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Case-lesson “How does medicine work”
Case-lesson “How does medicine work”

Level (grade): 10+

Subject: Applied science

Objective: To gain knowledge about the working mechanism of drugs in terms of contemporary chemistry and biology, about innovation technology – already existing and prospective in this area.

Category: Science, nature and human
What information is waiting for me here?

  • What is a medicament?
  • What does happen with it inside human body and how does it work?
  • Is vaccination a medicine?
  • How do animals treat themselves?
  • What fundamental and practical knowledge will I need?
  • What meds are the most modern?
  • Where does the cost of vitamins come from?
6 scans of the subjects, phenomena and practices:

A lot of people are curious about how a pill “knows” to which sick organ to “go” and cure it, right? We take medication and vitamins to prevent diseases. We drink potions and pills when we get sick, and sometimes even get shots. But what does happen in the body when medicine gets into it? Why do drugs treat? Let’s find answers to these questions together.



Currently, about 30.000 various drugs exist to treat tens of thousands of illnesses. A separate group consists of vitamins and mineral supplements, which the body often lacks, but which are necessary for prevention of diseases and increasing the resisting capabilities of the body. We use drugs of natural or synthetic origin. And it often misleads people who believe that synthetic remedies are poorly digested by the body, which is not true. Many diseases are treated exactly by these drugs. We can also accentuate traditional and homeopathic medications that may not have an immediate effect. But the long-term (and harmless) usage of them gives a desired therapeutic effect. How to understand all this vast variety of drugs in terms of their biological significance?

Drugs of natural origin are derived from natural (vegetable, animal or mineral) raw materials. Some examples are honey, aloe, cod-liver oil, garlic. They can be received in natural form or after processing (extraction of an active component) and encapsulation.


Raw materials themselves are biological, akin to organic and inorganic matter of human body. They are incorporated into human body’s processes more easily than other substances.

Synthetic drugs are derived as result of chemical transformations or chemical synthesis. An example is aspirin. Aspirin is the first synthetic remedy ever. It is a widespread drug sold under a series of names and titles. It is based on acetylsalicylic acid. It is used as an antipyretic, analgesic and anti-inflammatory agent.


From this group we can distinguish a special subgroup – antibiotics. These are substances of synthetic or semisynthetic origin that inhibit the growth of living cells, usually prokaryotic or protozoa (pathogens). An example is penicillin. Penicillin antibiotics are historically significant because they are the first effective drugs against many serious diseases: infections caused by staphylococci and streptococci.


Another important point is that over time strains of microorganisms adapt to the effects of drugs – antibiotics. Therefore, there is a need to search for new remedies.

Another interesting aspect is “georeferencing”. It is the feature of strains, typical for a certain area. Therefore, the effectiveness of drugs will depend on their “georeferencing”: for what strain of what area especially they are intended.

One of the most tenacious misconceptions of our time is the treatment of viral diseases with antibiotics. Antibiotics have no effect on viruses, since viruses is a completely different form of living organisms. Viruses keep aloof in the world; they stay on the border between “living organisms” and “complex chemical molecules”. They don’t have the cell structure and include themselves in the cell fusion process when entering a body, thereby starting a disease. To fight them people use antiviral medications.


Vaccination, properly speaking, is not a medicine. It is an attenuated strain of pathogenic microorganisms, which causes the body to produce specific for a given disease antibodies, once inside. The development of the immune mechanism is triggered.


Vitamins can also be natural and synthetic. This is a completely separate group of medicine, designed to activate the “healthy scenario” of body’s metabolism. As for all other substances entering the body, a medical principle of “do no harm” is important for them. Their abundance, as well as lacking, can lead to diseases. Let’s examine vitamin C as an example. Its deficit can cause scurvy – a very dangerous, hard passing illness. But its excess also backfires as indigestion and other symptoms of poisoning.


That is why vitamins are appointed in courses – certain “portions” during some time.

Homeopathic medicines differ from traditional medication in the very principle of their operation. They don’t cut symptoms short and eliminate a cause a disease. A small dose of active substance (this is how very small concentrations are usually called – homeopathic) causes symptoms similar to the symptoms of the disease. Consistent long-term low-dose exposure activates the body's defense mechanisms. The principle of homeopathy: “like cures like”. Usually, in the basis of such drugs extracts and exudates of medicinal plants are used.


Once in the body, the drug passes through the whole digestive system. In the intestines, the mechanism of “suction” is activated, what allows a drug to influence the desired group of cells, organ or tissue.


A medication is a substance or mixture of substances of synthetic or natural origin, in the form of pills, capsules, solutions, ointments, used for the treatment or prevention of diseases.

In terms of chemistry, when the drug is ingested, curiously enough, no biochemical reactions occur – only chemical and physicochemical. The drug interacts with the “target” – the substance of the body which it has to affect (it can be protein, a receptor, an enzyme).


Because of the interaction of medicine and target a chemical bond is formed. Covalent bond is an example of such bond. Using this bond exactly is how cancer drugs work. Covalent bond is the chemical bond, formed by overlap (socialization) of a pair of valence electron clouds. Electron clouds, providing the bond, are called shared electron pairs. Such medication “binds” the tumor’s protein cells, destructing them:


Physicochemical interaction is represented by redox processes. Drugs using this type of influence have selectivity. Selectivity is ability to produce a reaction only with certain type of molecules (in pharmacology they are called receptors). Spatial form is also vital for a remedy. It is represented by spatial isomerism of molecules – spatial orientation of molecules. This is a typical type of isomerism of organic compounds and it is explained, first of all, by an opportunity for the substituents to position themselves differently with respect to the carbon atom (or a double bond):


Pharmacokinetics describes how exactly the interaction of medication and “target” happens in time. Drugs are most often prescribed in courses: a doctor writes down the dosage of medicine and determines how often you should take it. The same approach is also important for vitamins. So, drugs or vitamins come inside the body in “portions”. The action of a drug can start immediately after the intake. And it may start after a while, when a certain amount of the substance will be “accumulated” in the body (cumulation of matter). The drug may even begin to act at the stage of removing it from the body, if it is stipulated by pharmaceutical product features.


Each dose of the medicament triggers a certain process in the body (as shown above). This process is the body's response to the introduction of the drug. Such responses are accumulated just like doses are. The accumulation of reactions lies at the very base of homeopathy, which envisages long-term treatment or prophylaxis.

There is another type of drugs – “placebo”. This, as doctors claim, is a dummy that does not contain a therapeutic agent. It is offered in two cases: when a psychological effect is needed (for example, if the larger dose of the drug is contraindicated), or in the case of fraud drug suppliers (when pills which have zero effect are sold like normal drugs).


So, for medication the balance between its excess and deficiency is very important measurement. The minimum amount of substance entering the body and having the effect is called a dose. In clinical practice dosage is usually calculated per unit weight of a patient. This is due to the fact that the “bigger” the body is the larger amount of medicines it can handle. Babies have less dosage and adults – greater.

Most often drugs are received in courses – sequential administration of several doses over a certain period time, which are capable of intensive integration into the chemical processes of the human body.


And some amount of medication lingers in the body. With every new pill the amount of “lingering dose” is increasing. This process is called the cumulative effect.

Mathematical formulas allow to “calculate” this effect:


For instance: paracetamol’s accepted cumulative coefficient is k = 1.1. Paracetamol is the active agent of a drug called “Panadol”. For children it is prescribed as suspension. For a six-month child’s one-time dose is 4 ml. The maximum number of doses per day can’t be higher than 4 (considering the advice of doctors and pharmacists). 5 ml of suspension contains 120 mg of the active substance (paracetamol). 90% of the drug is removed from the body in 24 hours.




This is why doctors give prescriptions so carefully, where they indicate, how much (how many mg) of substance, how many times a day, before or after a meal and for how many days you should take.


What amount of substance will be accumulated in the body if its cumulative effect is 1.2, and one-time dose is 54 mg? Course consists of 5 admissions.

Nanotechnology has become a breakthrough in medicine and technology, reliable for thousands of patients. Nanotechnology studies structures, which do not cross the 100 nm (or even less) value in size, and operate with materials and equipment in these size ranges. Such sizes allow a medicine – nanomedicine to act strictly as intended, to interact exclusively with a “target” and not to engage in other processes in the body.

Nanomedicine is especially prospective in treating tumors – cancer.

Nanomedicine of the future will easily deliver active components through the barriers, surrounding human brain, lungs, or through placenta. Usually, a nanomedicine consists of hollow synthetic spheres. The active agent is either put inside, or is sprayed across the particle itself, or is connected to the surface of the particle.


Until recently nano-particles had only been suitable for administration by injections, as they couldn’t pass through the cell barrier lining the gastrointestinal tract. Scientists have solved this problem. They drew attention to the way young children absorb antibodies from the mother's milk in order to strengthen the immune system. So, antibodies are attached to the “receptor” molecules on the surface of the intestinal wall cells. These are the “gates” that give access to the blood vessels. Thus, the obstacles to nanomedicine are almost overcome. Now it's up to clinical trials and introduction into medical practice.


The fact that wild and domestic animals treat themselves has long been known. The fact that moles, ants and drosophila are engaged in self-treatment has a paramount importance for the ecology and evolution of the relationship parasite – host.

In nature there are a lot of species of medicinal plants (including poisonous) used by animals for treatment. The natural instinct teaches animals to fight their ailments with the help of representatives of the kingdom of medicinal flora. For example, lily of the valley is a favorite dainty of a dappled deer.


Sparrows and finches pick viburnum and carry it to their nests as a medicine and food.


Red wood ants add antibacterial resin of coniferous trees to the construction of their nests to prevent the growth of microbes in colonies.


Honeybees, just like ants, use vegetable gums with antibiotic properties in the construction of hives.

Parasitized monarch butterfly protects its progeny from the transmission of pathogen by laying eggs on milkweed leaves, whose juice owns antiparasitic properties.


By watching animals, their “medications” can be used to try in human pharmacology as well. Of course, only after proper research and clinical testing.


What other “animal – medical plant” bonds do you know?


The pharmaceutical business is one of the most profitable in the world, because people buy drugs in the first place. This means that the demand for drugs exists and always will, and this is reflected in their prices. However, let’s not forget that pharmaceutical companies spend huge amounts of money on research work on “inventing” drugs, their manufacture and practical testing, which can last from five to ten years. And it often happens that years of work and billions of dollars are wasted if medicines don’t pass clinical trials. Nevertheless, the variety of drugs that we see in drugstores, gives a reason to believe this industry will always be profitable.


Thereby, not only pharmaceutical business is associated with drugs, but also drugstore and logistics business, and manufacture or collection of raw materials. Their contribution to the resulting costs of drugs is also palpable.

Lesson summary:




The results of the case-lesson can be complemented with findings of students



What three websites have helped find important information?



To help student and couch:






Where can you get information for the case?









Location of the lesson:

The case-lesson takes place in the classroom. It is possible to conduct the lesson at museum or library.



Teams of boys and girls.

The score was:….


  • What amount of active substance is contained in 450 ml of medication, if in 5 ml it is 58 mg?
  • What amount of this substance will be accumulated in the body in 3 days if it is administered 2 times a day (cumulative coefficient is 0.98)? 99% of this substance is removed from the body in one day.



Formulate 5 questions to the case (an individual task).



90 min (double lesson)  


The possibility to conduct the lesson with a student-understudy:



The acquired knowledge and developed competence:

Knowledge about chemical and physicochemical working principles of drugs and vitamins.

Knowledge about biological peculiarities ofpharmaceutical medicine.

Acquiring practical skills of application of the received information.

Acquiring concrete knowledge in biology, chemistry, zoology and other branches (given in the scans).



Tags: medication, antibiotics, strains, penicillin, viruses, immune system, vitamins, chemical bond, selectivity, covalent bond, pharmacokinetics, dose, cumulative effect, nanomedicine.



Hrabowska Larysa Leonidivna


Participated in the case upgrading:


The End

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