Most people who take zolpidem – the generic name for Ambien – have insomnia and want to fall asleep. But can the drug help some people wake from an unconscious state?
For years ReGen Therapeutics in London has been working on a “zolpidem project.” It is developing new, low-dose, non-sedating formulations of zolpidem; the goal is to use zolpidem to reverse “brain dormancy.”
Now the Moss Rehabilitation Research Institute (MRRI) in Philadelphia has announced that it will launch a federally-funded study of zolpidem. It intends to enroll about 100 people who are in a vegetative or minimally conscious state due to brain injury. The study will be led by Dr. John Whyte.
The NINDS reports that people in a vegetative state are unconscious and unaware of their surroundings; but they maintain a sleep-wake cycle and periods of alertness. A person who remains in this condition for more than a month is in a “persistent” vegetative state.
In May Whyte published a study involving 15 people; each person was vegetative or minimally conscious. They were given 10 mg of zolpidem by a feeding tube.
One vegetative participant had a significant response; he became minimally conscious. This effect was repeated in a replication assessment. But the other 14 people showed no improvement.
Some previous studies of zolpidem have yielded dramatic results.
A 2008 report from Stanford described a 35-year-old man with a brain injury; eight months after the injury he was given zolpidem twice a day. This produced an increase in his alertness, speech and movement.
A similar case occurred in Israel. It involved a 50-year-old woman with a brain injury. After taking zolpidem she regained the ability to speak and feed herself. The effect would occur within 45 minutes of taking the drug; it would last for three to four hours before she returned to her former state. The effect was repeatable on a daily basis.
A 2006 study involved three people; each had been in a permanent vegetative state for at least three years. Daily response to zolpidem was monitored for three to six years. The study found a long-term improvement in brain function.
But a 2008 report from the U.K. was less promising. It involved a 44-year-old man; four years after a traumatic brain injury he remained minimally conscious. On zolpidem he showed no improvement; by some assessments his condition worsened.
Exactly how might zolpidem improve brain function? Why do some people show no response to the drug? These questions remain to be answered.
Saturday, September 12, 2009
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