People taking zolpidem (or as it's better known in America,
Ambien) for insomnia have heard all the possible side effects:
sleep walking, sleep eating, maybe even sleep driving. A
study by the University of Colorado at Boulder has added yet
another side effect to the list -- and this one is just as
potentially severe as the others.
The study, which involved 25 healthy adults, showed 58 percent of
the older adults and 27 percent of the young adults who took
zolpidem showed a significant loss of balance when awakened two
hours after sleep.
This lack of balance increases the risks for nighttime falls and
potential injury.
Danger to seniors
The findings are important since falls are the leading cause of
injury in older adults. According to the study’s lead
author, CU-Boulder Associate Professor Kenneth Wright, thirty
percent of adults 65 and older require hospitalization after falls
each year.
Also unnerving, the researchers found zolpidem enhances
“sleep intertia“, or grogginess, a state that
temporarily impairs working memory when the subjects were woken two
hours after taking the drug.
"The balance impairments of older adults taking zolpidem were
clinically significant and the cognitive impairments were more than
twice as large compared to the same older adults taking placebos,"
said Wright, a faculty member in the integrative physiology
department.
Wright said this suggests sleep medication produces significant
safety risks.
To measure balance, the research team used a technique known as a
"tandem walk" in which subjects place one foot in front of the
other with a normal step length on a 16-foot-long, six-inch-wide
beam on the floor.
Negative effects
To measure mental cognition, participants were given
computerized performance tests that involved adding randomly
generated numbers.
In every test, the researchers found the study participants were
negatively effected by zolpidem.
Although, some of the negative side effects were possibly working
in conjunction with the study subjects simply being tired.
The CU-Boulder team also measured balance and cognition in older
adults who took no sleep medication and were kept awake for two
hours past their normal bedtime. They found 25 percent of these
older adults failed the tandem walking balance test, which is
consistent with what is seen in people who have insomnia.
"Just having insomnia itself increases your risk of falls, even
without sleep medication," said Wright, who also directs
CU-Boulder's Sleep and Chronobiology Laboratory.
Several billion doses of zolpidem have been prescribed worldwide,
and, along with Ambien, is marketed under several different brand
names: Zolpimist, Edluar, Hypogen, Somidem and Ivedal.
Dosage effect
Wright thinks perhaps the finding that zolpidem affected older
adults more than younger adults in balance tests may be explained
in part by the fact that both groups were given five milligram
doses on study nights. Generally, younger people are prescribed 10
milligrams -- the smaller dose could lead to fewer balance
issues.
However, "this is an area that needs more study," said
Wright.
The study results showing that both hypnotic sleep medications and
sleep inertia cause significant impairment have important public
health implications, said Wright.
In older adults, falls have caused millions of nonfatal injuries
annually and more than 300,000 fatalities worldwide.
"Falls can be very debilitating, especially when older people break
their hips and require hospitalization, causing their quality of
life to go down," said Wright.
Other risks
In addition, the cognitive impairments caused by both zolpidem
and sleep inertia may affect decision-making, including responding
to situations like fire alarms and medical emergencies as well as
caring for sick children or driving to a clinic or hospital, said
Wright.
"One of the goals of this study was to understand the risk of this
sleep medication and of sleep inertia on human safety and cognition
and to educate adults and health care workers about potential
problems," said Wright.
He points out he and the other study authors are not suggesting
sleep medications should not be used, since they have their place
in terms of treating insomnia, but “additional research is
needed.”
A paper on the subject was published Jan. 13 in the Journal of the
American Geriatric Society. Co-authors included
CU-Boulder's Daniel Frey, Justus Ortega, Courtney Wiseman and
Claire Farley. The study was funded primarily by the National
Institutes of Health.
