Topic: Effects of medicines on human

Target group

High school / technical school student

Core curriculum

New core curriculum:

High school and technical high school. Chemistry – basic level:

XXI. Chemistry around us. Pupil:

4) explains what they can rely on and what the healing and toxic properties of the substance depend on chemical (dose, water solubility, fragmentation, way of penetration into the body), e.g. aspirin, nicotine, ethanol (ethyl alcohol);
5) searches for information on the effects of components of popular drugs (e.g. coal activated, aspirin, agents that neutralize excess stomach acid).

High school and technical high school. Chemistry – extended level:

XXI. Chemistry around us. Pupil:

4) explains what they can rely on and what the healing and toxic properties of the substance depend on chemical (dose, water solubility, way of penetration into the body), e.g. aspirin, nicotine, ethanol (ethyl alcohol);
5) searches for information on the effects of components of popular drugs (e.g. coal activated, aspirin, agents that neutralize excess stomach acid).

Old core curriculum:

High school and technical high school. Chemistry – basic level:

XXI. Chemistry around us. Pupil:

3) explains what can be relied on and what determines the healing and toxic properties of chemical substances (dose, water solubility, fineness, way of penetration into the body) e.g. aspirin, nicotine, ethanol (ethyl alcohol);
4) searches for information on the effects of the ingredients of popular medicines (e.g. activated carbon, aspirin, agents that neutralize excess acid in the stomach).

General aim of education

The student discusses the effects of selected drugs on humans.

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basic competences in science and technology;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• explain the necessity of strict adherence to the rules of using medicines as prescribed by a doctor;

• explain the consequences of non‑compliance with the doctor's advice when taking medication;

• explain that excessive use of various substances harms human health;

• exchange and discuss factors influencing the healing and toxic properties of chemical substances.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • film;

  • exposition.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers;

• sheets of gray paper;

• colored markers.

Lesson plan overview

Introduction

1. The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).

2. The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.

3. Health and safety – before starting the experiments, students familiarise themselves with the safety data sheets of the substances that will be used during the lesson. The teacher points out the need to be careful when working with them.

Realization

1. The teacher introduces students to the issue of using medicines for therapeutic purposes. Indicates that the mechanisms of functioning of organisms are very complicated, and their course is influenced by many chemical compounds. Some of them improve their work, others disrupt it or even cause death. Medicinal substances modify the body's activities to prevent or eliminate the disease. They also destroy microorganisms that cause health problems - here the teacher and the students determine the concept of drug substance and drug.

2. Students read the fragment „Healing and toxic effects of chemical substances” and discuss the concept of therapeutic dose and toxic dose. The teacher discusses the toxicity classes and factors determining the effect of medicinal substances.

3. The teacher divides the class into three groups. Handles sheets of gray paper and markers. Students using the abstract, textbook and the Internet, develop the indicated content: group I - analgesics, group II - drugs for hyperacidity, group III - antibiotics. They should take into account the use and action of medicines, as well as ways to eliminate the causes of diseases, and not just their effects. After completing the work, the group leaders discuss the effects of the activities. The teacher sums up the students' work.

4. The lecturer announces the experiment „Testing the properties of acetylsalicylic acid” in accordance with the instructions in the abstract. Instructs the students to write down the research question and the hypothesis in the abstract form. Then, he conducts the experiment and the students write down their observations and conclusions. The teacher indicates the person who shares his insights and explains the reasonableness of the conclusions he has made.

5. The teacher conducts the experiment „Study of the action of hyperacidity drugs” according to the instructions in the abstract. Before joining the action, he asks the students to formulate a research question and a hypothesis and write them in the form in an abstract. After the experiment, a summary of observations and conclusions is made, which should also be included in the form.

6. Students perform an interactive exercise. The teacher makes sure that the task has been correctly completed and gives feedback.

Summary

1. The teacher plays the recording of the abstract. Every now and then he stops it, asking the students to tell in their own words what they have just heard. In this way, students consolidate information learned during the lesson and practice listening comprehension.

2. The teacher asks the students questions:

   • What did you find important and interesting in class?

   • What was easy and what was difficult?

   • How can you use the knowledge and skills you have gained today?

   Willing/selected students summarize the lesson.

Homework

1. Prepare 5 questions about the area that could be found on the test of the lesson.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Effects of medicines on human

Almost all chemicals can have a positive or negative (toxic) effect on the human body. The substance's action on the body is connected with its chemical structure and physicochemical properties as well as the amount administered into the body.

• Compounds easily soluble in water and easily dissociating are usually more active, because these are more quickly involved in metabolic processes in our body.

• The degree of substance fragmentation is also important, and this applies not only to dissolution processes, for example asbestos dust is harmful if its particles have a diameter less than 1 μm (1 µm = 10Indeks górny -6^-6 m) – inhaled causes pneumoconiosis, which leads to lung cancer.

• An important role is played by the shape of the molecule (mutual arrangement of the atoms that build it), because the course of many processes in organisms requires a very precise spatial matching of the reacting molecules of chemical compounds.

Not only are the properties important, but also the amount and concentration of the substance administered into the body – dose and the manner of its percolation into the body. For medicines, the therapeutic dose is determined, i.e. the smallest amount of substance that produces the desired therapeutic effect, without causing serious disturbances in the metabolism of the body.

In toxicology, the dose amounts are determined in relation to the harmful effects of the substance (poison) on the body.

Toxic properties of substances (poisons) are determined on the basis of lethal dose LDIndeks dolny 50₅₀ (Latin dosis letalis), i.e. the amount that causes the death of half of test subjects in the group, and the toxic dose TD (Latin dosis toxica), i.e. the amount of substance that causes pronounced toxification of the body .

Chemical substances can get into our body in various ways, for example through the respiratory tract (aerosols), through the digestive system (powders, liquids) and through the skin and mucous membranes (ointments).

Acetylsalicylic acid (ASA) – one of the first painkillers in the world. Since ancient times people made medicines from plants. In antiquity, cold or rheumatism were treated with extracts from willow bark or raspberry juice. Both of these peculiarities contain salicylates – derivatives of salicylic acid.

Currently, acetylsalicylic acid and its compounds hit the market in the pharmacies under the name aspirin. Aspirin is one of the most popular drugs used in the pharmacology of 20th century.

The analgesic effect of aspirin consists in inhibiting the production of prostaglandins in damaged cells that send information to the brain through nerve fibres. In contrast, anticoagulant action is based on the dilution of blood, which is why people who take high doses of aspirin may have, for example, nosebleeds. Although it is a one‑component, simple drug, scientists are still finding new applications.

It is a reaction typical for a group of compounds containing in their structure a characteristic element - a phenolic group. In the case of poorly stored or expired medicines containing aspirin, this test allows to determine qualitatively the presence of undesired salicylic acid.

Gastroenterologists (specialists in stomach and intestinal diseases) claim that about 5–7% of the population suffers from chronic stomach conditions, and at least 30–40% suffer from these symptoms once a month. People suffering from hyperacidity, associated with too aggressive action of hydrochloric acid on the stomach walls, use various types of neutralizing agents.

Neutralizing agents available in pharmacies contain salts or hydroxides of magnesium, calcium and aluminium. The basis of their action is the binding of hydrogen ions and increasing the pH in the stomach. This leads to partial neutralization of the acid gastric contents, as well as a partial reduction of pepsin (digestive enzyme) activity.

The process that takes place in the stomach after taking neutralizing agents can be presented as the equation of neutralization reaction of base with an acid:

${\mathrm{H}}_3{\mathrm{O}}^{\mathrm{+}}+{\mathrm{OH}}^{-}\to 2{\mathrm{H}}_{\mathrm{2}}\mathrm{O}$

Gastric juice is secreted by the glands and epithelial cells of the gastric mucosa. During the day, the stomach secretes 2500–3000 cmIndeks górny 3³ of gastric juice with a pH of 1.0 to 1.5. Under physiological conditions, hydrochloric acid has a constant concentration, only its volume in the gastric juice changes. The main role of hydrochloric acid is acidification of gastric juice and facilitating the digestion of proteins and the elimination of bacteria that get into the stomach with food. Heartburn arise as a result of throwing acidic stomach contents into the oesophagus.

Another drug commonly used in the case of stomach conditions is active carbon, also known as therapeutic or activated carbon. The healing effect of this substance is related to its sorption properties. After administration, it has a strong anti‑diarrheal effect. It is used in cases of food poisoning and poisoning with certain drugs and chemical compounds. It is characterized by a large absorbing surface and binds substances that cause poisoning, e.g.: paracetamol, ibuprofen, barbiturates, alkaloids, heavy metal salts. After administration, it is not absorbed from the gastrointestinal tract and is excreted.

To inhibit the growth of microorganisms, especially pathogenic bacteria, medicine uses antibiotics. These are organic compounds with a complex chemical structure, produced from metabolites of mould and fungi. In this way, so‑called natural antibiotics are produced. The medical industry is focused on the production of semi‑synthetic antibiotics:

• more effective – stronger with wider range of activity,

• chemically more durable,

• more resistant to bacterial enzymes,

• often cheaper to produce than natural medicines.

Biotechnological methods are used in the production of many antibiotics. The first natural antibiotic was penicillin. It was obtained from mould (a kind of fungi – Penicillium, which appears, for example, in rotten bread, fruits.

Currently, the pharmaceutical industry produces hundreds of antibiotics. Some attack many types of bacteria, others act only against one or two types of bacteria (these are selective).

Antibiotics, as all medicines, should always be taken in the right amount and as directed by your doctor. This is especially important because, apart from killing or neutralizing pathogenic bacteria, these also destroy the bacteria of gastrointestinal tract necessary for human. Very often it causes inflammation of the mouth and mycosis and leads to the multiplication of antibiotic‑resistant strains, which can be a serious health risk. Frequent bacterial resistance to the drug is associated with irrational antibiotic therapy.

• Chemical substances may affect the human body and cause the desired effect as expected (drugs) or act adversely - toxic (poisons).

• This is primarily determined by the dose of the substance and the way it penetrates the body (through the skin, respiratory system or digestive system). When using medication, it is very important to follow the doctor's instructions – take the right doses of the medicine and administer it during a sufficiently long period.