Zolpidem ingestion, automatisms, and sleep driving: a clinical and legal case series.

STUDY
OBJECTIVES: To describe zolpidem-associated complex behaviors, including both daytime automatisms and sleep-related parasomnias.
METHODS: A case series of eight clinical patients and six legal defendants is presented. Patients presented to the author after an episode of confusion, amnesia, or somnambulism. Legal defendants were being prosecuted for driving under the influence, and the author reviewed the cases as expert witness for the defense. Potential predisposing factors including comorbidities, social situation, physician instruction, concomitant medications, and patterns of medication management were considered.
RESULTS: Patients and defendants exhibited abnormal behavior characterized by poor motor control and confusion. Although remaining apparently interactive with the environment, all reported amnesia for 3 to 5 hours. In some cases, the episodes began during daytime wakefulness because of accidental or purposeful ingestion of the zolpidem and are considered automatisms. Other cases began after ingestion of zolpidem at the time of going to bed and are considered parasomnias. Risk factors for both wake and sleep-related automatic complex behaviors include the concomitant ingestion of other sedating drugs, a higher dose of zolpidem, a history of parasomnia, ingestion at times other than bedtime or when sleep is unlikely, poor management of pill bottles, and living alone. In addition, similar size and shape of two medications contributed to accidental ingestion in at least one case.
CONCLUSIONS: Sleep driving and other complex behaviors can occur after zolpidem ingestion. Physicians should assess patients for potential risk factors and inquire about parasomnias. Serious legal and medical complications can occur as a result of these forms of automatic complex behaviors.