Toxicology Expert Witness Testifies in Vehicular Homicide Case Involving a Drug Recognition Expert


Toxicology Expert Witness

Natalie Lincoln was charged with vehicular homicide in the death of a man when the car she was driving crossed the center lane and struck the decedent’s vehicle.  At the scene of the accident, the defendant passed a field sobriety test performed by a police officer and had a negative breath test for alcohol.  First responders and paramedics described the defendant as awake, alert, cooperative, and without signs of intoxication.  When the defendant was examined in the emergency room because of injuries sustained in the accident, she was alert and oriented, and had a normal eye examination.

At 20:55, the defendant was alert and oriented.  At 21:40, 4 milligrams of intravenous morphine was administered to the defendant for back and neck pain from the accident.  A police officer and Drug Recognition Expert (DRE) was called to evaluate the defendant.  Their examination began at 21:45.  The DRE also conferred with the officer who had initially evaluated the defendant. After which a repeat breath alcohol test was administered, also negative.  The DRE collected information about the defendant’s use of medications that day, which included baclofen, adderal, and citalopram.  The DRE then performed an examination. He described the defendant as emotionally upset (crying), having dry mouth, a raspy voice, bloodshot and watery eyes. The DRE documented that the defendant was drowsy and fell asleep at the end of the examination.

The DRE performed an eye examination. It showed lack of smooth pursuit, as well distinct and sustained nystagmus in both eyes.  The angle of onset of nystagmus was less than 40 degrees in the left eye, but not the right eye.  The DRE observed vertical gaze nystagmus. The DRE documented that the exam was performed when the defendant was only wearing one of her contact lenses, because she had lost a contact in the accident.  The defendant had poor vision (20/1000). The DRE did not perform other field sobriety tests (walk and turn, one leg standing) because the defendant was immobilized in a cervical collar. The DRE report documented that the defendant was falling asleep during the examination.

Based on the DRE exam, the officer concluded that the defendant was under the influence of a depressant and narcotic analgesic. Subsequently, she was not safe to drive a motor vehicle.  A warrant was obtained for a forensic blood sample. The subsequent sample was collected approximately 2 hours after the DRE exam.  The following analysis of the blood sample was negative for ethanol and all other drugs of abuse. The sample was positive for baclofen at 0.25 mcg/mL, with the normal therapeutic range reported as 0.1 to 0.4 mcg/mL.

A jury trial ensued, with the charge of vehicular homicide being based on the DRE’s testimony that the defendant’s ability to drive a motor vehicle safely was impaired by her use of baclofen. This is a skeletal muscle relaxant and central nervous system depressant.  At trial, the DRE opined that the abnormal eye findings, including lack of smooth pursuit and sustained nystagmus, were caused by baclofen and were indicative of impairment.  On cross-examination, the DRE testified he was aware that morphine had been administered to the defendant prior to the exam. However, he was not aware of the dose or when it was administered.

The DRE testified that the presence of vertical nystagmus in the defendant was inconsistent with the use of morphine. He based this testimony on his training and a fact sheet that was issued on narcotic analgesics by the National Highway Transportation and Safety Administration.  The DRE testified that he could not recall encountering baclofen in any other examination that had had previously performed.  The DRE also testified that his training had not informed him that morphine is a central nervous system depressant. The decision matrix he used as a DRE classified it as a narcotic analgesic.

A toxicology expert witness was called by the defense. The expert’s credentials included board certification in medical toxicology and clinical experience in addiction medicine.  The toxicology expert witness opined that the defendant was not impaired by baclofen at the time of the accident.  The expert acknowledged that baclofen can cause sedation as an adverse effect, but that this most commonly occurred in the first days of treatment and goes away after repeated doses.  The expert testified that the defendant had been taking the baclofen for over three years. Furthermore, there were no reports to her treating physician of sedation or adverse effects.  Also, the levels of baclofen that were measured in the defendant’s blood were consistent with normal, therapeutic use of the medication.

The toxicology expert witness testified that the most likely explanation for the abnormal findings on the DRE examination were secondary to the morphine that had been administered intravenously, five minutes before the officer conducted his examination.  The jury was informed by the expert about scientific studies that had demonstrated that the IV administration of morphine and other opioids can affect smooth eye pursuit movements and cause nystagmus. The expert also educated the jury that over the last several years, several scientific studies had reported the observation of vertical eye nystagmus when morphine and other opioids are administered intravenously. The jury was also informed that morphine is both a central nervous system depressant and a narcotic analgesic. This is especially true when the drug is administered intravenously.

The toxicology expert witness informed the jury that some central nervous depressants, particularly alcohol, can cause abnormal smooth pursuit movements and gaze nystagmus. However, there were only several drugs that had been shown to cause these same effects. These included central nervous system depressant drugs like barbiturates, phenytoin (Dilantin), lithium, and carbamazepine (Tegretol).  The toxicology expert informed the jury that no scientific studies had demonstrated that baclofen causes the kind of abnormal smooth pursuit or horizontal gaze nystagmus findings that are performed on a DRE examination.  The expert also testified that baclofen is sometimes used in the medical treatment of conditions where people have nystagmus.

The toxicology expert witness’s summary opinion was that the defendant showed no signs of impairment or intoxication when evaluated by first responders, police officers, or treating physicians. It was not under 5 minutes after the IV administration of a significant dose of morphine that the defendant showed abnormal eye movements. These were consistent with morphine (a central nervous system depressant and narcotic analgesic).  Moreover, the facts of the case did not support that the defendant’s use of baclofen resulted in impairment or the automobile crash. After a 90 minute deliberation, the jury found in favor of the defendant.

Lessons to be learned:

  1. The DRE is performed by an officer who is not clinically trained
  2. The 12-step process that DRE’s follow to reach their conclusions does not include a review or communication with physicians or other health care providers who are involved in the care of the subject in question
  3. The DRE relies upon fact sheets developed by the NHTSA, which are over 10 years old. These include inaccurate information about important drugs like narcotic analgesics
  4. The eye exam performed by DRE’s are prone to false-positives. A substantial percentage of normal people have horizontal nystagmus at maximal deviation of the eyes
  5. The decision matrix used by DRE’s to determine the class of drug(s) that could explain the findings cannot be generalizable to all drugs. Baclofen as example

About The Author

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EXPERT WITNESS E-001702

no imageThis expert is a medical toxicologist with training and experience in addiction medicine as well as occupational, environmental, and pharmaceutical toxicology.

Location: OR
BS, Biopsychology, University of Michigan
MD, Wayne State University of Medicine
MPH, Oregon Health and Science University
Internship, Internal Medicine, Legacy Hospitals (Portland, OR)
Residency, Public Health and General Preventive Medicine, Oregon Health Sciences University
Fellowship, Medical Toxicology Fellowship, Veterans Administration Medical Center
Board Certified: Preventive Medicine with subspecialties in Medical Toxicology and Public Health
Fellow, American College of Occupation and Environmental Medicine
Fellow, American College of Medical Toxicology
Former, Assistant Professor of Emergency Medicine, Oregon Health and Science University
Former, Oregon Medical Assistant Programs, Drug Utilization Review Council Member
Former, Affiliate Associate Professor of Emergency Medicine, a Major Oregon University
Former, Affiliate Associate Professor of Environmental and Molecular Toxicology, a Major Oregon University
Current, Director of Addiction Medicine, a Substance Abuse Clinic in the Portland Area
Current, Independent Consultant in Medical Toxicology