The newer generation of insomnia mediations, zaleplon (Sonata), zolpidem (Ambien), eszopiclone (Lunesta), and zopiclone (Imovane), or “Z” drugs, act on specific subsets of the GABA receptor. They are commonly called “non-benzodiazepine” medications, but that the name is misleading, since they bind to the same GABA-benzodiazepine receptor complex in the brain that the benzodiazepines and alcohol bind to. The difference is that they bind to a different part of the same receptor complex. They have been marketed as having less dependency and fewer side effects than the older generation of benzodiazepine medications, and some argue that these drugs have less potential for abuse than the benzodiazepines.
However, systematic studies have not shown them to be more effective or safe than the benzodiazepines, although they cost several times more. For instance, pooling of data from three trials with a total of 96 patients showed no difference between benzodiazepines and zopiclone for time to fall asleep, although benzodiazepine treated patients slept 23 minutes longer. There were no differences between benzodiazepines and zopiclone in major side effects (adverse events). And no difference between the different Z drugs for safety or efficacy has been established. General side effects for all of these meds include memory impairment, drowsiness, headache, dizziness, nausea, and nervousness. There is no evidence to date that the risk of dependency on the Z drugs is any less than for earlier classes of insomnia medications like the benzodiazepines.
So which of the Z drugs are the best? A recent review by the UK National Institute for Clinical Evidence (NICE) in 2004 showed no difference between the different Z drugs (Sonata, Lunesta, Ambien, or Imovane) in efficacy, next day impairment, or risk of withdrawal or dependence. In addition, there were no benefits in terms of efficacy or side effects compared to benzodiazepines. At one hour Sonata has a much shorter half-life than Ambien (2.5 hours) and Lunesta (6 hours), and is therefore promoted as being associated with less drowsiness the next day. Lunesta is a pure “mirror version” of the same molecule of its parent zopiclone, and appears to have been developed as a marketing effort to leave behind the negative marketing that was associated with studies of zopiclone (done before the latest Z drugs were released) showing an increase in traffic accidents with its use. Until studies are performed to specifically address the issue, we have to assume that all of the Z drugs will eventually be found to be associated with an increase in driving accidents.
One scarier possible side effect that has been seen in patients taking Ambien is sleepwalking. Ambien increases slow wave sleep, which has been associated with sleepwalking. On March 8, 2006 The New York Times reported several cases of people getting up, walking around the house, cooking, and even driving. Cases of people who got out of bed after taking Ambien (sometimes with a glass of wine), driving, and getting into car accidents, with absolutely no memory of what happened, were also reported. Some people got up in the middle of the night and crashed their cars into parked cars, and then tried to drive away, later having no memory of what happened (Remember Patrick Kennedy?).
One man on a trans-Atlantic flight took Ambien with two glasses of wine. In his sleep, he tore off his clothes and threatened to kill himself and others. As a result, the plane had to make an emergency landing. He had no memory of the incident.
Any amount of alcohol, even a glass, greatly increases your risk of having a dangerous sleep walking accident. Also, sleepwalking has been reported more commonly for Ambien probably because it holds 85% of the insomnia medication market. It is very possible that other insomnia medications can cause the same side effect.
You can take one of these medications for a few days to get you through a dry patch of sleep problems. But if you have lasting sleep disturbances cognitive behavioral therapy has been shown to be better than drugs, and without the side effects!