Option D: Medicines and drugs (15/22 hours)The aim of this option is to give students an understanding of how medicines and drugs can influence the functioning of the body. Students should be able to recognize the fundamental structures and relevant functional groups of several classes of drugs and medicines (as listed in this option or in topic 10), and should be able to distinguish between them. Memorizing of complex formulas is not required. Throughout the option, the contribution that science has made (and continues to make) towards maintaining and improving the health and well-being of the world’s population should be stressed. Aim 8 discussions are central to this option. Core material: D1–D7 are core material for SL and HL (15 hours). Extension material: D8–D10 are extension material for HL only (7 hours). Pharmaceutical products Assessment statement Teacher’s notes
General y, a medicine or drug is any chemical that
drugs on the functioning of the body.
does one or more of the fol owing. • Alters the physiological state, including
consciousness, activity level or coordination
• Alters incoming sensory sensations• Alters mood or emotionsThe importance of the body’s natural healing processes and the placebo effect should be stressed.
Thalidomide case. The use of combinatorial
chemistry will not be assessed. A discussion of specific techniques will not be assessed. TOK: Should scientists be held moral y responsible when drugs have adverse effects?
Methods should include oral, parenteral (by
injection), inhalation and rectal. Injections may be intravenous, intramuscular or subcutaneous.
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Antacids Assessment statement Teacher’s notes
hydrogencarbonate. Students should be able to write equations for neutralization reactions and know that antacids are often combined with alginates (which produce a neutralizing layer, preventing acid in the stomach from rising into the esophagus and causing heartburn), and with anti-foaming agents (such as dimethicone). Analgesics Assessment statement Teacher’s notes
Mild analgesics function by intercepting the
pain stimulus at the source, often by interfering with the production of substances (for example, prostaglandins) that cause pain, swel ing or fever. Strong analgesics work by temporarily bonding to receptor sites in the brain, preventing the transmission of pain impulses without depressing the central nervous system. TOK: A discussion of pain perception could be linked to the more general discussion of perception as a way of knowing in TOK.
Aspirin has been found to be useful in preventing
the recurrence of heart attacks and strokes. The
disadvantages of aspirin include ulceration and
stomach bleeding, al ergic reactions and Reye’s
syndrome in children (a potential y fatal liver and brain disorder). Paracetamol is very safe in the correct dose but can, in rare cases, cause blood disorders and kidney damage. Overdosage can lead to serious liver damage, brain damage and even death.
Stress the functional group modification to the
structure of morphine that results in the semi-
synthetic drug diamorphine (heroin).
Include the social as well as physiological effects of
its derivatives as strong analgesics.
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Depressants Assessment statement Teacher’s notes
Describe the effects of depressants.
At low doses a depressant may exert little or no effect. At moderate doses the compound may induce sedation (soothing, reduction of anxiety). At higher doses it may induce sleep. At extremely high doses it may cause death. Depressants are often described as antidepressants because they relieve depression.
Include effects on the family, cost to society and
the short- and long-term health effects.
breathalyser, analysis of blood and urine by
chromatography, and absorption of infrared radiation or use of a fuel cell in the intoximeter.
Examples should include increased risk of stomach
bleeding with aspirin and increased risk of heavy sedation with any drug that has a sedative effect on the central nervous system.
Only the uses of diazepam (Valium®), nitrazepam
(Mogadon®) and fluoxetine hydrochloride (Prozac®)
Stimulants 2.5 hours Assessment statement Teacher’s notes
Amphetamines and epinephrine (adrenaline) are
chemical y similar in that both derive from the phenylethylamine structure. Amphetamines mimic the effects of epinephrine (adrenaline) and are known as sympathomimetic drugs.
Short-term effects include increased heart rate and
blood pressure and reduction in urine output, as well as stimulating effects. Long-term effects include increased risk of heart disease, coronary thrombosis and peptic ulcers. Include also the addictive properties of nicotine and the further risks associated with smoking tobacco.
Caffeine is a respiratory stimulant. When consumed
in large amounts it can cause anxiety, irritability and
sleeplessness. It is a weak diuretic. Both caffeine and nicotine contain a tertiary amine group.
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Antibacterials Assessment statement Teacher’s notes
Include the discovery by Fleming and the
development by Florey and Chain. TOK: What part does serendipity play in scientific discoveries?
Penicil ins work by interfering with the chemicals
that bacteria need to form normal cell wal s.
Modifying the side-chain results in penicil ins that are more resistant to the penicil inase enzyme. Aim 8: Strict adherence to a recommended
treatment regime is necessary for the effectiveness
of anti-TB drugs (frequently several drugs are used in combination). The use of penicil ins in animal feedstock also contributes to the resistance problem. Antivirals 1.5 hours Assessment statement Teacher’s notes
State how viruses differ from bacteria.
Antiviral drugs may work by altering the cel ’s
genetic material so that the virus cannot use it to multiply. Alternatively, they may prevent the viruses from multiplying by blocking enzyme activity within the host cel .
Discuss the difficulties associated with
Int: Specific proteins on the HIV virus bind to
a receptor protein on certain white blood cel s (T cel s). Because of the ability of the HIV viruses to mutate, and because their metabolism is linked closely with that of the cel , effective treatment with antiviral drugs is very difficult, as is vaccine development. The control and treatment of HIV is exacerbated by the high price of anti-retroviral agents and sociocultural issues. D8 Drug action 2.5 hours Assessment statement Teacher’s notes
Students should be aware that cis- and trans-
geometrical isomerism in drug action.
isomerism can occur in inorganic complexes and that the two different isomers can have different pharmacological effects. Examples should include the anti-cancer drug cisplatin.
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Assessment statement Teacher’s notes
The two enantiomers in a racemic mixture of a
drug may have very different effects, for example, Thalidomide. One enantiomer of Thalidomide al eviates morning sickness in pregnant women, while the other enantiomer causes deformities in the limbs of the fetus.
The high reactivity of the amide group within the
four-membered ring structure is a result of strain. The ring opens so that the penicil in becomes covalently bonded to the enzyme that synthesizes bacterial cell wal s, thus blocking its action.
The polar hydroxyl groups in morphine are replaced
by non-polar ester groups, facilitating transport into
the non-polar environment of the central nervous system. D9 Drug design 2.5 hours Assessment statement Teacher’s notes
Traditional y, a large col ection of related
compounds are synthesized individual y and evaluated for biological properties. This approach is time-consuming and expensive.
Combinatorial chemistry is used to synthesize
a large number of different compounds and
screen them for biological activity, resulting in a “combinatorial library”. Alternatively, paral el synthesis can produce smal er, more focused libraries. Students should be aware of the importance of solid-phase chemistry.
Three-dimensional models of drugs can be created
in silico and molecular model ing software can be used for the virtual development and evaluation of new drugs.
Students should be aware of the ability of acidic
(carboxylic acid) and basic (amine) groups to
form ionic salts, for example, soluble aspirin and
fluoxetine hydrochloride (Prozac®).
Describe the use of chiral auxiliaries to
A chiral auxiliary is used to convert a non-chiral
molecule into just the desired enantiomer, thus avoiding the need to separate enantiomers from a racemic mixture. It works by attaching itself to the non-chiral molecule to create the stereochemical conditions necessary to force the reaction to fol ow a certain path. Once the new molecule has been formed, the auxiliary can be taken off (recycled) to leave the desired enantiomer. An example is the synthesis of Taxol, an anti-cancer drug.
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D10 Mind-altering drugs Assessment statement Teacher’s notes
acid diethylamide (LSD), mescaline, psilocybin and tetrahydrocannabinol (THC).
Students should be aware of the similarities of all
three drugs and compare them to the indole ring. Aim 8: Arguments for legalization include the
ability of cannabis to offer relief from certain diseases. Arguments against legalization include the possible harmful effects and the possibility of cannabis users moving on to harder drugs.
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We define sports therapy as the enjoyment of any sport whichresults in improvements in gross motor function for individ-uals having neurological disorders or developmental disabil-ities. The introduction of sports therapy in the early formativeyears may have a significant impact on accelerating the reha-bilitation of children with neurological disorders or develop-mental disabilities, such as ce
Antibacterials
Assessment statement 
D10 Mind-altering drugs