Toxicology

Question 1

what is toxicology

Answer 1

the study of the adverse effects of chemicals (including drugs) on living systems and the means to prevent or ameliorate such effects

Question 2

what are the 5 different kinds of toxicologist

Answer 2

descriptive
mechanistic
regulatory
clinical
forensic

Question 3

define forensic toxicology

Answer 3

the application of the scientific study of poisons/ intoxicants to questions raised in judicial proceedings

Question 4

name a few subdisciplines of toxicology

Answer 4

post mortem toxicology
behavioural/ human performance
workplace drug testing
public health legislation

Question 5

what are the 4 main responsibilities of a toxicologist

Answer 5

1. Conduct toxicological analysis
2. Report and document
3. Consulting and testifying (court)
4. Research and development

Question 6

define poison

Answer 6

a substance that can cause illness or death of a living organism when introduced or absorbed

Question 7

who is the father of poison and what is his main quote - what does it mean

Answer 7

Paracelsus - ‘All substances can be poisons; there is none which is not a poison’ - that the dose determines toxicity

Question 8

what are the most frequent occurrences of poisoning

Answer 8

most cases result from social and economic stress or mental disorders but some are from substance abuse or even accidental

Question 9

name a few things a toxicologist can do during an investigation

Answer 9

1. Establish poisoning as cause of death
2. Investigate unlawful poisoning by a third party
3. Establish the presence of substances that may affect a person’s behaviour/ judgement
4. Detect performance enhancing drugs

Question 10

what are the 4 main roles of a pathologist

Answer 10

1. Perform medico-legal autopsies to establish the cause of death; issue death certificate
2. Estimate time of death
3. Removal of specimens to assist in the investigation
4. Prepare report, precognition and court testimony

Question 11

why are case notes important in toxicology

Answer 11

they contain the recent history of the patient, their signs and symptoms on admission/ death, what medications they are on and any lab results, which may help suggest poisoning and of which kind

Question 12

define chain of custody

Answer 12

a process that tracks the movement of evidence through its collection, safeguarding and analysis lifecycle by documenting each person who handled the evidence, the date/time it was collected or transferred, and the purpose of the transfer

Question 13

why do we ensure chain of custody

Answer 13

to demonstrate validity, ensure integrity and, security of specimens so that they are accepted in court

Question 14

what are the two common legal drugs of abuse

Answer 14

alcohol and prescribed meds

Question 15

what are the 4 common illegal drugs of abuse

Answer 15

amphetamine, cocaine, ecstasy and opioids

Question 16

what year was the misuse of drugs act passed in the UK

Answer 16

1971

Question 17

what 3 things does the misuse of drugs act (1971) state

Answer 17

that it is an offense to:
- possess a controlled substance unlawfully
- possess a controlled substance with intent to supply
- supply or offer to supply a controlled drug
allow a house, flat or office to be used by people taking drugs

Question 18

what are the 6 main classes of mis-used drugs

Answer 18

1. Opiates
2. Depressants
3. Minor tranquilisers
4. Stimulants
5. Hallucinogens
6. Other - cannabis, nicotine, volatile substances

Question 19

how do we classify drugs into three categories

Answer 19

A, B, C - based on how much a drug will affect your brain function/ activity

Question 20

what are the main roles of a forensic toxicologist

Answer 20

1. Maintain chain of custody
2. Identify drugs and poisons
3. Screen through entire body
4. Search for parent chemicals and metabolites
5. Help to suggest possible side effects on the victim

Question 21

what are the 8 types of poison

Answer 21

1. Anions
2. Corrosives
3. Gases and volatiles
4. Metals and metalloids
5. Toxins
6. Pesticides
7. Prescription and illicit drugs
8. Household chemicals

Question 22

give 3 examples of anion poisons

Answer 22

cyanide, fluoride, nitrate - things that are charged

Question 23

give 2 examples of corrosive poisons

Answer 23

sulphuric acid and sodium hydroxide

Question 24

give 3 examples of gaseous/ volatile poisons

Answer 24

ethanol, products of combustion and solvents

Question 25

give 3 examples of metal/metalloid poisons

Answer 25

iron, lead and arsenic

Question 26

give 4 examples of toxin poisons

Answer 26

plant, animal, bacterial and fungi

Question 27

which type of poison is a good example of indirect poisoning

Answer 27

pesticides

Question 28

what is the difference between acute and chronic exposure to toxicants

Answer 28

acute = contact with a substance that occurs once for only a short period of time (up to 14 days) chronic = contact with a substance that occurs over a long period of time (more than one year)

Question 29

what are the typical symptoms of poisoning

Answer 29

nausea, vomiting, seizure, coma and death

Question 30

define drugs of abuse

Answer 30

any substance used for an alternative purpose than that intended

Question 31

why are more and more synthetic drugs being produced

Answer 31

easy to produce and transport, ae cheaper and take less time to make

Question 32

what are illicit drugs

Answer 32

highly addictive substances that are illegal to sell, make and use - not used medically

Question 33

what is the limbic system

Answer 33

a region in the core of the brain where everything happens regarding highs/ addictions

Question 34

what 5 regions of the brain are included in the limbic system

Answer 34

1. Cingulate gyrus 2. Ventral striatum 3. Hypothalamus 4. Amygdala 5. Hippocampus

Question 35

what do all the regions of the limbic system communicate through

Answer 35

the nucleus accumbens

Question 39

what are the two aims of toxicological screening techniques

Answer 39

to confirm and quantify chemicals

Question 39

what are the three types of reward systems

Answer 39

mesocortical mesolimbic nigro-striatal

Question 40

name 6 techniques of toxicological screening

Answer 40

1. Immunoassays 2. Spot colour tests 3. Thin layer chromatography and column chromatography 4. Gas chromatography 5. HPLC 6. Mass spectrometry

Question 41

what are the 5 main general steps to analysis of a chemical

Answer 41

1. Separation of poison and metabolites from biological material 2. Identification 3. Confirmation of identity 4. Quantification/ concentration 5. Interpretation

Question 42

name 4 advantages of presumptive testing

Answer 42

1. Qualitative 2. Cheap 3. Quickly ID's analytes 4. Only requires a small sample

Question 42

name a few qualitative analysis observations

Answer 42

colour morphology - shape, dimensions, etc manufacture marks packaging unusual odours

Question 43

what are the three main spot tests used in toxicological analysis

Answer 43

Marquis Mandelin's Cobalt isothiocyanate

Question 44

what are the two main steps in an immunoassay

Answer 44

1. Drug is labelled with an enzyme - fluorescent molecule 2. Interaction of a drug with an antibody

Question 45

name the 3 most commonly used TDM homogenous immunoassays

Answer 45

1. enzyme-multiplied 2. fluorescence polarisation 3. cloned enzyme donor

Question 46

what does ADMET stand for

Answer 46

A = absorption D = distribution M = metabolism E = excretion T = toxicity

Question 47

what does metabolism + excretion =

Answer 47

elimination

Question 48

what is absorption mean in ADMET

Answer 48

the movement of a drug/ chemical from the site of administration into the blood stream

Question 49

name the 9 ways drugs can enter the blood stream

Answer 49

1. Intramuscular 2. ocular 3. Oral 4. Intrathecal 5. Sublingual 6. Rectal 7. Inhalation 8. Dermal 9. Intravenous

Question 50

what does distribution mean in AMDET

Answer 50

the movement of a drug/ chemical around the body, into and out of tissues and fluids

Question 51

what is the NPIS and what does it do

Answer 51

National Poisons information service - advises NHS healthcare professionals on the diagnosis, treatment and care of poisoned patients

Question 52

what causes the largest proportion of drug misuse deaths

Answer 52

accidental poisonings

Question 53

what is elimination mean in ADMET (metabolism + excretion)

Answer 53

irreversible loss of drugs - unchanged and metabolites - from the body by any mechanism

Question 54

what is excretion in ADMET

Answer 54

removal of intact drug from the body e.g. urine, faeces, breath

Question 55

define half-life and clearance in regards to excretion

Answer 55

half-life = rate of drug removal clearance = extent of drug removal

Question 56

what is biotransformation

Answer 56

major site of xenobiotic metabolism

Question 57

what is first pass metabolism and what does it do

Answer 57

GI to liver - reduces bioavailability

Question 58

name a few factors affecting the passage of drugs through cell membranes

Answer 58

- plasma protein binding - free drug concentration gradient - active transport - molecular weight - degree of isolation - lipid solubility - water solubility

Question 59

define drug metabolism

Answer 59

the enzyme-catalysed conversion of a drug into a chemically-distinct product (a metabolite)

Question 60

what's key to remember about kinetics

Answer 60

it it refers to time its usually about kinetics

Question 61

what's the difference in a kinetic graph of drug metabolism when comparing oral vs intravenous administration

Answer 61

the half-lives remain the same but the absorption phase is extremely different

Question 62

define bioavailability

Answer 62

the amount absorbed relative to the dose administered

Question 63

what is the typical shape of a dose response curve and what do they show us

Answer 63

sigmoidal - tells us the lethal dose (what dose kills 50%)

Question 64

what is the order of collection in standard postmortem specimen procedure in regards to drugs in the blood and why

Answer 64

femoral, iliac, subclavian vessels, heart - due to accumulation

Question 65

why does the heart contain an artificially elevated concentration of drugs after death

Answer 65

as blood collection increases in the heart, so does the drug concentration

Question 66

where is a more reliable matrix for drug testing after death

Answer 66

in muscles

Question 67

what are some other considerations to consider when interpreting toxicology results

Answer 67

- post-mortem redistribution - post-mortem production and loss of substances - analyte stability - post-mortem findings - route of administration - alternative source of positive findings - use of appropriate reference samples