Drugs, Impairment and Post-Incident Administration

Guest post by Dr. Michael Robertson – Independent Forensic Consulting

Dr. Robertson is a forensic toxicologist at Independent Forensic Consulting and a specialist consultant to a range of medico-legal organisations. Dr. Robertson graduated with a Doctor of Philosophy in Forensic Medicine from Monash University with a background in pharmacology, toxicology and analytical chemistry. Dr. Robertson is an expert in drug and alcohol-related matters and has assigned, supervised, performed and certified hundreds of toxicological analyses and has testified as an Expert Witness in most courts within Australia for prosecution, defence and plaintiff lawyers.   He holds membership of The Australian and New Zealand Forensic Science Society (ANZFSS); The International Association of Forensic Toxicologists (TIAFT); the Society of Forensic Toxicologists (SOFT) and The Forensic and Clinical Toxicology Association of Australia (FACTA).  He has been a member of the SOFT Drugs and Driving Committee and the SOFT Drug Facilitated Sexual Assault Committee and also serves as an invited reviewer for the international journal, Forensic Science International.

In the past quarter, IFC have reviewed a number of reports in which experts have concluded or implied that simply the presence of a drug infers impairment or that a drug has caused or contributed to an event when it was simply administered by medical professionals after the event.

Drugs and Impairment

  • The presence of a drug in blood is only consistent with use
  • Some information about dose and time of use may be inferred however in the absence of either unusually high levels in the blood or corroborating evidence of impairment i.e. observations that are consistent with the likely affect of the drug, impairment cannot be assumed due in part to issues associated with tolerance; dose; time of dose etc. etc.
  • That is, the presence of a drug or drugs in the blood does not imply impairment, simply the possibility of impairment

Post-Incident Administration

  • Drugs are often administered by paramedics at the scene of an incident or enroute to hospital. They may also be administered by hospital staff once they have arrived at hospital
  • Common medications administered by paramedics or hospital staff includes: morphine and fentanyl for pain management; Maxolon (metaclopramide) for nausea; midazolam for anxiety, among others
  • Whilst many of these drugs can impair and may show clinical signs consistent with impairment i.e. drowsiness, poor balance, confusions and slurred speech etc. they obviously played no role in the causation of the incident if administered post-incident
  • The administration of drugs should be well documented in the Ambulance and / or Hospital records

Some FAQs

  • Q: Is there a BAC at which time an individual will be visible intoxicated?
    A: Due to many variables including an individual’s tolerance to alcohol and learned behaviour i.e. ability to walk and talk whist intoxicated, there is no BAC that when reached all individuals will show signs of visibly intoxicated. That said studies have shown that at or about 0.15% it is more likely than not that one or more visible signs of intoxication will be evident e.g. poor balance, confusion, slurred speech etc.
  • Q: Does Speed (methylamphetamine) in the oral fluid imply my client was impaired?
    A: No. The presence only means that the drug has been used in the 12 or so hours prior to sample collection. Impairment would have to be established via other corroborating evidence i.e. driving behaviour, visual observation of the individual
  • Q: Do drug levels change after death?
    A: By and large, the answer is yes. Depending on when the sample was collected relative to death and from what part of the body blood was drawn (central or peripheral), drug concentrations may go up or down after death (in general, more likely up).

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2 responses to “Drugs, Impairment and Post-Incident Administration

  1. If the Prosecution in a case claim that the defendant administered a prescription drug with the intent to render the recipient unable to resist a sexual advance and unable to recall anything of the event, how important do you believe it is for the following to be ascertained as a matter of course in the preparation of the case for trial?

    1. The drug name, class and dose of the drug administered.
    2. The manner obtained. ie. Offender’s script, theft from other, bought from dealer etc.
    3. Was the drug taken voluntarily when offered, was it requested by the complainant or was it given covertly.
    4. Was the complainant experienced with the drug in question. What is the history of administration.
    5. Are there aspects of the complainant’s physiology with special relevance to the actions and metabolism of the drug administered
    6. If the drug is a member of a class of drugs that the complainant has used on prescription or may still be using, can the administered drug be specifically identified upon analysis.
    7. What other compounds, if any, did the complainant have in their system before, at the time of and after the time of administration. This would include licit and illicit drugs, including alcohol of course.
    8. If the complainant was familiar with a drug identified as a possible stupefying agent and said drug was stored in such a way that it may have been taken without the accused’s knowledge or in addition to any known to have been given by the accused, how can the Court deal with the absence of memory for the entire time period concerned?
    9. In the presence of alcohol, how can the Court determine the contribution of voluntary imbibing of alcohol relative to that of the administered drug.
    10. If stupefaction by alcohol is the complainant’s usual evening state and alcohol induced blackouts are regularly experienced, how can the effects of an administered drug be calculated?

    These are just a few of numerous questions that have arisen in offences I have encountered. I suggest that some may be difficult for even an eminent Toxicologist to determine. Am I correct that some questions fall beyond science alone to answer? What are the implications of this to justice?

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