FORS-2107EL Lecture Notes - Lecture 10: Biotransformation, Alcohol Dehydrogenase, Depressant
27 Jun 2018
School
Department
Course
Professor
Forensic Science - Day 10 2018.02.15
Alcohol
Alcohol Toxicology
-Alcohol is pervasive in our society, and due the frequency of consumption and
severity of behavioural and health effects, figures prominently in forensic casework
-Mainly: Sexual assault, impaired driving, assault/homicide
Pharmacological Concepts
-Pharmacology is divided into 2 main concepts
-Pharmacokinetics: what the body does to the drug (ex. absorption, distribution,
metabolism/ elimination)
-Pharmacodynamics: the effects of the drug on the systems on the body and drug
interaction (Drug effects and drug interactions)
-The concentration of drugs in the blood will be in equilibrium with the concentration of
drug in the tissues
-Factors affecting this:
-Dose
-Rate of “infusion”
-Rate of metabolic break down of the drug
-Time since ingestion
-This follows the bathtub model
-When you are staring at your bathtub and you have no plugs. When you turn on the
tap, with a few drops, it will all go down the drain. But if you allow the tub to run at full
intensity, the tub can only drain at a specific rate. So the “concentration” of the liquid
in the tub will be regulated by the amount of water out by the amount of water in, so
the amount of water going in and at what rate
-This will occur through absorption from the blood into the desired organ
-Since we can’t take a part of tissue in a living person to analyze the concentration of
drug in tissue, therefore the easiest thing to do is to use blood concentration
Factors affecting Ethanol (Alcohol) absorption
-The presence of food
-Alcohol concentration in beverage (rate maximal: 20% alcohol v/v)
-Dose (# of drinks)
-Rate of ingestion
-Most of a dose is absorbed within 15 min of ingestion
-Peak BAC (blood alcohol concentration) usually reached within 30 min (under social
drinking conditions, not funnelling), but absorption may continue for some time after
-There may be a plateau period for up to 2 hours
-Here you are still absorbing but you are eliminating at the same time, so it is at
equilibrium
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Document Summary
Alcohol is pervasive in our society, and due the frequency of consumption and severity of behavioural and health effects, gures prominently in forensic casework. Pharmacology is divided into 2 main concepts. Pharmacokinetics: what the body does to the drug (ex. absorption, distribution, metabolism/ elimination) Pharmacodynamics: the effects of the drug on the systems on the body and drug interaction (drug effects and drug interactions) The concentration of drugs in the blood will be in equilibrium with the concentration of drug in the tissues. Rate of metabolic break down of the drug. When you are staring at your bathtub and you have no plugs. When you turn on the tap, with a few drops, it will all go down the drain. But if you allow the tub to run at full intensity, the tub can only drain at a speci c rate.
