescribed.
The drug is extremely popular, 7 billion doses of zolpidem have been prescribed worldwide, said Wright.
Other sleep medications also have undesirable side-effects.
Triazolam, marketed under brand names such as Halcion, Hypam, and Trilam, was banned in Britain in 1991 because it could cause psychosis and paranoia, although it remains legal in certain doses in the United States and elsewhere.
"One of the things about a lot of the sleep medications is they are acting on a nerve chemical in the brain called GABA," Wright said.
GABA affects sleep but also coordination and cognition, he said.
Safer sleep medications would target the regions specifically involved with sleep, Wright said. The problem is that researchers do not fully understand where all these are and precisely how they work.