School Science Lessons
Drug abuse and tranquillizers
Updated: 2009-08-17
Please send comments to: J.Elfick@uq.edu.au
WARNING!
Before planning to teach any of the topics or content below, get
permission from the head of your school science department OR the
principal of your school.
Some of the information in this page was originally published by the
Australian Drug Foundation, 2006.
Table of contents
11.11.0 Drug abuse
11.11.0a Drugs terminology and classifications
11.12.0 Tranquillizers
11.11.1b Reasons students may give for trying
drugs and what the teacher can say in reply
11.11.01 Abuse of volatile substances, inhalants
11.11.1 Chroming, "huffing"
11.11.2 Petrol-sniffing
11.11.3 Alcohol abuse, ethanol
11.11.4 Amphetamines, amphetamine, epinephrine
(adrenaline) amphetamine-type stimulants
11.11.4.1 "Speed" and "base"
11.11.4.2 Ice
11.11.4.3 Ecstasy
11.11.5 Antihistamines,
histamine,dexchlorpheniramine (Polaramine)
11.11.5.1 Skin-prick tests for allergy
11.11.6 Aspirin and analgesics,
paracetamol,acetaminophen (Panadol,Tylenol)
11.11.7 Barbiturates,
phenobarbital,amylobarbital, pentobarbital,thiopental
11.11.8 Classification of barbiturates
11.11.9 Hallucinogenic drugs, hallucinogens
mescaline, psilocybin, scopolamine
(hyoscine) atropine, LSD, tryptamine, cocaine, THC cannabis
11.11.10 Cannabis
("pot", "marihuana" "marijuana", "Indian hemp", "hashish", "bhang")
11.11.11 Cocaine and crack
cocaine
11.11.12 Ecstasy
11.11.13 Designer drugs invasion
11.11.14 Morphine and derivatives, codeine,
pethidine,
heroin, methadone
11.11.15 Heroin
11.11.16
Nicotine, tobacco smoking and chewing
11.12.0 Tranquillizers
11.12.1 Tranquillizers 1, major tranquillizers,
phenothiazines,
chlorchromazine (Largactil) promethazine (Phenergan) depressants
11.12.2 Tranquillizers 2, minor tranquillizers,
benzodiapines, diazepam
(Valium) oxazepam (Seraz, Serenid) nitrazepam (Mogadon)
flunitrazepam
(Roh)
11.12.2.1 GHB
11.12.2.2 Ketamine
11.12.3 Tranquillizers 3, minor tranquillizers,
dibenzazepines,
imipramine (Tofranil) desipramine (Pertofran) amitriptyline
(Tryptanol) nortriptyline (Allegron)
11.12.4 Drug interactions
11.12.5 Drug tolerance
11.11.0a Drugs
terminology and classifications
11.11.1a
Addiction
11.11.2a Classification of drugs
11.11.3a Cocaine and amphetamines
11.11.4a
Detoxification
11.11.5a Drug dependence
11.11.6a Drugs and medications
11.11.7a Harm reduction
11.11.8a Mode of action of drugs
11.11.9a Therapeutic index
11.11.10a Types of drug use
11.11.0 Introduction
11.11.1a
Addiction
This term refers to people with a pattern of behaviour that make
their lives become unmanageable, e.g. addiction to alcohol and drugs.
Addiction involves a strong desire to engage in
the particular behaviour, impaired capacity to control the behaviour,
distress when the behaviour is prevented, and
persistence with the behaviour despite evidence that it leads
to problems. People with an addiction need to face the reality of the
situation and
to have some positive experiences to regain self-esteem and
hope. They must attempt to find a new set of values or personal
orientation to achieve successful control and cure.
11.11.2a
Classification of drugs
Drugs can be classified based on the effects they have on the central
nervous system. Some drugs can fall into more than one of
these categories. For example, cannabis can be classed as a depressant,
but in sufficient doses it can also act as a hallucinogen.
1. Analgesics, "painkillers" ereliev pain at the source of the pain or
along the central nervous system. These drugs include opiates, e.g.
morphine, codeine, aspirin, ibuprofen, "Tylenol".
2. Anticonvulsants inhibit the spread of cortical stimulation, e.g.
"Dilantin", hypnotic sedatives.
3. Hallucinogens, psychotropics, "mood changers" can alter perceptions
and
sense of time and space. These
drugs include ketamine, LSD, magic mushrooms, cannabis, antipsychotics
e.g. chlorpromazine, cocaine, antidepressants, e.g. imipramine, mood
stabilizers, e.g. lithium, anti-anxiety drugs, e.g. "Valium",
"Librium", alcohol, kava, St. John's wort.
4. Sedatives, hypnotics ("downers") depressants, suppress or decrease
the activity of the central nervous
system. These drugs may increase sleep, lessen anxiety, create calm.
These drugs include alcohol, cannabis, sedatives,
tranquillizers, barbiturates, e.g. phenobarbital, "Nembutal", amytal,
benzodiazepines, e.g. "Librium", "Valium", sleeping pills and
opioid
drugs, e.g. heroin,
methadone, "Benadryl".
5.
Stimulants increase the activity of the central nervous system. They
are addictive and may affect the cardiovascular system. These drugs
include amphetamines, ecstasy, cocaine, nicotine, xanthines, e.g.
caffeine, "diet pills", "Sudafed", "Actifed".
11.11.3a Cocaine and
amphetamines
These drugs belong to a group of drugs that mimic the natural
substances that
stimulate the central nervous system (CNS). They cause an elevation of
mood, a sense of
increased strength and mental capacity, and less need for sleep or
food. The people living high in the Andes chewed the leaves of
the
coca bush for generations for just this purpose. The cocaine is
converted from the hydrochloride salt to the free base with
alkali and
extraction with organic solvents. Absorption from the lungs is
then
increased dramatically. The drug is highly addictive.
11.11.4a
Detoxification
This term refers to the means by which the drug-dependent person may
withdraw from the effects of that drug in a supervised way.
11.11.5a Drug
dependence
This term describes the pattern of behaviour shown by drug
dependent users and the physical changes experienced by them.
Drug-related disabilities
This term includes harm suffered through changed
behaviour because of the intoxicating effects of the drug, dependent
use of
the drug, poor nutrition and poor hygiene, impurities or contaminants
in the drug used and harm from diseases contracted because of lack of
health care, e.g. HIV/AIDS.
11.11.6a Drugs and
medications
To avoid
confusion between "medication" and widely prohibited "drugs" such as
cocaine, heroin and other substances, distinguishing it between these
two words is advisable. Drugs administered by medical
prescription should be called "medications". Drugs can be
classified as
analgesics (pain deadening) sedatives and
tranquillizers (reduce anxiety) stimulants, anti-depressants,
hallucinogens.
A drug is any chemical that changes the mental state and that may be
used repeatedly for that effect by a person. Drugs may adversely affect
the health of the individual and the social surroundings. "Drug" refers
to alcohol, tobacco, psychoactive drugs (amphetamines, ecstasy)
illicit drugs (heroin, cannabis, cocaine C17H21ON4)
volatile substances (petrol,
some fluorocarbons) and anabolic steroids.
11.11.7a Harm reduction
This term refers to the new approach being taken to all drug-related
problems. The aim of any intervention is not so much stopping drug use
but focussing on the reduction of specific drug-related harm. Harm
reduction for
injecting drug users primarily aims to help them to avoid the
negative health consequences of drug injection and improve their health
and social status. To this end, harm reduction approaches
recognize that for many drug users, total abstinence from
psychoactive substances is not a feasible option in the short
term, and aim to help drug users reduce their injection frequency
and increase injection safety. The following are components
that typically have a significant potential to reduce individual
risk behaviours associated with drug injection:
1. Needle-syringe programmes (NSP) aim to ensure
that those drug users who continue injecting have access to clean
injection paraphernalia, including needles and syringes,
filters, cookers, drug containers and mixing water.
2. Drug substitution therapy (DST) involves the medically
supervised treatment of individuals with opiate dependency based
on the prescription of opiate agonists such as methadone.
3. HIV-related treatment and care primarily aims to help
drug users living with HIV and AIDS cope with their
infection.
11.11.8a Mode of
action of drugs
The effect of drugs is strongly influenced by the personal and social
environment. Traditional drugs used in traditional ways often cause few
problems. Opium and cocaine are good examples. In a different legal and
social climate their effects can be disastrous. Opiates reduce pain,
aggression and sexual drive.
11.11.9a Therapeutic
index
This term refers to the ratio of the toxic dose to the effective
dose. The larger the index the safer the use of the drug
11.11.10a Types of
drug use
1. Social and recreational use for enhancing social
interaction or the enjoyment of some leisure activity.
2. Symptomatic use for reducing unpleasant sensations or
experiences or to avoid challenging situations or responsibilities.
3. Dependent use so that other responsibilities are neglected and harm
may result. Such dependent use becomes habitual. Abstinence may be
associated with the onset of withdrawal symptoms and the discomfort of
withdrawal will become a motivator for renewed drug use.
11.11.1b Reasons
students may give for trying
drugs and what the teacher can say in reply
1. “Someone had some and I thought I'd try it."
Dress your concern and question their decision. Ask whether it was what
they expected talk about the risks of further use. Try and find out if
they felt pressured. This may lead to better ways for them to handle a
similar situation in the future. Consider using examples of times when
you have had to deal with similar situations.
2. “I always wanted to try that stuff."
As what made that particular drug appealing, and what they expected to
get from it. Questions such as "What did you think it would be like?"
and "Why that drug?" may be worthwhile. You may be able to discuss
whether they have tried other drugs and if so, why. Say that you're
concerned with their behaviour and try to establish some ground rules.
3. "All my friends were doing it so I thought . . . why
not?"
Make your feelings about drug use clear and explain why you don't want
them to use drugs. Ask if they felt it was safe because their friends
were using it. Ask why they thought their friends used it and whether
they were aware of the risks. Discuss the dangers of experimenting with
drugs. Discussing the importance of being able to make their own
responsible decisions may be useful instead of following the crowd.
4. “It made me feel really good."
Try exploring the main reason the young person took the drug. Find out
how they have been feeling. This is a good time to offer help and to
find out if you can do anything for them or if they want to talk about
another issue. Talk about less risky way of feeling good.
11. "All my problems from school, home and life just went away.”
This statement is a chance to really confront other issues. You can
express your concern about students who use drugs for coping. Let them
know that if there are problems, you would like to talk about them. Ask
what can be done to make things better. Discuss whether the
problems
returned after the effects of the drug wore off. Express your feelings
about the dangers of using drugs to deal with problems. Make it clear
that you want to work together to find a better way of solving their
problems.
6. “It gave me more confidence."
Let them know that this is of concern to you and explain that they
don't need drugs to feel good about themselves. Share your own
experiences where you also found it difficult in social
situations
and explain ways that helped you gain more confidence. These can
be
both positive and negative experiences. By acknowledging your own
behaviour, you will increase your credibility with the young person.
Consider ways in which you can help to improve the student’s
confidence and self-esteem.
11.11.01 Abuse of
volatile substances, inhalants
Product: Inhalants can include general household and office products,
e.g. solvents, aerosols, glue, petrol.
Street name:
Nitrous oxide: laughing gas, whippits, nitrous.
Amyl nitrate: snappers, poppers, pearlers, rushamines.
Butyl nitrate: locker room, bolt, bullet, rush, climax, red gold.
Symptoms: Slurred speech, impaired coordination, nausea, vomiting,
slowed breathing, euphoria.
Potential problems: Brain damage, paralysis, pains in the chest,
muscles, joints, heart trouble, severe depression, fatigue, loss of
appetite, bronchial spasms, sores on nose or mouth, nosebleeds,
diarrhoea, bizarre or reckless behaviour, suffocation, sudden death.
A volatile substance is not a drug but misuse of them cause similar
problems to misuse of drugs A volatile substance is a compound that
gives off a vapour or fumes at room temperature. The recreational
sniffing of gases and solvents has become relatively common,
particularly among adolescents in Australia, with the mean age of
solvent abusers being 12 to 15 years. Volatile substances include
petroleum fuels,
propellants from aerosol products, chlorinated hydrocarbons, glue, nail
polish remover, antifreeze, paint thinners and anaesthetic products.
All of these substances are fat soluble and are stored in the fat
deposits within the body, particularly in the brain. This leads to a
prolonged effect on the level of consciousness even hours after the
inhalation has stopped. This is an extremely dangerous practice and
sudden death may occur even during the first usage. Substances are
generally placed into a plastic bag, or another vessel, and placed
directly over the nose and mouth and inhaled deeply. The effect of
substances inhaled in this manner produces alterations in the level of
consciousness including a pleasurable feeling of intoxication and
visual hallucinations. The most important problem of volatile solvent
use is the occurrence of potentially fatal cardiac arrhythmia because
of
intoxication. Respiratory depression can also occur. Although there are
doubts about physical addiction, psychological dependence is common.
Behavioural indicators of
use include persistent truancy from school, unruly behaviour, lack of
attention in the classroom, frequent use of handkerchiefs, continual
sniffing or sucking of shirt sleeves or jacket sleeves, change in sleep
pattern, truculent moody behaviour, difficult communication with
parents or teachers. The effects of a single use, while potentially
very dangerous, usually wear off after a few hours and the
cardiovascular symptoms predominate. Other symptoms include chronic or
frequent cough, tinnitus, chest pain or angina, nosebleeds, extreme
tiredness or weakness, increased nasal secretions, red, watery eyes, a
dreamlike state with hallucinations, depression and / or anxiety. The
effects of inhalation are immediate, lasting from 5 to 45 minutes after
cessation of sniffing. While initial effects may fade after several
minutes, depending on the method of inhalation, effects may be felt for
several hours. For most users effects will pass within an hour of
ceasing inhalation of the volatile substance. Chronic users may
experience withdrawal symptoms similar to those experienced from a
general anaesthetic. Hangover effects may persist for several days, and
may be characterized by tremor, headache, nausea, vomiting and
delirium.
Most users of volatile substances are young adolescents, 12 to 15
years.
In some groups there is predominantly chronic or dependent use, e.g.
among Aboriginal youths, i.e. between the ages of 15 and 24 years.
Sometimes, the use of computer games to stimulate recreational activity
has been found useful in
those young people who are seeking and achieving abstinence from
solvents. A video role play approach has been helpful
by using the role play in discussions involving resolution of crisis
and difficulties in relationships with parents or other members of the
family. These films can be used in the education of other abusers of
volatile substances.
11.11.1 Chroming, "huffing"
"Chroming" refers to sniffing aerosol spray paint can fumes usually
from plastic bags or drink bottles. The term comes from the lead
chromate in silver gold and bronze coloured paint that have a high
concentration of toxic compounds that can get you "high". Other
inhalants used for chroming are typewriter correction fluid, "White
Out" or "Liquid Paper" thinner and model aircraft cement. The drunken
dizzy feeling induced is often accompanied by excitability, euphoria,
decreased inhibitions, delusions of grandeur, and reckless behaviour.
Long-term use can lead to permanent damage to major organs, depression
and anxiety disorders, and dependence. Some addicts become suffocated
by the plastic bags used. Medical evidence suggests damage done to
hyopcampal
stem cells in the brain causes memory impairment and to cerebral cortex
cells causes personality changes, hallucinations and memory
impairment. However, one report suggests that it very difficult to find
a link between chroming and hallucinations.
11.11.2 Petrol-sniffing
Petrol sniffing is a
common practice among the youth of poor Aboriginal
settlements in the
Australian outback. Besides damage because of inhalation of the
volatile
components of petrol, lead poisoning may occur even from "unleaded
petrol" because it still contains a small amount of lead that may be
accumulated in body fat by persistent sniffing. However, the
petroleum company BP has produced a new form of gasoline
called "Opal" that does not contain lead and contains only a very low
level of the aromatic hydrocarbons that give petrol sniffers their
"high". The substitution of Opal for normal petrol has been a very
effective way to stop petrol-sniffing.
11.11.3 Alcohol abuse
No specific level or pattern of drinking alcohol should be considered
safe. It has been agreed from available evidence that a
range of drinking that most people would consider low risk and
drinking that is considered hazardous, dangerous or dysfunctional, can
be defined.
Low risk drinking
Female: Never more than two standard drinks in a day (except for
pregnancy)
Male: Never more than four standard drinks in a day
(1 standard drink = 10 grams of alcohol)
Hazardous drinking refers to drinking that raises the blood alcohol
level (BAL) above 50 mg alcohol/100 mL blood (0.05%)
Clinical signs and symptoms of possible hazardous alcohol use include:
morning nausea and vomiting, dyspepsia, recurrent diarrhoea,
hypertension, palpitations, anxiety, hand tremor, financial
difficulties, depression in spouse or family members. Dysfunctional
drinking is drinking that has already led to psychological
damage or to impairment of social functioning, including disturbance of
marital or family relationships, drink driving or other convictions,
impaired job efficiency.
National health and medical research council recommendations: In 1992
the National Health and Medical Research Council published a series of
recommendations about responsible drinking behaviour.
That the idea of a standard drink, or unit, containing 8-10 grams of
absolute alcohol be adopted for clinical and educational
purposes. That the following guidelines be promoted as consistent with
responsible drinking: that the consumption of alcohol by men should not
exceed 4 units or 40 grams of absolute alcohol per day on a regular
basis, that the consumption of alcohol by women should not exceed 2
units per day or 14 units per week on a regular basis that 2-4 units
per day or 14-28 units per week be considered hazardous and that more
than 4 units per day or 28 per week be considered harmful. Caucasians
oxidize ethanol slowly to acetaldehyde then further oxidation to acetic
acid occurs. So they tend to become drunk because the alcohol stays
unchanged in the body. Northern Chinese and Japanese may oxidize the
alcohol more quickly causing red cheeks and unpleasant sensations from
the sudden increase of acetaldehyde in he blood. Eventually the alcohol
is metabolized by the slow acting alcohol dehydrogenase enzyme in the
liver assisted by the extra-enzyme cytochrome mono-oxygenase in heavy
drinkers. Alcohol dehydrogenase converts alcohol in the liver to
acetaldehyde.
Fast acetylators can be embarrassed by the flushing that occurs after
drinking alcohol because of the sudden release of acetaldehyde. The
further oxidation to acetic acid occurs at the same rate in both fast
and slow acetylators.
11.11.4 Amphetamines, amphetamine, epinephrine
(adrenaline) amphetamine-type stimulants, ecstasy, "speed", "base", ice
Amphetamine-type stimulants are synthetic drugs which means they are
made by combining various chemical ingredients rather than occurring
naturally
Amphetamines are a family of drugs that include methamphetamine. These
drugs are similar in their chemical make-up and affect the messages
going to the body's central nervous system. Currently, methamphetamines
are more common in Australia than other amphetamines. These types of
drugs are sold in different forms such as powder, paste, liquid, pills
and crystals. The potency of these forms varies, with the most potent
being the crystalline form, typically called Ice or Crystal Meth.
Ecstasy, MDMA, 3,4-methylenedioxymethamphetamine, is also an
amphetamine-type stimulant and mild psychedelic because it has a
chemical
structure that is similar to amphetamines. The effects of ecstasy are
different from amphetamines and can bring on some effects more
typically found in hallucinogenic substances. Ecstasy pills contain
about 40 mg of MDMA but powder is also available. Research show that
consistent users of this drug experience slight memory difficulties and
mild depression but some people have more severe symptoms. The short
term effects for a small fraction of users my include severe
overheating or water intoxication leading to death. The drug may cause
long-term damage to the serotonin system.
Amphetamine / methamphetamine
Speed, base and ice are currently the most common street names for
these types of drugs. They share the same symptoms and potential
consequences but can differ in severity.
Designer drugs
1. The psychoactive compounds, phenylethylamines
(mescaline analogues), e.g. catecholamines, amphetamine,
methamphetamine, 3,4-methylenedioxyamphetamine (MDA -ecstasy) and
3,4-methylenedioxymethamphetamine (MDMA)
Amphetamine overdose may cause tachycardia, hypertension, hyperthermia,
diaphoresis, mydriasis, agitation, muscle rigidity, and hyper-reflexia.
Death usually results from arrhythmias, hyperthermia or intracerebral
haemorrhage.
2. Synthetic opioid derivatives, derivatives of fentanyl (e.g.
alpha-methylfentanyl, 3-methylfentanyl) or pethidine (meperidine)
3. Arylhexylamines, e.g. phencyclidine (PCP) a derivative of the
anaesthetic ketamine.
11.11.4.1 "Speed" and "base"
Product: Methamphetamine hydrochloride, amphetamine sulfate (grey,
dirty-white, pinkish powder,
paste, liquid and pills).
Street name: Speed, whiz, go-ee, zip, oxblood, dexy's midnight runners,
phets, meth, base, glass, uppers, whizz, billy, sulph. base, paste,
pure, gas, amphets.
Symptoms: Common responses to intoxication include euphoria, increased
blood pressure and pulse rates, increased and irregular breathing and
heartbeat, insomnia, loss of appetite and dilated pupils, confidence,
increased energy, talkativeness and excitability
These drugs can cause anxiety, restlessness, sweating, overheating,
blurred vision, nausea and diarrhoea, jaw clenching and / or teeth
grinding.
Potential problems: Sleep problems, dental problems (e.g. cracked teeth
through grinding) weight loss, stroke or heart problems, high risk of
dependence. Injecting the drug is also associated with a risk of
contracting blood-borne viruses, like hepatitis C and HIV
Problems with attention and memory, paranoia and paranoid delusions,
anxiety, panic attacks, hallucinations, depression, mood swings,
aggression, violence, social and financial problems, compulsive
repetition of actions, family arguments and conflict, the risk of
family breakdown and losing friends.
Speed is the street name for amphetamine and a range of amphetamines.
Amphetamine is similar to norepinephrine, the "fright hormone" that
causes the response to sudden stress or excitement. The pharmaceutical
classes of amphetamine include laevo or dl-amphetamine ("Benzedrine")
dextroamphetamine ("Dexedrine") and methylamphetamine ("Methedrine")
called "crystal meth". Speed is usually amphetamine sulfate that
contains equal amounts of laevo-amphetamine and dextroamphetamine. A
"speedbomb" is speed wrapped in cigarette paper to form a pill which
when swallowed may cause stomach pains, inflammation and ulcers. Speed
may be "cut" (diluted) with milk powder, paracetamol and other white
powders but the pink-grey "base speed" is usually more pure. People
take speed because it gives them a feeling of awareness and excitement,
they get "high". In night clubs people take it to help them to
dance all night. Formerly, amphetamines were prescribed by
doctors for overweight patients because amphetamines reduce appetite.
Injected speed produces and quicker and longer "high" then a slow
"comedown".
11.11.4.2 Ice
Ice generally looks like colourless crystals or crystalline powder. The
difference between Ice and Speed / Base is the way it is made.
The
chemicals are the same but Ice is a highly potent drug that increases
the severity of the potential consequences.
Product: Crystal methamphetamine hydrochloride
Street name: Ice, meth, crystal, crystal meth, sabu, batu, d-meth,
tina, glass.
Other potential problems: In the short term, Ice can produce increased
heart rate, hypertension, irregular body temperature, increase
breathing rates, constrict blood vessels, and cause heart problems.
Longer-term users of the drug can typically appear older than their age
and may have damaged teeth, skin lesions, and greater risk of strike,
decreased lung function and poorer cognitive function.
Ice users are at risk of experiencing a drug-induced psychosis, they
can become paranoid and hallucinate. A person can become increasingly
aggressive and have violent behaviour possibly requiring chemical
and physical restraint or police intervention.
There is a high risk of addiction, including through smoking. Damage
can occur to lungs through smoking Ice and to the lining of the nose
through snorting. If injected it can lead to scarring, abscesses and
vein damage.
The Queensland Department of Health reports that ingesting ice can
cause addiction, emergency psychiatric care, violence, aggression,
hallucinations, paranoia, anxiety, panic, depression, bizarre beliefs,
and compulsive behaviour.
11.11.4.3 Ecstasy
Product: MDMA (Methylenedioxymethamphetamine)
(3,4-methylenedioxy-N-methylamphetamine)
Street name: Adam, E, Ex, E and C, eccy, Ecstasy, eggs, Essence, love
drug, MDMA, PMA, XTC
Symptoms: Increased blood pressure and pulse rates, sweating,
overheating, jaw clenching, teeth grinding, nausea, anxiety,
excitability, tremors, insomnia, enlarged pupils, loss of appetite.
Potential problems: Sleep problems, cracked teeth through grinding,
high blood pressure, dehydration, nervousness, hallucinations, memory
and attention impairment, decreased emotional control, lethargy, severe
depression, possible nerve cell damage, thermal meltdown, death from
heart failure.
Amphetamines were once used to treat
obesity, mild depression and
narcolepsy (a tendency to fall asleep at any time) and certain
behavioural disorders in children. Amphetamines are pep pills.
Ordinary doses of 10 to 30 mg per day provide a feeling of
well being
and increased alertness. Amphetamines are structurally similar to
the
naturally occurring biogenic amines, such as ephedrine, which act
as stimulants of the central nervous system, in a similar manner
to epinephrine.
Amphetamine and epinephrine are optically active, i.e. two compounds
with the same formula with structures mirror images of each other and
cannot be superimposed. You cannot
place one hand in an identical position on top of the other. However,
if you hold them parallel. One hand is as the mirror image of the
other.
A pair of chemicals related in this way are called left-handed,
l, and right-handed, d. Compounds differing only in this way can
be
biologically very different in their activity. Benzedrine is a
50: 50
mixture (racemic) of the l-amphetamine and d-amphetamine but while the
l-form is less active on the central nervous system, the pure d-form,
dexedrine, is nearly twice as potent.
Amphetamines and barbiturates were often used in conjunction. Thus
amphetamines may be consumed in the morning to alleviate the symptoms
of a barbiturate hangover, while the barbiturates may be necessary to
counteract the stimulant properties of amphetamines and allow the user
to sleep. In case of overdose they were also used as mutual antidotes.
The deeply held belief by the public in antidotes is somewhat
dangerous, because although two substances may be antidote in one
aspect, they can reinforce each other (synergism) in other side
effects.
The death rate can be very high. The amphetamines also form a family of
drugs although the pattern is somewhat difficult to see and tends to
overlap other categories of drugs.
In Australia amphetamines have been used to treat some medical
conditions however these drugs are both potentially addictive and quite
toxic. The best known members of this group of stimulants are
dexamphetamine (e.g. dexedrine) methamphetamine (e.g. methedrine) and
the amphetamines (e.g. benzedrine). Amphetamines are simple amines with
many effects including cardiovascular and central nervous system
stimulant actions which is similar to the naturally occurring hormone
adrenaline. They stimulate and excite all areas of the nervous system,
including the brain. As they inhibit sleep and fatigue, the main
concern is the self-medication of amphetamines by truck drivers,
students and businessmen, who use amphetamines to stave off normal
fatigue and enable them to work for days with little sleep or food.
Young people who frequent night clubs use amphetamines so they can
dance all night. Truck drivers use amphetamines so they can drive for
long periods without rest and make more trips per week.
The drug has a reputation of facilitating social and sexual
interactions:
1. Implications for HIV transmission, i.e. if enhanced sexuality is
not accompanied by safer sexual practices.
2. Amphetamines are often used in a casual fashion accompanied by
alcohol. The setting is not conducive to the use of clean needles and
amphetamine use is an independent risk factor for HIV infection.
Injecting drug users are increasingly emerging as a poly drug-abusing
group and as amphetamines are cheaper than heroin on the street more
IDUs are including amphetamines in their repertoire of drug use.
Immediate effects at low doses include sensations of euphoria, enhanced
self-awareness and self-confidence, increased visual awareness,
heightened alertness, increased capacity for concentration, greater
energy. Users become hyperactive, talkative, excited, irritable and
restless. Effects at high doses include dry mouth, fever, sweating,
headache, blurred vision, rapid or slurred speech and collapse.
Long-term effects include malnutrition, since amphetamines suppress
appetite, and sudden acts of aggression. Multiple drug uses may take
depressant drugs such as alcohol and barbiturates in combination to
fight the side effects of amphetamine use, such as sleeplessness.
Prolonged use may lead to drug dependence.
Methamphetamine (methylamphetamine desoxyephedrine) is highly addictive
and is becoming widely used in many countries.
11.11.5 Antihistamines,
histamine, dexchlorpheniramine (Polaramine), allergy
Many people are allergic to pollen, stings, and
dust. An allergen is a
substance that initiates the allergic response. It is usually a protein
but is sometimes a polysaccharide. For a person with pollen allergy, a
pollen grain enters the nose and clings to the mucous membrane. The
nasal secretions acting on the pollen grain release the grain's
allergens and other soluble components, which penetrate the outer layer
of the mucous membrane. By a series of events that are not well
understood, the allergen forms a complex with an antibody of a type
that is present in unusually high concentrations in allergic persons.
The complex is responsible for the release of the allergy mediators,
one of the most potent being histamine. Histamine is formed by the
breakdown of the amino acid histidine. It accounts for many
symptoms of hay fever and other allergies.
Antihistamines are most widely used for treating allergies, and there
are more than 50 types available. Like histamine, many contain an
ethylamine group, -CH2CH2N =. These
drugs compete with
histamine for the receptor sites normally occupied by it on cells and
thus prevent it from causing allergic reactions. An example of a
well known antihistamine is Polaramine. Some tricyclic
antidepressants have antihistamine effects as well, because they also
contain the ethylamine group.
11.11.5.1 Skin-prick
tests for allergy
Put a drop of the solution containing the suspected allergen on the
person's forearm. prick the skin under the drop with a sterilized
needle. Any itchiness, reddening of the skin or white swelling
indicates an allergy to the suspected allergen.
11.11.6
Aspirin
and analgesics, paracetamol, acetaminophen (Panadol,
Tylenol)
Both
salicylic acid and acetylsalicylic acid
(aspirin) can breach the
protective barrier in the stomach and cause stomach bleeding. For most
people the bleeding produced is trivial however, including children, it
can be hundreds of millilitres and require emergency hospitalization.
In acid solution aspirin is not ionized and is fat-soluble and can
diffuse through the stomach's protective barrier. Once through, it is
in
a neutral environment where ionizes and then cannot pass back again.
The
rate of diffusion is enhanced by alcohol even when the contents of the
stomach have a low acidity. Such cooperative action may be called
synergism. Aspirin has the effect of slowing the release of the
prostaglandins that promote inflammation and stimulate pain receptors.
The related methyl salicylate, oil of wintergreen, is used
externally
to ease the pain from rheumatism and strained muscles. Aspirin kept too
long begins to hydrolyse to salicylic acid, which is not well
tolerated by the human body. Soluble aspirin is either the sodium or
the calcium salt of normal aspirin. These salts immediately form
aspirin in the acid stomach as fine crystals and possibly
cause less gastric distress. Some analgesics, e.g. Panadol, contain
p-acetylaminophenol (4-hydroxyacetanilide, paracetamol) which is
comparable to aspirin as a pain reliever but is gentler to the stomach.
11.11.7
Barbiturates,
phenobarbital, amylobarbital, pentobarbital,
thiopenta
See: Barbiturates 16.3.4.0.5a
Previously, barbiturates were the major
ingredients used in
sleeping
pills and provided adjuncts to anaesthetics. Phenobarbital has
distinctive anticonvulsant properties useful in the treatment of
epilepsy. Barbiturates are derivatives of barbituric acid that is not
pharmacologically active. Replacement of the hydrogen atoms at
the
fifth carbon position with alkyl or aryl substituents yields
drugs
with sedative or hypnotic properties. More than 2000 barbiturates have
been synthesized but only a few have become widely adopted in
medicine. Thiopental is the standard injectable general anaesthetic.
The chain length of the substituents at the C-5 position affect the
action of a particular barbiturate, e.g. phenyl group or alkyl
group
for anticonvulsant activity. However, convulsants are produced if
the
chain is too long or if alkyl groups are placed on the two nitrogen
atoms at positions one and three. If thiourea, CH4N2S,
is used
in place of urea in the synthesizing reaction, thiobarbiturates are
obtained, e.g. thiopental. The more fat soluble the barbiturate
with
non-polar groups, the more rapid the onset of the action. Hypnotic
properties may often be increased by increasing fat solubility and may
be abolished by introducing polar groups on the side chains.
Barbiturates and alcohol are both metabolized in the liver and even
when each is at a non-toxic dosage, the combination can be toxic
because the alcohol retards the excretion of the barbiturate. When
hypnotics are first taken, they may reduce dreaming and interrupt sleep.
11.11.8 Classification
of barbiturates according to action time:
(The names in
parentheses are trade names.)
1. Long-acting: phenobarbital, methylphenobarbital
(Prominalb)
2. Intermediate: amylobarbital (Amytal)
butobarbital (Sonabarb) butethal (Neonal) hexethal (Oral)
vinbarbital (Delvinal)
3. Short-acting: cyclobarbital (Amnosed)
pentobarbital (Nembutal, Petab, Sommital, Penbon, Sodepent,
Pentone,
Pentobeta) secobarbital (Seconal)
4. Ultrashort-acting: hexobarbital
sodium (Evipal) thiamylal sodium (Surital) thiopentonesodium
(Pentothal)
11. The thiobarbiturates (Pentothal and
Surital) are inactive by mouth and can be administered only by
intravenous or rectal routes. They belong to the group of infamous
truth
drugs. Both tolerance (increasing quantities needed for an effect) and
physical dependence occur with high doses. The barbiturates stimulate
enzymes in the liver that breakdowns the drug, thus reducing its
effect. Although tolerance develops to the sedative effect of the
drugs, the lethal dose remains essentially constant. As tolerance
increases, therefore, the margin of safety decreases, and accidental
poisoning may occur at doses that no longer provide sedation.
6. The
therapeutic index is the ratio of the toxic dose to the effective dose.
The larger this factor is, the greater the safety in the use of the
drug. The therapeutic index is dependent on two types of drug
tolerance:
6.1 Pharmokinetic tolerance to changes in the
concentration of the drug in the body caused by changes in
liver activity
6.2 Pharmodynamic tolerance caused by the
receptor (where the drug acts) requiring more drug while the
concentration for receptor poisoning may not change.
11.11.9 Hallucinogenic drugs, hallucinogens
mescaline,
psilocybin, scopolamine
(hyoscine) atropine, LSD, tryptamine, cocaine, THC cannabis
Product: LSD (lysergic acid dliethylamide) Psilocybin.
Street name: LSD, acid, trips, wedges, windowpane, blotter, microdot
Psilocybin: mushies, blue meanies, magic mushrooms, gold tops, datura,
angel's trumpet.
Symptoms: Trance-like state, excitation, euphoria, increased pulse
rates, insomnia, hallucinations, paranoia.
Potential problems: visual hallucinations may produce anxiety and fear,
confusion and lack of coordination can result in greater risk of
injury, self-inflicted injury, violent behaviour, paranoia, depression,
anxiety, unpredictable flashbacks.
Hallucinogenic (or related psychotomimetic)
drugs derived from various
plants and fungi have been used from ancient times. The use of the
emetic toadstool Amanita muscaria
extends over thousands of years. The
Aztec and Mayan cultures used the peyote cactus, from which mescaline
is derived. They also used the psilocybe mushroom (or sacred mushroom
Teonanacatl) the active principle of which is psilocybin, which is
about 30 times as potent as mescaline. From Ipomea (morning
glory)
the Mexican Indians obtained a substance similar to lysergic acid, and
from the plant Datura stramonium (thorn apple) they obtained
scopolamine (hyoscine) and atropine. Other plants used in Central and
South America contained cocaine. Tannin in tea contains gallic acid,
which can be converted to mescaline by complex
Mescaline is classed as a catecholamine, along with amphetamines, to
which it is structurally related.
Lysergic acid diethylamide (LSD) is classed as an indoleamine. It
is
one of the most potent drugs known. Very low doses are capable
of causing marked
effects in susceptible individuals. Lysergide was discovered while
investigating a modified ergotamine as
an improved drug for childbirth. Ergot itself is found on many plants,
particularly rye. An ergot alkaloid is used to induce uterine
contractions. In ergotamine, the diethylamino group is replaced by a
peptide.
The opiate alkaloid oxycodone, "hillbilly heroin", made from thebaine,
has unique stimulating properties is
usually supplied as oxycodone hydrochloride.
11.11.10 Cannabis
("pot", "marihuana" "marijuana", "Indian hemp", "hashish", "bhang")
Product: Marijuana, hashish, Cannabis sativa,
delta-9-tetrahydrocannabinol.
Street names: Pot, grass, weed, reefer, joint, Mary-Jane, Acapulco
Gold,
rope, mull, cone, spliff, dope, skunk, bhang, ganja, hash, chronic,
yarndi.
Symptoms: Difficulty concentrating, slow reflexes, impaired motor
skills, reduced coordination and concentration, apathy, bloodshot or
glassy eyes, increased appetite, dryness of the mouth.
Potential problems: Mood swings, memory impairment, weight gain,
chronic bronchitis, increased risk of cancer of the lung, mouth, throat
and tongue, panic attacks, anxiety, depression, paranoid thinking,
decreased motivation, interference with reproductive function, learning
difficulties, psychological dependence, suicidal thoughts, risk of
psychosis and psychotic symptoms. Cannabis serves as barrier against
self-awareness, and may interfere with a young person's development
including possible interference with reproductive function.
The most active ingredient in the extract is tetrahydrocannabinol, THC,
obtained from the fruiting or flowering tops of the cannabis plant.
There are many ingredients in cannabis other than THQ and their
long-term effects are unknown. Recent analysis of samples of
purchased marihuana indicates an average of 10%
tetrahydrocannabinol, about double the average concentration 25 years
ago when marihuana was commonly called "grass".
Cannabis is the psychotropic product from the plant Cannabis sativa
which is one of mankind's oldest cultivated plants. It is used for its
fibrous qualities (hemp) as well as its medicinal properties because of
compounds called cannabinoids. The major active ingredient is the
cannabinoid "D9 tetrahydrocannabinol" or "THC". It is fat-soluble, so
it may remain in the body tissues such as the brain for many days after
a single dose.
If cannabis is smoked a "high feeling" is attained much more quickly
but if eaten the effects are long lasting. Additive effects are
observed with alcohol and other CNS depressants, but no clear
interaction has been noted with stimulants. The effects of cannabis
include feelings of self-confidence, euphoria, well being and
relaxation, altered perception of time and space, heightened
perceptions of taste, smell, touch, and hearing, delusions and
hallucinations. The main at risk groups are young people with friends
who are illicit drug users. Recurrent use may lead to impaired
fertility. In males, cannabis use diminishes testosterone production
and decreases sperm count. It also results in abnormal shape and
chemical composition of the sperm cells. In females, cannabis can
affect fertility by disrupting the reproductive cycle through changes
to ovulation and menstrual cycles. Another concern is the possibility
of foetal damage during pregnancy. In the long-term may result in
impotence, loss of normal sex drive and infertility. Heavy cannabis use
produces a change in personality and in behaviour that is more
dramatically shown by children and adolescents than it is by
adults. Some adolescents who use cannabis have been observed to be
devoid of the drive and energy normally seen in adolescents. Cannabis
is known to be both mutagenic and carcinogenic as well as destructive
to lung tissue. Since cannabis smoke is inhaled deeply, held for much
longer and contains more tar than tobacco, the adverse effects are
greater. As a result, smoking 2-3 cannabis cigarettes may carry the
same risk of lung damage as smoking a whole packet of tobacco
cigarettes. Use of cannabis may lead to use of "hard" drugs and to drug
dependence.
11.11.11 Cocaine and crack cocaine
Product: Cocaine, crack cocaine
Street names
Cocaine: coke, flake, snow, happy dust, Charlie, gold dust, Cecil, C,
freebase, toot, white girl, Scotty, white lady.
Crack cocaine: crack, rock, base, sugar block.
Symptoms: Anxiety, agitation, increased pulse rates, enlarged pupils,
paranoia, hallucinations, excitability, euphoria, talkativeness.
Potential problems: High risk of addiction, erratic behaviour,
hallucinations, cocaine psychosis, eating or sleeping disorders,
impaired sexual performance, ongoing respiratory problems, ulceration
of the mucous membrane of the nose, collapse of the nasal septum,
cardiac arrest, convulsions.
Cocaine is an alkaloid of the coca shrub Erythroxylon coca. It
was
formerly used as a local anaesthetic for throat surgery. It is prepared
as a salt, cocaine hydrochloride. This salt can be inhaled
into the nostril or injected by intravenous injection. The cocaine salt
can also be converted to free base cocaine that is burned and the
smoke inhaled. Most cocaine users begin with intra-nasal administration
and later change to injecting use or inhalation of smoke. The free base
cocaine, "crack", sold in the streets of American cities is called
"crack". In USA, the cheap "crack cocaine" is used by lower
socio-economic groups, and expensive pure crystalline cocaine is used
by higher socio-economic groups. Cocaine is a highly addictive drug. It
produces feelings of increased confidence and exhilaration. High doses
cause loss of coordination, dizziness, hallucinations and violent or
aggressive behaviour, respiratory paralysis, and death. Unhygienic
injections of the drug can cause infections including hepatitis B,
hepatitis C and HIV/AIDS. As tolerance to cocaine develops rapidly,
social problems develop, e.g. debts, job loss, and impaired
productivity. Women have taken to
prostitution to support the cost of their cocaine addiction. Users may
mix cocaine use with other drugs, e.g. heroin, called "speedball",
to enhance effects. Withdrawal from cocaine is a slow and difficult
process requiring skilled medical management.
11.11.12 Ecstasy or
3,4-methylenedioxymethamphetamine (MDMA) is a
derivative of
amphetamine and has similar properties. It is used at dance parties and
other social venues. With increased use the negative aspects of use
tend to increase while the positive effects decrease, so few people
have dependence problems with it. The physical effects are teeth
grinding, restlessness, dry mouth, increased sweating, hot and cold
flushes. nausea and vomiting. Users experience a feeling of improved
personal relations, communication and intimacy, and euphoria. However,
this may lead to visual hallucinations, anxiety, loss of control and
panic. Users may suffer extreme dehydration and even death.
11.11.13 Designer drugs
A new wave of
designer has lead to death or permanent brain damage in Europe. Some
synthetic drugs, e.g. "Flatliner" (synthetic drug 4MTA) "Golden
Eagle", and "DOB" (death of body, "Nexus", "Spectrun", BZP,
N-benzylpiperazine) are
derivatives of Ecstasy but are known on the rave scene as "Super E"
because they are up to 30 times more powerful. "Flatliner" has been
blamed for deaths
in Britain. "Golden Eagle", an
amphetamine-based concoction, is powerfully hallucinogenic, causing
"trips" which last up to twenty hours. DOB is 10 to 20 times more
potent than
amphetamine. BZP tablets, especially those that also contain the
hallucinogen TFMPP (1-(3-trifluoromethylphenyl) piperazine) often are
sold as MDMA (3,4-methylenedioxymethamphetamine) are also called
ecstasy
or are promoted as an alternative to MDMA.
11.11.14 Morphine and
derivatives, codeine,
pethidine,
heroin, methadone, opioids
Product: Heroin, morphine, codeine, methadone, buprenorphine,
pethidine, Dilaudid, Kapanol, MS Contin.
Street name:
Heroin: horse, hammer, H, dope, smack, junk, gear, boy.
Morphine: M, Miss Emma, Mister Blue, morph.
Methadone: done.
Buprenorphine: Bupe.
Symptoms: Lethargy, drowsiness, nausea, constipation, constricted
pupils, slowed breathing.
Potential problems: High risk of addiction, mood swings, depression,
anxiety, chronic constipation, infection at sites of injection, HIV and
hepatitis infections through sharing of needles, non-fatal overdoses,
death from overdose.
Morphine was first isolated from the latex of the opium poppy, Papaver
somniferum. Another alkaloid, codeine, was isolated from opium.
Although codeine has only about one tenth of the potency of morphine,
its prolonged use in low doses can cause physical dependence. Morphine
was acetylated to produce diacetylmorphine or heroin, which is more
addictive than morphine. The first potent analgesic to be prepared that
did not depend upon
opium for its prime source was pethidine. The molecule can be drawn to
show the morphine structure. The first of the synthetic analgesics,
based on
3,3-diphenylpropylamine, was called methadone. The molecule can
be
drawn to show the morphine structure. The time of onset of physical
addiction of the opiates used to be
characterized as: heroin 4 to 5 days, morphine 1 week, pethidine 10
days to 2 weeks, methadone 1 month.
11.11.15 Heroin
Heroin is a drug derived from the opiate morphine. Opiates are a group
of
drugs derived from opium obtained from the poppy flower Papaver
somniferum. Heroin is safe and effective analgesic. It should be
used
only to prevent severe and persistent pain because it causes
dependence. Illegal use has produced much suffering and so
many people think of it as a "horror drug". The chemical is a white
crystalline powder that is soluble in water. The drug is administered
by injection or smoking. The onset of action is rapid and the duration
of action is 3 to 4 hours. The immediate effect or "rush"
after an intravenous (IV) dose is because of the high fat solubility of
the
drug and thus its rapid entry into the brain. The drug bought by
illegal users on the street results is a dose of variable amount
diluted by substances of varying quality and safety. Most
users inject their dose using solvents for the powder they
purchase. These solvents may be contaminated, e.g. lemon juice. Users
may be harmed by overdose resulting in a fatal cardiovascular collapse.
Most complications of heroin use relate to the injection of
contaminated material, or the use of non-sterile injecting equipment
that can cause septicaemia and transmission of HIV/AIDS and hepatitis
B disease. Methadone, a synthetic opiate, is used to treat heroin users
but
there are many arguments about using it. It replaces heroin and has a
longer life in the body than heroin. Drug users in a methadone
maintenance programme receive a single prescribed dose of
methadone
every
day. Methadone maintenance programmes are effective in reducing
the
frequency of injecting and the incidence of use of contaminated
injecting equipment. The Human
Immunodeficiency Virus (HIV) can be transmitted through the exchange of
HIV-infected body fluids from using HIV-infected injecting
equipment. Injection drug users should be warned about the risks of the
use of contaminated injecting equipment and taught needle and syringe
cleaning techniques or
the availability of clean needles and syringes or needle
exchange programmes in the area. They should use safer sexual practices
and use
condoms. New users are at special risk because their drug use is often
unplanned and thus they may share needles because they do not possess
the necessary equipment.
11.11.16 Nicotine, tobacco smoking and chewing
Tobacco comes from the leaf of Nicotiana tabacum. Tobacco smoke
contains carbon monoxide, nicotine, tars and poisonous chemicals, e.g.
turpentine, acetone, benzene and ammonia. Carbon monoxide is a
poisonous gas that is absorbed into the blood stream and temporarily
makes the heart work harder. Tars are poisonous chemicals that enter
the blood from the lungs and may cause many different cancers. Cancer
of the lung, mouth, throat, bladder and kidney are directly caused by
some 43 carcinogenic chemicals in tobacco smoke but nicotine
itself does not cause cancer. Nicotine is an addictive drug that
increases the blood pressure and heart rate. The nicotine content is
0.2% to
5%, i.e. 0.05 to 2.0 mg per cigarette. Nicotine is suspended in
particles of tar and is quickly absorbed in the lungs and reaches the
brain in about 8 seconds. Like cocaine and amphetamines, nicotine
releases dopamine to give good feeling and increase alertness. Nicotine
is both a stimulant and a sedative. It releases adrenaline and then
glucose and gives a temporary feeling of relaxation and well being.
However, this stimulation may be followed by depression and fatigue
leading to the person wanting more nicotine. The body of the smoker
becomes accustomed to the presence of nicotine and becomes
dependent on it. Withdrawal from nicotine for 24 hours may result in
anger, hostility, aggression and less social cooperation. Replacing
the nicotine in cigarettes with nicotine in chewing gum or skin patches
helps people to stop smoking and to quit smoking altogether. Stopping
access to nicotine abruptly may lead to depressed mood, difficulty in
sleeping, irritability, frustration, anger, anxiety, difficulty
concentration, decreasing heart rate and in creases appetite and weight
gain. Nicotine replacement allows smokers to control their craving for
smoking tobacco and avoid withdrawal symptoms. Nicotine can be
extracted from tobacco with supercritical solvents. A nicotine patch
applied to a clean dry site on the body may deliver up to 21 mg
nicotine per 24 hours through the hairless skin of the front or side of
the chest, upper arm, hip or upper thigh. Nicotine chewing gum may
include 4 mg or less of nicotine, saccharin / saccharin sodium and
flour, e.g. mint. The nicotine is absorbed through the mouth lining so
it should be chewed slowly. Nicotine inhalers allow flexible dosage and
the familiar hand to mouth action of smoking. An antidepressant tablet
to help quit smoking may be available on doctor's prescription. There
is great reduction in risk in people who stop smoking, even those
who stop at 50 or 60 years including less risk of heart attack, high
blood pressure, stroke, limb amputation and chronic respiratory
problems. Children of smokers are more likely to become smokers.
Passive smoking in the home increases the infant's risk of
pneumonia and bronchitis. Asthmatic children in a smoking households
have more frequent and severe asthma attacks. Male smokers are more
likely to be impotent and produce less sperm. Female smokers take
longer to conceive and are more likely to miscarry or have premature,
stillborn babies or babies dying from cot death.
Nicotiana tabacum, derives from the entrepreneur who
promoted its sale in France, Jean Nicot. The active ingredient is
nicotine. New
varieties, better methods of curing the leaf,
coupled with technology for mass production, allowed the introduction
in the mid nineteenth century of the cigarette. It was cheaper and
neater
than
the cigar, with a smoke so mild it could be inhaled. About 4000
compounds have been found in cigarette smoke. No other drug of
dependence causes cancer, and tobacco is the only environmental cause
of cancer that is on the increase.
Classification for health purposes
has concentrated on the levels of nicotine, tar (which contains the
potent carcinogens) and carbon monoxide. The carbon monoxide reacts
preferentially with the red corpuscles in the blood. On removal of the
source of carbon monoxide, the equilibrium with oxygen is gradually
restored.
The levels of these compounds are determined by using smoking
machines. However, smokers do not conform to smoking machines, and
manufacturers can design cigarettes to do well on the machines,
while dosing smokers at high levels. A common ploy is to include fine
holes just up from the filter, which lower the machine reading through
dilution of the smoke with air. However, when smoked for real, these
holes are covered by the smokers' lips.
The nicotine content of
tobaccos can vary from 0.2% to 5% and provides from 0.05 to 2.0 mg
(1982 average 1.0 mg) per cigarette to a smoking machine. In cigarettes
the nicotine is nearly always present in a protonated form in which it
is less readily absorbed through the mouth (hence the need to breathe
the smoke into the lungs) in contrast to the basic form found in
cigars and pipe tobaccos (smoke pH 8.5). The nicotine is suspended on
the minute
particles of tar and absorption from the lung occurs in seconds. Peak
concentrations found in
the blood are typically 25 to 50 mg / mL. When heavy smokers are
unknowingly given cigarettes with a higher content of nicotine they
subconsciously reduce the number smoked and alter their puffing pattern
to maintain about their usual level of nicotine. Conversely when given
low nicotine cigarettes they increase the number smoked and / or puff
more efficiently. If smoking low nicotine cigarettes, the smoker
then takes in more tar and more carbon monoxide for the same level of
nicotine. The drug is slowly destroyed in the liver and excreted in the
urine and faeces. This long delay makes it difficult
for law enforcement authorities to decide whether the
drug was in use while driving, if this should be an offence.
11.12.1 Tranquillizers 1,
major
tranquillizers, phenothiazines,
chlorchromazine (Largactil) promethazine (Phenergan) depressants
Product: Sleeping pills, minor tranquillizers
Street name: Benzos, ternazzies, Valium, tranks, sleepers, Serapax,
serries, Mandrax, mandies.
Symptoms: Drowsiness, confusion, incoordination, slurred speech,
depressed pulse rates, shallow breathing.
Potential problems: Anxiety, depression, restlessness, tremors,
insomnia, changes in eyesight, high risks of addiction, suicide.
Tranquillizers
These are drugs that sedate without inducing sleep. The major
tranquillizers are used in the treatment of schizophrenia by blocking
dopamine receptors in the brain. Many are based on
phenothiazine and its derivatives.
1. Aliphatic series
Generic name, Trade name
Chlorpromazine, Trade name: Largactil, Protran, Promacid
Promethazine, Trade name: Phenergan, "Meth-Zin", Progan, Prothazine,
Avomine
2. Piperidine series
Thioridazine Trade name: Melleril, Aldazine
Pericyazine, Trade name: Neulactil
3. Piperazine series
Generic name, Trade name
Prochlorperazine, Trade name: Stemetil, Compazine, Anti-Naus
Thiopropazate, Trade name: Dartalan
Fluphenazine, Trade name: Anatensol
Fluphenazine decanoate, Trade name: Modecate
Trifluoperazine, Trade name: Stelazine, Calmazine
4. Thioxanthine tranquillizers
are derivatives of phenothiazine that retain the sulfur atom but not
the
nitrogen.
Generic name, Trade name
Chlorprothizene, Trade name: Taractan
Clopenthixol, Trade name: Sordinol
Flupenthixol, Trade name:
Fluanxol
Thiothixene, Trade name: Navane
If the sulfur and the nitrogen atoms of phenothiazine are replaced
by
(-CH=CH-) and (-CH-) respectively, one of the derivatives is
protriptyline. All these compounds are used to relieve the
symptoms of schizophrenia
and reduce the likelihood of relapse. They affect the brain
stem
rather than the cortex. Their use has profoundly modified the
problems
of the mental hospital, but they do carry a high incidence of
adverse
reactions.
11.12.2
Tranquillizers 2, minor
tranquillizers, benzodiapines, diazepam
(Valium) oxazepam (Seraz, Serenid) nitrazepam (Mogadon)
flunitrazepam
(Rohypnol)
The most common of the minor tranquillizers are built up on a
benzodiazepine nucleus.
Generic name, Trade name
Oxazepam, Trade name: Serenid
Diazepam, Trade name: Valium
Nitrazepam, Trade name: Mogadon
Chlordiazepoxide, Trade name: Librium (sleeping pill)
Librium was used in the treatment of neuroses, behaviour disturbances,
alcoholism and as premedication for anaesthesia. Valium is used to
reduce symptoms of anxiety. The differences relate to how fast they
metabolize to the fast acting actual drug, nordazepam. Valium loses the
1-methyl group, while Librium hydrolyses the 2-methylamino group to an
oxygen.
The so-called "date rape" dugs are mainly Rohypnol (flunitrazepam) GHB
(gamma hydroxybutyric acid) and Ketamine (ketamine hydrochloride)
11.12.2.1 GHB
Product: Gamma-hydroxybutyrate (GHB)
Street name: Fantasy, grievous bodily harm (GBH) liquid ecstasy,
liquid E, G.
Symptoms: Drowsiness, induced sleep, nausea, reduced inhibitions,
dizziness, headache, increased sociability, initial euphoria leading to
confusion and agitation.
Potential problems: Extreme drowsiness, loss of consciousness,
hallucinations, difficulty focussing eyes, vomiting, impaired movement
and speech, reduced muscle tone, disorientation, convulsions/seizures,
coma, respiratory distress, slowed heart rate, lowered blood pressure,
amnesia, death. GHB can be addictive with prolonged use.
11.12.2.2 Ketamine
Product: Ketamine hydrochloride.
Street name: Green, K, super K, special K, Vitamin K.
Symptoms: Altered perception, disorientation, drowsiness,
hallucinations, numbness, strange muscle movements, nausea, vomiting.
Potential problems: Accidents from lack of coordination, quick
development of tolerance, weight loss and loss of appetite,
psychological dependence, psychosis, flashbacks, loss of memory,
attention and vision impairment. Ketamine is an anaesthetic. When used
with depressant drugs such as alcohol, heroin or tranquillizers, it can
be particularly harmful as it has the potential to shut down the body,
causing vital organs such as the lungs or heart to stop functioning.
11.12.3
Tranquillizers 3, minor
tranquillizers, dibenzazepine,
imipramine (Tofranil) desipramine (Pertofran) amitriptyline
(Tryptanol) nortriptyline (Allegron)
Tricyclic antidepressants
Depression is a problem that faces many people and the "tricyclics",
usually derived from dibenzazepine, form a popular family of
antidepressants. These drugs have as many side effects as the
tranquillizers. They present a particular problem of overdose abuse
Generic name, Trade name
Imipramine, Trade name: Tofranil, Imiprin, Melipramin, Desipramine,
Pertofran
Amitriptyline, Trade name: Tryptanol, Laroxyl, Saroten, Amitrip, Endep
Nortriptyline, Nortriptyline Trade name: Allegron, Nortab
Trimipramine, Trade name: Surmontil A, Doxepin, Sinequan, Quitaxon,
Deptran
An interesting series of drugs that are still occasionally used to
treat depression are the so-called monoarnine oxidase inhibitors (or
MAO inhibitors). The name means that they have the capacity to
inhibit an enzyme that is normally responsible for removing certain
substances such as norepinephrine
(noradrenaline) and serotonin from the body. Currently there is
considerable evidence that depressive illnesses are associated with a
decrease in the level of these amines in certain parts of the
central nervous system, so that by inhibiting their destruction,
their level is increased. An example of a biogenic is the amine
pheneizine that is similar to amphetamine.
MAO inhibitors
Generic name, Trade name
Iproniazid, Trade name: Marsilid (5% rate of liver damage)
Phenelzine, Trade name: Nardil, Nialamide, Niamid (less effective than
a
placebo)
(deleted from PBS) Isocarboxazid, Marplan, Tranylcypromine, Parnate
(strong "cheese" effect,)
Mebanazine, Trade name: Actomol (deleted from PBS)
Patients treated with these drugs have to be warned to avoid eating
cheese, red wine, certain beers, piquant foodstuffs such as Marmite and
Bovril, and must not take any other medication without consulting their
doctor. The reason for this is that these foodstuffs contain tyramine,
which is normally broken down in the alimentary canal. When
MAO-inhibiting drugs are used, the enzymes that do the breakdown
are inhibited, allowing tyramine into the bloodstream. This causes a
massive release of norepinephrine, which in turn causes a sudden
fluctuation in blood pressure, which produces intense headache and
sometimes death.
11.12.4 Drug
interactions
Drugs that are taken orally have to be absorbed through the gut, and
this can be influenced by other material present. By using
suitable
coatings a drug can be absorbed either in the acidic stomach or the
alkaline duodenum. Once the drug is in the plasma it can become bound
to protein and only a small percentage remains free and active. This
percentage can be drastically altered by another drug, which kicks the
first one off its protein site. Often use is made of this method to
boost the efficiency of a drug. Also, a drug can affect the efficiency
of an enzyme and hence influence the rate at which a second drug is
broken down by that enzyme. The MAO inhibitor drugs and the
consequences of eating cheese while they are being taken is a good
example.
The way and speed with which drugs are metabolized by the body can also
depend on genetic factors, so that comparisons between animals and
humans, and between individuals, can be misleading. They also depend on
physiological factors, such as age, diet, hormones (including the
effects of pregnancy) and disease states, especially if the liver is
involved. The old are particularly liable to be treated with several
drugs simultaneously and they, in particular, will have impaired
metabolism, which will affect the drug's effects on them.
Very often a drug is changed in the body to another compound. Sometimes
the new compound is inactive or it may be less active or more active
than the original. The original may even be completely
inactive and it is the new compound (metabolite) that is the "real"
drug. The body can be used as a chemical factory.
The
liver has an important role in the metabolism of drugs. Also, many
drugs used in treatment of illness have high molecular mass,
greater than 400, and as a consequence, are excreted in the bile
as
well as the urine, so they are frequently subject to bacterial
metabolism in the intestines. These products can be reabsorbed
and
further metabolized by the liver, producing a cycle of absorption,
metabolism by
the body, excretion, bacterial metabolism, reabsorption and metabolism
by the body.
11.12.5 Drug
tolerance
Drug users often develop tolerance to the chemical they
are using. In the case of the opiates most of the tolerance comes
from
the adaptation of the cells in the nervous system to the action of the
drug. In the case of alcohol, barbiturates and related
hypnotics, a
group of depressants of the central nervous system (CNS) chronic
use causes the capacity of the enzymes that metabolize the drugs
to
increase, i.e. you can remove the alcohol faster. Occasional
alcohol drinkers can
metabolize ethanol only with the liver's slow acting enzyme,
alcohol
dehydrogenase. Chronic drinkers are no more efficient with this
enzyme, but they induce a new alcohol destroying enzyme of the
P-450, cytochrome mono-oxygenase type in the liver. Such persons
can
do well on difficult tasks at blood alcohol levels above 0.2
mg / mL. After several weeks
of abstinence from drinking alcohol the capacity of this enzyme
declines, so that the
abstinent alcoholic and normal individual metabolize alcohol at the
same low rate. Chronic use often means a higher blood
concentration is
needed to produce the same effects, i.e. it produces
pharmodynamic
tolerance. This in turn means that to obtain the same effects, the
person will consume more of the drug. However, the fatal dose of the
drug does not change. The result is often death by overdose. When the
same enzymes are involved, tolerance to one drug can cause cross
tolerance to another, e.g. cross tolerance of alcohol with
benzodiazepine. So chronic drinkers will deal not only with
alcohol more effectively, but also with Valium. If they consume
both
drugs at the same time, the alcohol will monopolize the enzyme which
then is not free to deal with the Valium so the effect of the
Valium
is enhanced and prolonged. The point at which marked intoxication
is
caused by drinking alcohol can be monitored by measuring the blood
alcohol level or breath level. However, there is a difference
between the level which is found to correspond to intoxication "on the
way up", i.e. while drinking, compared to "on the way down", i.e.
after drinking alcohol has stopped because the effect on
behaviour
appears to be far less "on the way down" than "on the way up". So
motor car drivers caught by a breathalyser test the
morning after a heavy drinking may be unaware that their level is
still high. Westerners oxidize ethanol only
slowly in the first stage to acetaldehyde but Japanese and Chinese may
have a gene for an enzyme that
oxidizes it faster so a few sips of ethanolic beverage
bring a deep red colour to their cheeks and an unpleasant tingling.