D1: Pharmaceutical drugs
D.1.1 List the effects of medicines and drugs on the functioning of the
body.
Drug or
medicine is a substance that does one or more of the following:
·
Alters physiological state – consciousness, activity
level, coordination
·
Alters incoming sensory experience
·
Alters mood or emotion
The active
ingredients in drugs and medicines can be isolated from a plants and animals or
synthesized artificially.
Drugs
supposed to assist human body’s natural self-healing capabilities.
Placebos are drugs containing no active
ingredient, which “fool” the human body into healing.
D.1.2 Outline the stages involved in the research, development and
testing of new pharmaceutical products.
The research
and development of new medicines is a long and costly process. It usually takes
up to 12 years and costs more than $200 million.
1.
First the drug must be isolated or synthetized.
2.
The drug is tested on animals. LD50 and ED50
are determined.
3.
The drug moves to Clinical Trials
a.
Human Pharmacology – testing on small group of healthy volunteers for safety
b.
Therapeutic Exploratory – evaluates drug’s efficiency
and side effects
c.
Confirmatory Stage – large-scale testing of drug
4.
A local drug regulatory agency approves a medicine and
decides whether it will be
5.
OTC (over the counter) or on prescription only.
LD50 is a lethal dose necessary to kill 50 percent of animal population. ED50 is an effective dose, one creating a noticeable effect in 50% of animal population.
The ratio between LD50 and
ED50 is called the Therapeutic Index.
Therapeutic
Index = LD50 / ED50
Therapeutic
determines a safety of drug. If the therapeutic index of a drug is 10, a person
would have to intake ten times more drug than the effective dose for the
effects to be lethal. According to the therapeutic index, the researchers
decide whether a dosage must be controlled. If TI is low, the dosage must be closely controlled.
During
testing, half of the patients receive a real drug and the other half
similar-looking placebo. This determined whether the drug has a real effect or
the pill only fooled body into healing.
NOTE: We must know Thalidomide as an example of what can go
wrong during R&D process of a drug. Thalidomide alleviates morning sickness
during pregnancy. The drug’s development revealed severe side effects – babies,
whose mothers used the medicine, got born with deformed limbs.
D.1.3 Describe the different methods of administering drugs.
There are five ways of administering a drug:
1.
Injection
a.
Intravenous – veins
b.
Intramuscular – muscles
c.
Subcutaneous – under skin
2.
Orally – mouth
3.
Rectally – anus
4.
By inhalation
5.
Topically – on the skin (ointments, creams, …)
D.1.4 Discuss the terms therapeutic window,
tolerance and side-effects.
Therapeutic window – the difference between the effective
dose and lethal dose; also called therapeutic index
Side effects – the undesired effects of
drugs
Ex:
aspirin thins the blood (used as an
anti-clotting agent to prevent a hearth attack)
Morphium, the pain reliever, causes
constipation.
Tolerance – a person taking a drug often
gets used to the active ingredient, so it takes larger and larger doses to
obtain the drug’s desired effect. There is a danger that a body would create a
physical addiction to a drug. For instance, an addiction to
caffeine: if the addict does not get his/her coffee, he/she gets headaches. Another issue is
that with increasing dose, the user is coming closer and closer to the lethal
dose.
Risk-to-benefit ratio – determines
whether the side effects (risk) of the drug are acceptable in relation to its
curing effects; for example, a drug curing baneful disease would be accepted
despite high risks
D2: Antacids
D.2.1 State and explain how excess acidity in the stomach can be
reduced by the use of different bases.
Human
stomach contains gastric juices secreted by some cells of the stomach walls.
The gastric juices are acidic, with pH between 1.0 and 3.0, because they
contain hydrochloric acid (HCl). Excessive acid production causes heartburn and damage of the mucus
covering the walls of the stomach. Moreover, excess production of acid creates
an ideal environment for the bacteria Helicobacter pylori, causing peptic
ulcers.
Hearthburn – the situation when gastric
juices overflow through esophagus
Ulcers – scars on the walls of stomach,
indirectly caused by an excessive acidity.
Antacids are weak bases, utilized to
neutralize the excess acidity in a human stomach. They relieve the pain of
ulcers and prevent ulcers and heartburn from happening. Antacids are metal
oxides, hydroxides, carbonates or hydrogencarbonates.
Antacid
|
Ingredient Name
|
Chemical Formula
|
Tums
|
Calcium
carbonate
|
CaCO3
|
Gaviscon
|
Aluminum
hydroxide
|
Al(OH)3
|
Milk of
Magnesia
|
Magnesium
hydroxide/oxide
|
Mg(OH)2,
MgO
|
Common ingredients of antacids are
alginates and anti-foaming agents.
Alginates create a layer of mucus on the
walls of stomach and in esophagus, which prevents the heartburn.
D3 Anelgesics
D.3.1 Describe and explain the
different ways that analgesics prevent pain.
Analgesics are drugs that
relieve pain. They can be mild or strong.
Mild analgesics intercept the
pain stimulus at its source. Modes of operation: (1) interfere with the
production if prostaglandins, chemicals that cause pain; (2) reduce fever; (3)
reduce swelling.
Strong analgesics (narcotics)
relieve pain by temporarily bonding to the pain receptors in in the brain. They
prevent the transmission of pain impulses into the brain.
D.3.2 Describe the use of
derivatives of salicylic acid as mild analgesics and compare the advantages and
disadvantages of using aspirin and paracetamol (acetaminophen).
Salicylic acid was an analgesic obtained from the bark of willow trees.
However, salicylic acid had severe side effects. Therefore, researchers
modified the structure of salicylic acid, creating derivatives. Derivative
molecules mean they have different active groups attached to them.
Derivatives of salicylic are used as mild analgesics. They control the
release of prostaglandins and thus reduce pain. Two examples of derivatives of
salicylic acid are aspirin and paracetamol. Both medicines are
painkillers and reduce fever (antipyretic). However, only aspirin reduces inflammation.
Aspirin
|
Paracetamol
|
||
Advantages
|
Disadvantages
|
Advantages
|
Disadvantages
|
·
Prevents blood clotting, so prevents heart
attacks
·
Reduces inflammation
|
·
Irritates stomach walls, so may induce peptic
ulcers and stomach bleeding
·
Allergic reactions
·
Reye’s syndrome in children, a potentially
fatal liver and brain disorder
|
·
Safe in the correct dose
·
Safe for children
|
·
Blood disorders
·
Kidney damage
·
Overdose – liver damage, brain damage and
death
|
D.3.3 Compare the structures of
morphine, codeine and diamorphine (heroin, a semi-synthetic opiate).
Morphine, codeine and diamorphine
(heroin) are powerful strong analgesics, which block the perception of pain
in the brain.
Morphine
|
Codeine
|
Diamorphine (heroin)
|
 |
 |
 |
Benzene ring
Ether
Alkene
Alcohol
(x2)
Tertiary amine
|
Benzene ring
Ether
(x2)
Alkene
Alcohol
Tertiary amine
|
Benzene ring
Ether
Alkene
Ethanoate
(x2)
Tertiary amine
|
Morphine and codeine are obtained from the opium (found in the puppy
plants). Low concentrations of heroin can be found in opium; however, this drug
is usually prepared synthetically.
Morphine + ethanoic acid → heroin + water
The reaction between morphine and ethanoic acid is a condensation
reaction. The acid reacts with alcohol groups in morphine (also referred to as
hydroxy or –OH groups). The product of the reaction is water and heroin.
D.3.4 Discuss the advantages and
disadvantages of using morphine and its derivatives as strong analgesics.
Morphine
|
Codeine
|
Diamorphine (heroin)
|
|||
Adv.
|
Dis.
|
Adv.
|
Dis.
|
Adv.
|
Dis.
|
· Management of severe pain
such as advanced cancer
· Treatment of diarrhea
|
· Major side effect –
constipation
· Can lead to dependence
|
· Second stage pain
treatment with paracetamol and aspirin
· Cough treatment
· Fewer side effects than
morphine and heroine
|
· May not completely treat
the pain
|
· Relief of very severe pain
· Euphoric effects
|
· Strong addiction with
rapidly increasing tolerance
· Dependence leads to
withdrawal symptoms
· Death
· Productivity cost due to
money spend on drugs
|
D4 Depressants
D.4.1 Describe the effect of
depressants.
Depressants are drugs that
depress (calm and relax) the central nervous system by interfering with the
transmission of nerve impulses in the neurons.
Effect by dose:
Low doses – increase feeling of calm, drowsiness, increased
spontaneity, slower mental activity
Moderate doses – soothing, reduction of anxiety, altered perception
High doses – slurred speech, faltering movement, altered perception,
sleep
Extremely high doses – low breathing and heart rates, sleep, coma,
death
Effect by type:
Tranquilizers
(alcohol, valium) reduce nervous tension without inducing sleep in moderate
doses.
Sedatives (barbiturates) sooth distress without
inducing sleep in moderate doses.
Hypnotics (chloral hydrate) induce sleep.
NOTE: Depressants are often described as anti-depressants because they relieve depression.
D.4.2 Discuss the social and
physiological effects of the use and abuse of ethanol.
Short-term:
|
·
Loss of self-restraint
·
Impairment of memory and concentration
·
Loss of balance
·
‘hangover’ – dehydration and headache due to increased
urine output
·
Vomiting, loss of consciousness, coma and
death
·
Violent behavior at home – domestic abuse
·
Driving under influence – car accidents
|
Long-term:
|
·
Dependence - alcoholism
·
Liver disease – cirrhosis or cancer
·
Fetal alcohol syndrome
·
Coronary heart disease
·
Permanent brain damage
·
Deterioration of relationships, and a general
decrease in performance in daily activities
|
D.4.3 Describe and explain the
techniques used for the detection of ethanol in the breath, the blood and
urine.
Breath analyzer contains
acidified potassium dichromate(VI) crystals, which turn from orange to green as
they are reduced by ethanol in breath. Works because ethanol passes from
stomach to the blood and to the lungs, where blood-air equilibrium is established.
Fuel cell may also contain
acidified chromium(VI) crystals. In this device, the ethanol is oxidized using
an oxidizing agent, which generates electricity. The potential difference,
generated by the redox reaction, is proportional to the alcohol contained in
the blood.
Infrared absorption intoximeters
use infrared spectroscopy to determine the alcohol content. The C-H bond in
ethanol absorbs particular infra-red wavelength and the apparatus measures how
much at this wavelength is absorbed. Depending on how much light the sample
absorbs, the amount of ethanol in breath can be determined. May not work with
diabetics, who breathe out a lot of ketones, which shows a false positive.
Gas-Liquid Chromatography (blood
and urine) Can only be done in a laboratory. Gives very accurate results.
Blood or urine is vaporized and injected into a stream of an inert gas over the
surface of a non-volatile liquid. Due to their different solubilities and
boiling points the molecules in the blood or urine travel as different speeds
along the liquid. The time taken to move along the liquid is called the
retention time.
D.4.4 Describe the synergistic
effects of ethanol with other drugs.
Ethanol may increase the effect of a drug: alcohol increases the risk
of stomach bleeding with aspirin and boosts the potency of sedatives. Also,
ethanol increases toxic effects of paracetamol. Alternatively, ethanol may
reduce/negate effects of some drugs.
D.4.5 Identify other commonly
used depressants and describe their structure.
Other commonly used depressants include Valium, Mogadon and Prozac.
They can be all found in the data booklet. Valium and Mogadon have a similar
structure, but Valium contains Cl on its benzene ring, while Mogadon contains
NO2 on its benzene ring.
Uses:
Valium – treats anxiety and tension
Mogadon – sleeping pill, contains seizures and infant spasms
Prozac – improves mood by making serotonin more available
D5 Stimulants
D.5.1 List the physiological
effects of stimulants
Stimulants are drugs which increase a person’s state of mental
alertness. All stimulants tend to increase concentration, but other
psychological effects vary according to the given stimulant. Stimulants
decrease appetite.
Generally speaking, the physiological effects of stimulants are:
1)
Increased blood pressure and heart rate
2) Constriction
of arteries
3) Dilation
of pupils
4) Sweating
5)
Reduced appetite
D.5.2 Compare amphetamines and
epinephrine (adrenaline).
Amphetamines mimic the effects of adrenaline (epinephrine), the “flight
or fight” hormone. Amphetamine is a sympathomimetic drug: it mimics the
stimulation of the sympathetic system, a structure responsible for subconscious
reflexes, by adrenaline.
Structural similarities: Both adrenaline
and amphetamine have (1) a benzine ring and (2) an amine.
Strutural differences: In adrenaline the
amine is primary, while in amphetamine it is secondary. Also, adrenaline
contains three alcohol groups, while amphetamine does not.
Both amphetamine and adrenaline speed up
the heart rate and blood pressure. Thus, they work to avoid sleeping
(narcolepsy=uncontollable desire to sleep). In the short term, amphetaines increase mental
energy, reduce apetite and induce a sense of euphoria. In the long-term,
amphetamines can lead to severe addicition and depression.
D.5.3
Discuss the short and long term effects of nicotine
consumption.
Nicotine is a sympathomimic drug,
contained in tobacco leaves.
Short-term effects:
1) Increased heart rate and blood pressure
2)
Reduction in
urine outpute
3)
Increased mental alertness
and physical energy
4) Constricts blood vessels which puts stress on the
heart
Long-term effects:
1) Risk of heart disease and coronary thrombosis due to
the strain it puts on the heart
2)
Risk of peptic
ulcers due to excess production of gastric juices
3)
Tolerance and
addiction
4) Cost to society and family – smokers spend large
amount of money on cigarettes
D.5.4
Describe the effects f caffeine and compare its structure with that of
nicotine.
Effects of caffeine include,
(a) In small amounts
1) Frequent unrination
2) Increased concentration and alertness
3) Increased breathing rate
(b)
In large amounts
1) Anxiety
2) Irritability
3) Sleeplessness (insomnia)
4) Addiction and withdrawal symptoms such as nausea
Caffeine
|
Nicotine
|
 |
 |
Pentagon
ring
Hexagon
ring
Tertiary
amine (1)
Alkene
Secondary amide (2)
|
Pentagon
ring
Hexagon
ring
Tertiary
amine (1)
Alkene
|
D.6 Antibacterials
D.6.1 Outline the historical
development of penicillin.
Discovery of penicillin is usually attributed to the Scot Alexander Fleming. Fleming left an open
dish with Staphylococcus aureus, in
his laboratory and when he returned from a holiday, a mold grew inside the
petri dish. This mold inhibited the growth of bacteria. Fleming publishes his
results in 1929, but he did not pursue the discovery.
Penicillin was pursued by Howard
Florey and Ernst Chain, who
isolated and purified penicillin. They also showed the penicillin was harmless
on mice and as the first used the drug on humans. The two men received a Nobel
Prize for Chemistry. In the US, companies started mass production of penicillin.
First, by growing the fungi in large tanks and then by synthetizing the drug.
D.6.2 Explain how penicillins
work and discuss the effect of modifying the side chain.
Penicillin is bactericidal, which means it kills bacteria.
1)
Penicillin interferes with the enzymes that bacteria
need to form normal cell walls.
2) Attempting
cell division, bacteria swell and osmotic pressure puts stress on their cell
wall
3)
The cell walls burst and bacteria disintegrate
All penicillins have common structure, including the beta-lactam ring.
The beta-lactam ring is a square arrangement of carbon and nitrogen atoms with
other atoms attached. The R- is a functional group attached to the penicillin.
Different functional groups provide penicillin different properties.
Some bacteria developed resistance against penicillin and produce the enzyme
penicillinase, which breaks break down the beta-lactam ring. Attaching
different functional groups can make penicillins more resistant to penicillinase.
Also, some penicillins, such as Penicillin G, had to be injected as they got
broken down by the stomach acid – nowadays, the functional groups were
modified, so that penicillin can be taken orally.
D.6.3 Discuss and explain the
importance of patient compliance and the effects of penicillin over
prescription.
1)
Due to the use of antibiotics to cure minor ailments,
some bacteria became resistant to certain kinds of penicillins.
2) Harmless
and helpful bacteria in the digestive system can be wiped out.
3)
Bacteria mutate, which results in “superbugs” resistant
to antibiotics. This requires costly development of new antibiotics.
Patient compliance is important to avoid mutation of bacteria, but also
to ensure no allergic reaction will occur (many people are allergic to
penicillin).
Farmers often add antibiotics into feedstock to prevent illnesses and
to bolster the growth of animals. This may result in a mutation of harmless
bacteria. Humans consume the meat, taking in the antibiotics as well as the
resistant bacteria in.
D.7 Antivirals
D.7.1 State how viruses differ from bacteria.
Relevant points:
1) viruses are 20x smaller than
bacteria;
2) unlike bacteria viruses are
not cellular – bacteria have cell wall and nucleus
3) viruses do not have
cytoplasm, while bacteria do
4) viruses do not feed, excrete
and grow, while bacteria does
5) viruses use cell material of
the invaded cell to reproduce themselves, while bacteria use cell division
Viruses inject their RNA or DNA into their host cell’s cytoplasm and
use the cell to replicate. The new cell either releases the virus or releases
other infected cell. This change in cell structure cause symptoms of viral
infection.
D.7.2 Describe the different
ways in which antiviral drugs work.
1) Prevent viruses from leaving the host cell.
2) Block the reverse transcriptase enzyme activity to avoid a
conversion of the virus into a form that can enter the host cell.
3) Alter the host cell’s genetic material, so that viruses cannot use
it to multiply.
4) Block the enzyme activity within the host cell, so viruses cannot
multiply.
D.7.3 Discuss the difficulties
associated with solving the AIDS problem
The antiviral agents are very expensive, which makes treatment of HIV
difficult in developing countries. People cannot afford the drugs.
There are sociocultural issues fostering the spread of HIV, too:
Sociocultural
issue
|
Why is this a valid issue?
|
Condom use
|
Cultural resistance and high cost
|
Cultural factors
|
Misinformation, ignorance and wishful
thinking
|
Illegal activities
|
Drug use and prostitution
|
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