Ambien Sleep Driving: The Problem

     Zolpidem Tartrate, sold under the brand name Ambien, is a non-benzodiazepine sedative hypnotic. The non-benzodiazepines are a class of psychoactive drugs that have pharmacological characteristics similar to the benzodiazepines, with similar benefits, side effects, and risks, although they have dissimilar chemical structures. A sedative hypnotic is a drug that depresses the activity of the central nervous system and is used chiefly to induce sleep and to allay anxiety.

     Barbiturates, benzodiazepines, and other sedative-hypnotics have diverse chemical and pharmacologic properties that share the ability to depress the activity of all excitable tissue, especially the arousal center in the brainstem. Sedative-hypnotics are used in the treatment of insomnia, acute convulsive conditions, and anxiety states and to facilitate the induction of anesthesia. Although sedative-hypnotics are generally sleep inducing, they may also interfere with rapid eye movement (REM) sleep that is associated with dreaming. It has also been noted that when administered to patients with fever some of these drugs may act paradoxically and cause excitement rather than relaxation.

Sedative hypnotics may interfere with temperature regulation, depress oxygen consumption in various tissues, and produce nausea and skin rashes. In elderly patients they may cause dizziness, confusion, and ataxia. Drugs in this group have a high potential for abuse that may cause physical and psychological dependence. Treatment of dependence involves gradual reduction of the dosage because abrupt withdrawal frequently causes serious disorders, including convulsions. Buspirone and zolpidem are among the newer non-barbiturate non-benzodiazepine sedative hypnotics.

     Zolpidem is a benzodiazepine receptor agonist with high binding affinity for the GABA receptor. It was developed as a drug with a structure different from the benzodiazepines in order to provide it with an affinity for only a subset of the benzodiazepine receptors resulting in hypnotic properties without significant anti-convulsant, anti-anxiety, or muscle relaxant properties associated with the various benzodiazepines. Therefore, Zolpidem may be said to “compete” with the benzo’s for the attention of only some of the same receptors.

     Zolpidem has been available in this country since 1993, and for several years has also been available in a time release formula. It is available in both a five milligram and ten milligram tablet. The manufacturer recommends that it only be taken when a person has eight hours available for uninterrupted sleep. The peak concentration of the drug usually appears in the bloodstream between one and a half to two and a half hours. Therapeutic levels are reported as 29 to 113 ng/ml following a 5 mg. dose and 58 to 272 ng/ml following a 10 mg. dose according to the package insert.

     By around 2005 reports of parasomnias began surfacing. These are undesirable motor, verbal, or experiential events that occur during sleep. One of the more common was uncontrolled sleep eating. Raw eggs, uncooked rice, loaves of bread – they were all fair game. Cooking – and we are not talking about dishes that are particularly appetizing – was also reported, as well as sleep walking and sleep driving.

     Initially the manufacturer, Sanofi-Aventis, took the position that four percent of the population already suffered from somnambulism, and that while “events of sleepwalking have occurred during treatment with Ambien, these instances cannot be systemically linked to the product.”

     Finally, in March of 2007 there were two important developments. First, the Food and Drug Administration demanded that the makers of thirteen sedative hypnotic drugs include warnings about possible unusual behavior including sleep driving and recommended that the manufacturers conduct clinical studies to investigate the frequency with which sleep driving and other parasomnias occur in association with each product. Second, the manufacturers notified health care providers (i.e, the doctors prescribing the stuff) that the precautions were being revised to warn patients about the possibility of sleep driving and that such “complex behaviors” had been reported. Sanofi Aventis conceded that these events could occur in sedative hypnotic naive as well as sedative hypnotic experienced persons. Ambien (Zolpidem) was not the only drug affected. The others included Butisol Sodium, Carbrital, Dalmane, Doral, Halcion, Lunesta, Placidyl, Prosom, Restoril, Rozerem, Seconal, and Sonata. While Ambien related sleep driving cases have been encountered by all DUI defense attorneys, cases involving the other drugs are rare. Nevertheless, these drugs are on the same list as Ambien, so if a defense is viable for Ambien, it should be viable for these other medications as well.

     The question remains why would someone who has taken Ambien get out of bed and eat unappetizing food, cook stranger things, drive their cars into telephone poles, and have no memory of the event? A possible explanation for zolpidem induced nocturnal behavior is that after a person is aroused from sleep, he or she will walk, drive, or eat, and subsequently not recall the event after returning to sleep because of the sedation-mediated amnesic properties of zolpidem. Another possibility is that an arousal occurred out of deep sleep with the parasomnia occurring in this electroencephalographically verifiable stage of sleep. The author believes that at least in some cases the latter has been experienced, because the drivers’ interaction with police and other individuals was extremely incoherent, their behavior was “zombie-like”, and they stared blankly at the police as if looking through them.
Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

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