Transcript Pharmacology and Sobriety Testing

Drug Impaired Driving:
A Toxicologist Perspective
Bruce A. Goldberger, Ph.D.
Division of Forensic Medicine
Departments of Pathology and Psychiatry
University of Florida College of Medicine
Decedent Driver:
Blood THC – 62 ng/mL
“A poison in a small dose is a
medicine, and a medicine in a
large dose is a poison.”
Alfred Swaine Taylor (1859)
Legal Definition of Impairment
It is unlawful and punishable as provided in Chapter 322 and in
S.316.193 for any person who is under the influence of alcoholic
beverages or controlled substances, when affected to the extent
that the person’s normal faculties are impaired or to the extent
that the person is deprived of full possession of normal faculties,
to drive or be in actual physical control of any motor vehicle
within this state. Such normal faculties include, but are not
limited to, the ability to see, hear, walk, talk, judge distances,
drive an automobile, make judgments, act in emergencies, and,
in general, normally perform the many mental and physical acts
of daily life.
The Role of Alcohol
in Traffic Accidents
(Grand Rapids Study)
Drug Impaired Driving
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More difficult to prosecute than alcoholimpaired driving
Under-reported, under-recognized
Drugs are constant factor in traffic crashes
Full impact unknown
Source: DHHS and NHTSA
Which Drugs Can Affect Driving?
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Any drug that can affect the brain’s
perception, collection, processing,
storage or critical evaluation processes.
2.
Any drug that affects communication of
the brain’s commands to muscles or
organ systems that execute them.
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For the most part, drugs that affect the
central nervous system.
Psychoactive Substances
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CNS Depressants
CNS Stimulants
Other substances
Contemporary Analytes
Opioids
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Buprenorphine
Codeine
Fentanyl
Hydrocodone
Hydromorphone
Methadone
Morphine
Oxycodone
Oxymorphone
Tapentadol
Tramadol
Benzodiazepines
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Alprazolam
Clonazepam
Diazepam
Lorazepam
Temazepam
Contemporary Analytes
Sedative Hypnotics
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Butalbital
Carisoprodol/Meprobamate
Diphenhydramine/Doxylamine
Zolpidem
Contemporary Analytes
Inhalants
Emerging Psychotropic Drugs
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Synthetic Cannabinoids
Substituted Amphetamines
Cathinones
Toxidrome
Constellation of signs and
symptoms associated with the
ingestion of a specific poison.
Signs and Symptoms:
Depressants
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Confusion
Poor divided attention
Sedation
Droopy eyelids
Slowed reaction times
Memory effects
HGN
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Poor balance
Poor coordination
Unsteadiness
Slurred speech
Disorientation
Low b.p.
Low pulse
Signs and Symptoms:
Stimulants
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Hypervigilant
Excitability
Anxious
Self absorbed
Agitated
Paranoid
Delusional
Obsessive activity
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Rapid speech
Thought blending
Tremors
Hand wringing
jaw clenching
Dilated pupils
Elevated b.p.
Elevated pulse
Signs and Symptoms:
Opiates
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Euphoria
Sedation
Confusion
Stupor
Droopy eyelids
Slowed reaction times
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Slowed reflexes
Poor balance
Poor coordination
Constricted pupils
Low pulse
Low b.p.
Signs and Symptoms:
Marijuana
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Relaxed
Sedation
Confused
Poor divided
attention
Memory effects
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Poor balance
Poor coordination
Reddening of eyes
Eyelid tremors
Elevated pulse
Elevated b.p.
Signs and Symptoms:
Stimulant Withdrawal
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Hypersomnolence
Fatigue
Exhaustion
Withdrawal
Agitated
Paranoia
Delusions
Tremors
Chills
Stimulant withdrawal can
mimic depressant effects
Recognition of the
Drug-Impaired Driver
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First Choice: DRE
Non-DRE Officer
What is the Basis for the
Opinion of Impairment?
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Drug effect (pharmacology and toxicology)
Opinion rarely based upon the drug report alone
Must also evaluate the toxicological findings in
context of the case
DRE Matrix
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HGN
Vertical nystagmus
Lack of convergence
Pupil size
Reaction to light
Pulse rate
Blood pressure
Body temperature
Other indicators
What the Toxicologist
cannot do….
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Determine impairment in a specific
individual from a drug concentration alone
Determine exactly how much drug was
taken
Determine exactly when a drug was taken
Drug Interpretation Issues
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Individual response
Multiple drug use
Tolerance
History of drug use (chronicity
Health status
Metabolism
Genetic/Ethnic differences
Alcohol. The continued use of per se concentration limits for alcohol is
recommended. However, it is time to reevaluate the current limit of 0.08 g/dL.
Prescription drugs. A valid prescription constitutes an affirmative defense
against a per se standard, although impaired drivers can be prosecuted under
the impairment arm of a drugged driving law if they exhibit clinical signs and
symptoms of impairment. Without a valid prescription, any potentially
impairing medication present in the blood constitutes per se evidence of
drugged driving.
Alcohol and prescription drugs. Based on available evidence of additive or
supra-additive impairing effects of alcohol and other drugs, the alcohol per se
concentration should be lowered in these contexts to ≥0.05 g/dL.
Illegal/illicit drugs. Any illegal/illicit drug present in the blood of a driver
suspected of impairment should constitute per se evidence of drugged driving.
Over-the-counter medications. Drivers demonstrating impaired driving
behavior should be prosecuted under the impairment arm of the drugged
driving law.
(JAT, DuPont, Goldberger, Gold and Reisfield, 2012