The definition of Toxicology is "the study of the harmful effects of chemicals or drugs on living systems, with particular emphasis on the conditions under which they occur." - The Forensic Sciences Foundation, Inc. Career Brochure Web page. It may also be defined as "the science of poisons". -Encarta 98

Evidence such as blood, urine, stomach contents, bile, liver, kidney, lungs, brains, nail clippings, and hair are sent to the Toxicologist by the Forensic Pathologist. "The specimens ordinarily examined in cases of suspected poisoning are tissue samples from vital organs, blood or urine, food, drink, and the suspected poison itself". -Encarta 98

Analytical chemistry is used in this branch. "Forensic Toxicology is concerned with the interpretation of analytical, clinical and environmental data as it applies to law and medicine, often assisting the court in a truthful decision". - The Forensic Sciences Foundation, Inc. Career Brochure Web page.

"The Toxicologist is often asked to assist emergency room physicians in determining the etiology of the comatose patient, to assist law enforcement officers in determining the cause of unsafe driving (DWI), or to assist the medical examiner in determining the cause of death in chemical/drug related cases". - The Forensic Sciences Foundation, Inc. Career Brochure Web page.

"The first challenge presented to the toxicologist is often the rapid identification of a toxic chemical in a limited sample of blood, urine, or gastric contents. The possibilities appear to be enormous, but with the artful combination of analytical methods, historical knowledge of the patient (often minimal) and knowledge of biological specimens, the dilemma frequently unfolds to resolution within a short time". - The Forensic Sciences Foundation, Inc. Career Brochure Web page.

"Interpretation of the results often requires a team effort by combined expertise of a physician, the medical examiner and a criminalist, or an adversarial judicial process with all opinions based on reasonable scientific probability".

Here is an example of Toxicology taken from The Forensic Science Foundation's Career Brochure:

The Mickey Finn (Old story/New Drugs)

"An international entrepreneur, after a successful week, visits a local bar in an exclusive hotel in Dallas. He sports a Rolex watch from Switzerland, a diamond ring from Amsterdam, and an Italian-made suit. After a few drinks, he strikes up a conversation with an attractive woman. The next morning he is found by a hotel employee in the garage of the hotel in a state of confusion, without his watch, ring, or billfold. He is escorted the local hospital emergency room for evaluation where blood and urine are routinely collected, and a drug screen and alcohol determination are requested. A small amount of ethanol is found in the blood, and a routine urine drug screen via Thin Layer Chromatography (TLC) and immunoassay are negative. Since a robbery was reported, the police found a glass form the hotel in his car. Analysis by TLC and gas chromatography/mass spectrometry revealed the presence of lorazepam (Ativan) in the drink. Further analysis of the blood via capillary chromatography with an electron capture detector revealed the presence of nanogram quantities of lorazepam. Lorazepam in combination with ethanol may produce short-term amnesia and enhance the effects of ethanol. That is, the etiology of the drug-induced state (Mickey Finn) was explained via a combination of forensic sciences and analytical toxicology.

Mickey Finn: 'Drug(s) added to an alcohol drink to produce short-term unconsciousness allowing an opportunity for an uncontested robbery. Historically, this drug was chloral hydrate (or "knock out drops")."

Therapeutic Misadventure

"The unexplained death of a 34-year old female led to the investigation of cause of death by a medical examiner's office. An extensive autopsy investigation was essentially unremarkable except for the finding of pulmonary and hepatic congestion. Toxicology studies revealed the presence of amitriptyline (a tricyclic antidepressant) and a very large amount of its major metabolite nortriptyline. In addition, therapeutic amounts of chlorpromazine (a tranquilizer) also were found in the blood. The medical examiner's report indicated that the cause of death was drug related. This resulted in an angry response from the husband and parents of the woman. The physician explained that he had carefully prescribed only small amounts of amitriptyline, thus making it impossible for her to commit suicide. In addition, the chlorpromazine was justifiably prescribed based on the physician's clinical opinion of her unique depression.

Further investigation revealed that the phenothiazine (chlorpromazine) inhibits the metabolism of nortriptyline (the metabolite of amitriptyline), allowing it to accumulate to toxic concentrations while receiving therapeutic doses of amitriptyline. Thus, the cause of death was accurately determined via a combined effort of the medical examiner and toxicologists. Any death is tragic, but the knowledge gained may prevent future therapeutic drug interactions (therapeutic misadventures)."

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