D3 Analgesics

D.3.1 Describe and explain the different ways that analgesics prevent pain

Mild analgesics: intercepts the pain stimulus at the source, often by interfering with the production of prostaglandins that cause pain, swelling and fever.Strong analgesics: work directly on the brain. They temporarily bond to receptor sites in the brain preventing the transmission of pain impulses without depressing the CNS.

D4 Depressants

D.4.1 Effects of depressants At low doses, depressants may have little or no effect At moderate doses, compound may induce sedation – reduction of

anxiety, soothing effect At high doses, depressants may induce sleep Extremely high doses can result in death

D.4.2 Social and psychological effects of abuse of ethanol

Background:The actual mode of action of ethanol is not fully understood: at low concentrations it is a stimulant but at high concentrations it becomes a depressant.However most of the problems attributed to ethanol (C2H5OH) are probably due to the action of ethanal (CH3CHO) formed from ethanol by the enzyme alcohol dehydrogenase (ADH) in the liver.This compound interacts with neurotransmitters to produce chemicals with psychotropic activity.Ethanal is then metabolized to ethanoate ions (CH3COO−) and eventually to water and carbon dioxide. The average 70 kg human male can oxidize about 10 grams of ethanol per hour.

Effect on family life and cost to society: Alcohol is addictive, can cause hardship to the families of addicts as

financial situation can become strained – family income can be spent on large amounts of alcohol instead of food and other essential items.

Many people become bad tempered and violent under the influence of alcohol, butting the wellbeing of friends and family at risk.

Lack of productivity can result in unemployment. Alcohol slows mental performance and response times making activities

such as driving or operating of heavy machinery dangerous.

Long-term health effects of ethanol: Cirrhosis of the liver Cancer (of liver and other organs) Increased risk of coronary heart disease and high blood pressure

Increased risk of stroke Anxiety and depression Poor eating habits Changes in physical appearance Alcoholic hepatitis and fatty liver

Short-term health effects of ethanol: Anaesthetic effect on the brain – slows thoughts and actions. Reaction

time and coordination is impaired. Heart rate speeds up. Blurry vision and slurred speech. Diuretic effect can cause dehydration. Can cause stomach upsets, heartburn, sickness and diarrhoea.

D.4.3 Techniques used for detection of alcohol in breath, blood and urine

D.4.4. Synergistic effect of ethanol with other drugs

Synergistic effect: when the combined action of two or more drugs is greater than the sum of their separate, individual effects

Increased risk of stomach bleeding when ethanol consumed in combination with aspirin

Increased risk of heavy sedation when ethanol consumed in combination with any drug that has a sedative effect on the CNS.

D.4.5 Identify other commonly used depressants and describe their structures.

The basic structure of benzodiazepines and nitrazepams is the seven membered ring fused to an aromatic ring with four main substituent groups.

However, fluoxetine hydrochloride is structured differently from the benzodiazepines. It has two aromatic rings bonded to an ether group. On the opposite end of the molecule, there is a secondary amine present as NH2

+ forming a salt with the Cl- ion.

D5 Stimulants

D.5.1 List the physiological effects of stimulants Increase in heart rate and blood pressure Increase in breathing rate Dilation of pupils in the eyes Constrictions of arteries Sweating Reduction in appetite

D.5.2 Compare amphetamines and epinephrine (adrenaline)

Amphetamines and adrenaline (the hormone) stimulate the central nervous system in similar ways. Adrenaline induces the ‘fight or flight’ response – increasing supply of oxygen and glucose to the brain and muscles. Immune system and other non-emergency bodily procedures are supressed.

The ability of amphetamines to mimic adrenaline causes it to be known as sympathomimetic drugs. They are addictive; their main effects are to:

Increase loco motor stimulation Induce a sense of euphoria and excitement Temporarily reduce appetite Increases heart rate, blood flow and rate of respiration Increases wakefulness – causing restlessness and insomnia

Both amphetamines and adrenaline are similar in their phenyl ethylamine structure.

D.5.3 Discuss the effect of short term and long term effects of nicotine consumption

Short term effects of nicotine Long term effects of nicotine Increases alertness Reduction of anxiety and tension Constricts blood vessels putting

strain on the heart Increased heart rate Increased blood pressure Reduction in urine output Stimulating effects

Increased risk of heart disease, including angina

Coronary thrombosis Peptic ulcers Physical and psychological

dependence – note that nicotine is addictive and can lead to withdrawal symptoms

Thee are further risks associated with smoking tobacco, not only from the effects of nicotine.

Other substances in cigarette smoke increase risk of mouth, throat and lung cancer

CO in cigarette smoke reduces the ability of the blood to carry O2

Increased risk of bronchitis and emphysema Cigarettes are costly, so a nicotine addiction increases financial strain

on families.

D.5.4 Describe the effects of caffeine and compare its structure with that of nicotine.

Caffeine stimulates the central nervous system by increasing the metabolic rate of nerve cells.

Moderate doses Higher doses Enhances alertness, wellbeing,

energy, motivation and concentration.

Mild diuretic

Affects physical coordination of the user.

Can cause sleeplessness, anxiety and irritability.

Caffeine is not physically addictive but can lead to mild psychological addiction. Caffeine constricts cerebral blood vessels. Quitting the ‘habit’ may produce powerful headache as the constricted blood vessels dialate.

Both caffeine and nicotine contain 3o amine groups.Both caffeine and nicotine also contain 6 and 5 membered rings – in the case of caffeine, these rings are fused and the 6 membered ring also contains 2 carbonyl groups.

D6 Antibacterials

D.6.1 Outline the historical development of penicillin

D.6.2 Explain how penicillins work and discuss the side effects of modifying the side chain.D.6.3 Describe and explain the importance of patient compliance and the effect of penicillin over prescription

D7 Antivirals

D.7.1 State how viruses differ from bacteria

Bacteria VirusLiving Non-livingSingle celled micro-organism Non-cellular and sub-microscopicBacteria contain: Single chromosome in the

nucleoid Rigid cell wall A cell membrane Cytoplasm Ribosomes

Viruses contain: A central core of DNA or RNA

with a protein coat No nucleus, cytoplasm,

ribosomes, cell membrane or cell wall

The enzymes invade a cell and replicate their nucleic acids

Feed Excrete Grow Reproduce asexually

Do not feed, excrete or grow Use the ribosomes of the cell

they have invaded to reproduce

D.7.2 Describe the different ways in which antiviral drugs workD.7.3 Discuss the difficulties associated with solving the AIDS problem