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.