Drugs of Abuse
Amphetamine
Amphetamine is a synthetic stimulant also known as speed,
base and whiz. It is usually found as a white, grey,
yellowish or pinky powder. It has a varied effect, from
feelings of wakefulness, alertness and increased physical
or mental activity through to restlessness, anxiety
and irritability. Excessive use, particularly intravenously,
can bring on a psychotic condition, similar to paranoid
schizophrenia. Tolerance can develop and although it
is chiefly emotional, there is an abstinence syndrome,
suggesting a mild physical dependency. Amphetamines
are absorbed easily and have a half-life of 12 hours.
Metabolism includes deamination and hydroxylation. Clearance
is pH dependent with 20-30% typically excreted in the
urine, although this can be up to 80% in acidic urine.
Regular use leads to weight loss and constipation, with
heavy long-term use reducing resistance to disease.
Barbiturates
Barbiturates are a synthetic sedative that slow down
the central nervous system and used to be regularly
prescribed for anxiety, depression and insomnia. The
effects from barbiturates have a varied duration and
are classified as ultra short, intermediate or acting.
Strong emotional, physical dependence and tolerance
to barbiturates occurs. Since the 1960 ’s they
have been increasingly replaced by benzodiazepines,
which may also be addictive but are less likely to cause
death from overdose. If abused the signs of intoxication
include confusion, unsteadiness, difficulty in speaking,
hostility and suicidal tendencies. Barbiturate metabolism
is chiefly hepatic. Metabolites and parent barbiturates
are eliminated in urine, with excretion being maximal
in alkali urine.
Benzodiazepines
Benzodiazepines are the most commonly used sedative
and are available as prescription drugs.
They include diazepam, temazepam and oxazepam. They
depress the central nervous system, have a wide range
of sedative, anxiolytic and anticonvulsant effects and
are highly addictive. Benzodiazepines tend to lose their
sedative effect with long-term use, which may lead the
user to increase the dose progressively. On stopping
the drug, a long-term user may develop withdrawal symptoms
that include anxiety, panic attacks, insomnia, nausea
and loss of appetite. Benzodiazepines may also increase
the effects of alcohol. Oxazepam is a common metabolite
of a number of benzodiazepines including diazepam and
chlordiazepoxide.
Buprenorphine
An opioid mixed agonist – antagonist used both
as a potent analgesic and in the treatment of opiate
abuse. Buprenorphine is sold under the Subutex ®,
Buprenex ® and Temgesic ® product names. Buprenorphine
is up to 40 times more potent than morphine. For pain
relief it is administered as an injection or sublingually,
using doses between 0.2 and 0.6 mg. Subutex ®, used
in the treatment of opiate abuse, is given sublingually,
in higher doses, between 0.4 and 8 mg. Buprenorphine
is extensively metabolised to nor-buprenorphine, buprenorphine
glucorinide and nor-buprenorphine glucorinide.
Cannabis
Cannabis is usually smoked, often with tobacco. It can
be in the form of a resin, dried and chopped leaves
or less commonly oil. The most pharmacologically active
compound in cannabis is Δ9-tetrahydrocannabinol
(Δ9-THC). The effects of the drug are varied and
include euphoria and laughter with sensations becoming
more vivid. The vivid sensations may give rise to imagery
and hallucinations. As the dose increases, persistent
ideas can verge on paranoia. THC and other cannabinoids
are metabolised in the liver to produce many different
metabolic compounds. Cannabinoids and their metabolites
are extremely fat soluble.
Cocaine
Cocaine is most commonly found as a white crystalline
powder, usually snorted, occasionally made into a solution
and injected. Crack, the smokable form of cocaine is
found as small lumps or ‘rocks ’. Both are
strong, short acting stimulants that produce effects
of euphoria and excitement. The physical effects include
an increase in heart rate and blood pressure, dilation
of the pupils and sweating. Larger doses can cause agitation,
paranoia and hallucinations. Very high doses may lead
to convulsions and death due to heart failure. The snorting
of cocaine can lead to mucosal constriction and eventually
necrosis and perforation of the nasal septum. Cocaine
is rapidly distributed and metabolised to benzoylecgonine.
Cotinine
Cozart provides a range of kits to detect the presence of Cotinine (the primary metabolite of Nicotine) in serum, plasma, urine and oral fluid. The tests accurately differentiate between smokers and non-smokers and are widely used by the insurance industry and in clinical research.
The non-isotopic test is straightforward to use and provides rapid results within about an hour.
The microplate system offers great flexibility, it can be used in a fully automated, high throughput system or it can accommodate low sample volumes with manual or semi-automated equipment.
The Microplate EIA assay provides a qualitative or quantitative analysis of the sample.
Flunitrazepam
Flunitrazepam is a benzodiazepine, branded under the
product name Rohypnol ®. It is prescribed as a hypnotic,
used to help with insomnia. Flunitrazepam has a prolonged
action and may give rise to residual effects the next
day, with repeated doses tending to be cumulative. Routine
use is undesirable as tolerance to the effects will
build up over 3 – 14 days of continuous use and
the user can become dependant. Long-term use will cause
a withdrawal effect when the user stops taking the drug.
Fluoxetine
Fluoxetine, also known as Prozac ®, is commonly
prescribed for the treatment of depression or obsessive
compulsive disorders and is administered in a pill form.
It is thought that these conditions are caused by an
imbalance of chemicals within the central nervous system
and Fluoxetine is believed to inhibit the release, effects
and re-uptake of seratonin, one of these chemicals.
Fluoxetine can cause insomnia, headaches and nausea
but is not considered to be a drug of dependence and
there have been no recorded overdoses associated with
the drug by itself. However, taken with other antidepressants,
it can lead to very high blood pressure, vomiting and
shock.
LSD
LSD (lysergic acid diethylamide) is a very potent hallucinogenic
drug most commonly found as a liquid, either on its
own or absorbed onto paper sheets. The effect or ‘trip’
can last up to 20 hours and the state, which it produces,
can vary. The intensity and involvement of the hallucinations
can range from feelings of euphoria to terror.
Methadone
Methadone is an opiate agonist and can be used as a substitute for opioids, preventing the onset of withdrawal symptoms. Its analgesic properties are similar to those of morphine but accumulation of the drug can produce a sedative effect.
Methamphetamine
A synthetic stimulant with mild hallucinogenic effects,
related to amphetamine and MDMA (ecstasy), usually found
in tablet form and taken orally. It causes feelings
of euphoria in the user and an increase in their respiration.
In low doses it produces mental relaxation, tense muscles,
increased sensitivity to stimuli and sometimes hallucinations.
Higher doses have amphetamine-like effects, sometimes
producing severe or fatal reactions, even after a single
dose.
Morphine
Morphine, like other opiates is a sedative that
suppresses the central nervous system. The assay identifies
morphine but has a negligible cross reactivity to codeine
and morphine-3-glucuronide.
Opiates
Opiates are analgesics that depress the central nervous
system, causing analgesia, euphoria and narcosis. They
include drugs like heroin, morphine and codeine and
are either derived from the opium poppy (opiates) or
are synthetic compounds (opioids) with similar actions.
The drug is injected, snorted or taken orally. Tolerance
will occur with frequent use and they all have the potential
for the user to become dependent. Strong opiates will
produce feelings of well being and contentment. Breathing
and the heart rate are slowed and the cough reflex is
inhibited. With higher doses there is an increased drowsiness,
sometimes leading to coma and possibly death from respiratory
depression. After several weeks of regular use, a sudden
cessation of use will produce withdrawal symptoms.
PCP
PCP is an anaesthetic that has hallucinogenic effects.
It is regarded as a very powerful drug that can have
disturbing actions. It comes in a liquid, crystal, pill
or powder form, can be smoked, snorted, swallowed or
injected and is easily absorbed. PCP abuse is associated
with intoxication and euphoria. In high doses it mimics
schizophrenia and delusions.