Toxicology of alcohol and drugs
Toxicology of alcohol and drugs
Group 3 poisons
Diameter of pupils after drugs usage
Hypnotics and sedatives drugs
Amphetamine and analogs
A multipurpose drug screen may be applied to samples of body fluids, especially when there is a limited amount of sample. For forensic purposes, at least two uncorrelated methods of identification are required (e.g. HPLC and GC). Immunoassay methods provide good exclusion evidence, but poor confirmation of identity.
Blood and urine samples should be obtained whenever possible in this type of investigation: when the blood sample is small, the chance of detecting and confirming residual traces of an antidepressant or stimulant drug is almost zero. If there is no urine sample, pre–screening by immunoassay methods may be essential to provide an analytical guide to the nature of any drug present in the blood sample
Behaviours that might indicate potential drug use by drivers:
Smell - principally the smell of burning marijuana (cannabis)
Unusual behaviour or responses by the driver to an officer’s questions (including slow or slurred speech and physical responses), inappropriate answers to simple questions
Flat, dull, or excited behaviour
Unusually large or small pupils, unusual eye
Impairment of fine motor skills.
In general, postmortem stomach contents, blood and urine samples may be analysed by immunoassay. However, in some suspicious deaths or criminal cases, stomach contents, blood and urine samples cannot be obtained and tissue samples have to be examined.
Drug screening in non–fatal criminal cases and traffic offences. Many forensic enquiries entail analytical investigations that require detection of therapeutic drug concentrations rather than toxic concentrations. For example, in driving offences a screen is required for drugs that can impair judgement and psychomotor activities (e.g. sedatives, tranquillisers, stimulants and narcotics).
initial effects are milder than those of ethanol and toxic effects are not usually seen until after a latent period of 8 to 36 h
severe upper abdominal pain, visual disturbance proceeding to blindness, severe metabolic acidosis, and prolonged coma which may terminate in death from respiratory failure.
fatal dose varies greatly but is usually between 100 and 200 mL in adults, although ingestion of 30 mL is potentially lethal; permanent blindness has been caused by as little as 10 mL.
oxic effects are associated with blood concentrations greater than 0.1 g/L and blood concentrations greater than 0.2 g/L are indicative of severe poisoning and may be lethal.
and distributed in the body according to the water content of the tissues.
may also be
absorbed by inhalation or through intact skin
metabolised, much more slowly than ethanol, by oxidation to formaldehyde, formic acid
, and other products. Oxidation to formaldehyde is accomplished by alcohol dehydrogenase since the metabolism is inhibited by ethanol.
Maximum concentrations of formic acid in the blood and urine occur 2 to 3 days after ingestion
is readily absorbed after oral administration and slowly absorbed through intact skin. It is metabolised more slowly than ethanol; it is largely converted to acetone which is slowly excreted from the lungs and in the urine; acetone may be further metabolised to acetate, formate and carbon dioxide; some unchanged isopropyl alcohol may be excreted in the urine together with its glucuronide conjugate, particularly after large doses.
The estimated minimum
lethal dose is 240 mL. Isopropyl alcohol is about twice as toxic as ethanol and the symptoms of intoxication are similar. Fatalities have been associated with blood concentrations greater than 1.0 g/L.
Heroin (diacetylmorphine ,diamorphine )
The heroin is
metabolized to morphine and 6- monoacetylmorphine (6-MAM)
. 6-MAM is specific for heroin use.
The heroin parent drug was found in oral fluid for up to 24 h after having smoked and up to 60 min after having injected heroin. If heroin is snorted or smoked, very high levels of heroin (in the milligram per litre range) may be detected in oral fluid for several hours after use because of deposition of the parent drug in the oral cavity.
Designer drugs = new drugs = legal highs research chemicals = Novel Psychoactive Substances (NPS)
Drugs which are created to get around existing drug laws.
present in poorly controlled diabetics
at concentrations up to, and sometimes
exceeding, 80 mg/100 mL.
Acetone is also sometimes present at lower concentrations
(e.g. below 10 mg/100 ml) in chronic alcoholics, malnourished individuals and those who suffer from severe stress
The presence of both isopropanol and acetone can result from solvent ingestion (acetone is the major metabolite of isopropanol)
metabolised to glycoaldehyde and to lactic acid and oxalic acid
. Calcium oxalate crystals are deposited in the kidneys and some oxalate may be excreted in the urine together with unchanged ethylene glycol.
non–toxic and the serious toxic
effects are due to the metabolites
. In adults the
minimum lethal dose is about 100 mL although survival has been reported after ingestion of 250 mL
Toxic effects are usually associated with plasma concentrations greater than 0.5 g/L.
Symptoms: marked reduction in body weight, skin lesions, asymmetrical arrangement of facial halves, scruffy appearance
Amfetamine and metamfetamine
Readily absorbed after oral or rectal administration; rapidly distributed extravascularly and taken up, to some extent, by red blood cells. The main metabolic reaction is oxidative deamination to form phenylacetone, which is then oxidised to benzoic acid and conjugated with glycine to form hippuric acid;
The estimated minimum lethal dose in non–addicted adults is 200 mg. Toxic effects may be produced with blood concentrations of 0.2 to 3 mg/L, and fatalities with concentrations greater than 0.5 mg/L. Death from overdosage is comparatively rare.
absorbed from the gastro–intestinal tract but absorption is slow and irregular. However, Δ9-THC can be
measured in plasma within seconds after inhalation
of the first puff of marijuana smoke. Δ9-THC is lipophilic and is widely distributed in the body.
Cannabis or Δ9-THC intoxication may result in
loss of consciousness or even death, but reports of fatalities are rare.
Cocaine is normally only used as a surface anaesthetic in the eye, ear, nose, and throat because of the possibility of systemic toxic effects when given by other routes. Addicts may inject it or use it as a snuff .
The main metabolites are benzoylecgonine, ecgonine, and ecgonine methyl ester, all of which are inactive; some norcocaine, an active metabolite, may also be produced; other metabolites that have been reported are ethylecgonine, hydroxycocaine, and methylecgonidine.
Symptoms: marked reduction in body weight, skin lesions, asymmetrical arrangement of facial halves, skin tension, scruffy appearance