DUI Ambien
Dr. David Benjamin testified in the Kerry Kennedy DUI Ambien case in Westchester, NY, February 27, 2014.
David M. Benjamin, Ph.D. Clinical Pharmacologist and Forensic Toxicologist testified in the Kerry Kennedy case regarding the pharmacologic and toxicologic effects of the sleeping pill Ambien (zolpidem). As of November 2014, Dr. Benjamin has testified in 12 DUI Ambien cases, and the judge or jury found the defendant “Not Guilty” in 9 of them.
Kerry’s case was a very interesting and different type of DUI Drugs case. Kerry had two medication bottles (vials) on her counter, one for one type of prescribed medication, and the other for Ambien. (see insert below) In her rush to get out of the house that morning, Kerry opened the wrong vial and took an Ambien, instead of the other medication which she usually takes in the morning. This was, in fact, a medication error, and it led to Kerry becoming impaired on the Ambien, when she had had no intention to take the Ambien.
All the vials look alike. It is so easy to mistake one for another.
According to the National Coordinating Council on Medication Error Reporting and Prevention (NCCMERP),
“A medication error is any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in the control of the health care professional, patient, or consumer. Such events may be related to professional practice, health care products, procedures, and systems, including prescribing, order communication, product labeling, packaging, and nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use.” (See NCCMERP.org, accessed October 30, 2014)
The identical appearance of the vials led to a type of medication error we call a “Look Alike Drug” problem, which in this case, also could be called a “packaging error”. Just a simple change like using a different colored cap on one vial, could minimize or avoid these types of medication errors!
The timeline is outlined below:
- Took Ambien (by mistake) when she was awake, left her house and drove
- Was fine for ~20 mins, until drug was absorbed
- Hit truck, blew out tire, but kept driving
- Appearance: drowsy, tired, confused, disoriented
- Signs: nystagmus, poor balance, unsteady gait, poor or slow coordination, slow speech, short term (antereograde) amnesia, muscle flaccidity, impaired vision, & poor performance on first Field Sobriety Tests.
My testimony stressed that there are five (5) different medication errors we teach doctors, nurses, pharmacists and students, which we call the “Five Wrongs”: Wrong Drug, Wrong Dose, Wrong Route, Wrong Time, and Wrong Patient. Kerry took the wrong drug, because both prescriptions had been dispensed in identically-appearing prescription drug vials.
It took the jury less than an hour to find Kerry “Not Guilty.”
Dr. Mark Pressman has written an excellent review of the “sleep-driving” phenomenon in which he describes three ways a person can drive while sleeping or while impaired on sleeping pills. The material is summarized below along with some additional comments I have added. The citation for the complete article is: Sleep driving: Sleepwalking variant or misuse of z-drugs? By Mark R. Pressman, Sleep Medicine Reviews 15:285-292, 2011.
Three Ways to be Impaired Related to Ambien
- Sleep Walking
- Sleep Driving
- Driving while impaired on Ambien
Sleep Walking or Somnambulism
(may or may not involve the taking of a sleeping pill)
- Was asleep and got up while still asleep and “walked around”
- Involves sleep deprivation and/or stress
- History of sleepwalking or related disorder
- Occurs 1-3 hours after sleep onset during deep sleep
- Triggered by sudden arousal such as sound or touch – Typically lasts only minutes
- Eyes are open – No Nystagmus – Asleep, not impaired!
- Will navigate in spaces known to them (comfort area)
- Absence of planning or higher cognitive function (spontaneous)
- Extremely limited social interactions or none at all (can’t interact when you’re asleep!)
- Unable to respond to police requests for documents or to exit vehicle
- May give appearance of social interaction but closer scrutiny shows they are not responding
- Unable to understand or participate in FSTs (parts of the brain are not functioning)
- No muscle flaccidity – No problem walking or standing still
- Amnesia (retrograde, i.e,, no memory of what happened during the sleepwalking)
- May become violent if blocked or confronted
Sleep Driving
- Took Ambien, was asleep, got up and drove
- Appearance: drowsy, tired, confused, disoriented
- Signs: nystagmus, poor balance, unsteady gait, poor or slow coordination, slow speech, short term (anterograde) amnesia, muscle flaccidity, impaired vision, & poor performance on Field Sobriety Tests
- Ambien (zolpidem) may or may not be found in blood. Other drugs or ETOH may be present. There is a “carryover effect” even after the drug has been metabolized to blood levels below the pharmacologic concentration.
- FDA defines Sleep Driving as “driving when you are not fully awake”
Driving while impaired on Ambien
- Took Ambien, was asleep, got up and drove
- Appearance: drowsy, tired, confused, disoriented
- Signs: nystagmus, poor balance, unsteady gait, poor or slow coordination, slow speech, short term (antereograde) amnesia, muscle flaccidity, impaired vision, & poor performance on Field Sobriety Tests
- Ambien (zolpidem) may or may not be found in blood. Zolpidem has a relatively short half-life of 1.5 – 4.5 hrs, and the half-life is shorter in women than men. Zolpidem still can have a “carryover” effect even if it is not present in blood. Other drugs or ETOH may be present.
- FDA defines Sleep Driving as “driving when you are not fully awake”
- Blood concentrations above the therapeutic level may be found indicating misuse or a second dose of Ambien was taken, perhaps during a mid-night awakening. Women metabolize the drug more slowly than men. Dose for women = 5 mg not 10 mg.
- ETOH and/or other CNS depressants also may have been taken, e.g., SSRIs, benzodiazepines, other antidepressants, opioid pain relievers, indicating that the patient did not understand the consequences of doing so, or MD gave poor informed consent warning.
- However, routine behaviors, or “automatic behaviors” that have been performed 100s or 1,000s of times, are not inhibited (e.g., driving, eating, having sex) and can be performed by people experienced in these activities.
- Patient experiences a “dissociative” reaction. During this reaction, neural connections between the Thalamus and the Cortex (especially the pre-frontal cortex or the “Executive Decision” area of the brain, involved in “making good judgments,”) are blocked and signals from the brain stem and sub-cortical areas are deactivated.
- Activities, using the lower, sub-cortical areas of the brain.
- However, primitive behaviors, originating in the brain stem, and sub-cortical areas like driving, eating, sex and violence, can be activated due to the inhibition of the frontal lobe which can no longer inhibit these activities, and allows behavior generated in “lower areas” of the brain to occur.
- Subjects experience a “dissociative or depersonalization” reaction. It is not known why the reaction happens one night and not others.
(See: Sleep driving: Sleepwalking variant or misuse of z-drugs? By Mark R. Pressman, Sleep Medicine Reviews 15:285-292, 2011.)
Ambien is a very potent sleeping pill that is capable of causing many undesirable side effects like sleep driving, sleep eating, sleep sex, bizarre behavior, aggression, and murder.
Adverse Effects of Ambien
According to the manufacturer’s labeling, Ambien (or its generic equivalent, zolpidem) can cause a number of disturbing adverse effects of the Central Nervous System (CNS) including: anterograde amnesia, a type of amnesia where you forget what happened after you took the medication, rather than before. Other alarming side effects include:
Abnormal Thinking and Behavioral Changes
Some of these changes included decreased inhibition (e.g. aggressiveness and extroversion that seemed out of character), bizarre behavior, agitation and depersonalization, and a specific type of memory loss, called antereograde amnesia. Visual and auditory hallucinations have been reported.
Symptoms also included more outgoing or aggressive behavior than normal, loss of personal identify, strange behavior, homicides, abnormal thoughts and behavior, confusion, agitation, hallucinations, anxiety, worsening of depression, and suicidal thoughts or actions.
Ambien Carryover Effects
(from the manufacturer’s labeling)
CNS Depressant Effects and Next-Day Impairment
What to tell patients!
Tell patients that Ambien has the potential to cause next-day impairment, and that this risk is increased if dosing instructions are not carefully followed. Tell patients to wait for at least 8 hours after dosing before driving or engaging in other activities requiring full mental alertness. Inform patients that impairment can be present despite feeling fully awake.
Adverse events are further classified within body system categories and enumerated in order of decreasing frequency using the following definitions: frequent adverse events are defined as those occurring in greater than 1/100 subjects; infrequent adverse events are those occurring in 1/100 to 1/1,000 patients; rare events are those occurring in less than 1/1,000 patients.
Central and peripheral nervous system: Frequent: ataxia, confusion, drowsiness, drugged feeling, euphoria, insomnia, lethargy, lightheadedness, vertigo. Infrequent: agitation, decreased cognition, detached, difficulty concentrating, dysarthria, emotional lability, hallucination, hypoesthesia, illusion, leg cramps, migraine, nervousness, paresthesia, sleeping (after daytime
dosing), speech disorder, stupor, tremor. Rare: abnormal gait, abnormal thinking, aggressive
reaction, apathy, appetite increased, decreased libido, delusion, dementia, depersonalization, dysphasia, feeling strange, hypokinesia, hypotonia, hysteria, intoxicated feeling, manic reaction, neuralgia, neuritis, neuropathy, neurosis, panic attacks, paresis, personality disorder, somnambulism, suicide attempts, tetany, yawning.