Drugs/Forensic Toxicology Flashcards
Toxicology
Concerned with analysing samples for drugs/poisons and interpreting the significance of the results
Forensic
Reports/results are used in courts (Magistrates, Crown, Coroners)
What does section 3 of the coroners act 1887 say
The following deaths are reported to the coroner: violent, unnatural or sudden, cause of death unknown
Types of cases reported to the coroner
Addicts/drug use Sudden unexplained/natural Hanging Overdoses Road Traffic Collisions Train deaths Self-inflicted injury Fire
What samples are used in forensic toxicology
Ante-mortem serum/blood Post-mortem blood: heart blood, cavity blood (screening); femoral vein blood (screening and quantitation) Urine Stomach contents Vitreous humour Hair Liver Other - bile, mucous, powders, syringes
How is alcohol (+ acetone) tested for
Head-space GC
How is the general drug screen done
GC-MS (gas chromatography-mass spectrometry)
How is the urine drugs of abuse screen done
GC-MS
How is morphine tested for
EIA
How is cannabis tested for
GC-MS
How are amphetamines tested for
GC-MS
How is the hair simultaneous screen and quantitation screen done
GC-MS
What are some new psychoactive substances
Modafinil
Ibogaine
Flubromazepam
How does heroin overdose occur
Most respiratory depression or aspiration pneumonitis
How long after ingesting fatal doses of methadone does death occur
4-6 hours later
How heroin taken
IV injected, mix with tobacco, volatilised
What is the most fatal route of ingestion of heroin
All routes can cause OD
What is a feature of heroin use
Tolerance can develop
What is the typical maintenance dose of methadone
Tolerance can develop
5mL can kill a child, 60mL can kill a healthy adult male
Maintenance dose can vary from 5-200mL
Can benzodiazepine overdose cause death
Extremely rare to cause death alone
What is a common drug found in RTAs
Alcohol
Cannabis
What is speedball
Cocaine injected with heroin
What are the dangers of cocaine use
Cardiac dysrhythmias
Acute heart failure
Myocardial infarction
Slowly developing damage to the myocardium, ventricular arrhythmias, sudden death
What is lethal syndrome of excited delirium
Occurs in regular cocaine users within 24hours of last dose
What can prolong the effects of cocaine
Ethanol
What does large OD of amphetamine cause
Direct toxic effect on the heart
What can amphetamines cause
Hyperthermia, leading to rhabdomyolysis, leading to muscle necrosis and renal failure
Designer drug categories
Stimulants
Synthetic cannabinoids or ‘spice’
Synthetic opioids
Hallucinogenic compounds
What legal drugs can cause lethal overdose
Antidepressants Antipsychotics Analgesics Antihypertensives Anticonvulsants Solvents Hypnotics Anxiolytics Antimalarials Beta blockers Anaesthetics
Sources of drugs
Over-the-counter preparations Prescription medication Illegal street drugs Migrant population Bought over internet
Why can the post-mortem blood not be used to calculate the dose of drug taken
PM redistribution of drugs occurs
Why is cocaine overdose difficult to interpret
Degrades in PM blood
PM blood concentration and blood concentration at time of death not the same
To interpret cocaine levels: witness behaviour, cardiovascular pathology, medicinal/drug use history
Addict can tolerate high levels
Causes heart problems, death with low levels
Why is hair used in toxicology
Blood/serum, drugs typically can be detected for no more than 12 hours
Urine, drugs typically detected for 2-3 days
Hair is the only specimen can give information about long term drug use
Drugs are incorporated into hair from the blood stream during the growth phase
Hair growth approx 1cm/month – “tape-recording of drug use”
What information can be obtained from hair analysis
Can provide valuable evidence which cannot be provided by any other means
Segmental analysis provides pattern of past use
Established technique
Increasingly used in crime investigation
Seldom used in routine Coroner’s Toxicology
What drugs can be detected in hair
Morphine Cocaine Amphetamine Diazepam Analgesics Anticonvulsants Antiemetics Antihistamines Antidepressants Antipsychotics Local anaesthetic
Problems with hair analysis
Environmental contamination
Absorbed from sweat or sebum coating hair
Passive inhalation
Cosmetic treatment (Shampoo washing, Perming, dyeing, bleaching)
Hair colour
What is chemsex
Sex under the influence of drugs (MSM)
What drugs are used in chemsex
g-hydroxybutyrate/ g-butyrolactone
Methylamphetamine (crystal meth)
Mepdedrone
Harms associated with chemsex
GHB/GBL have steep dose response curves
Mixing with other drugs is dangerous
Increased risk of HIV
