IN modern world There is a huge number medicines. In addition, each of them has specific physical and chemical propertiesThey are still participants in certain reactions in the body. So, for example, with simultaneous use of two or more drugs, they can enter into interaction with each other. This can lead both to a mutual strengthening of one or both of the means (synergism) and to their weakening (antagonism).

Below will be described in detail the second type of interaction. So, antagonism in pharmacology. What is it?

Description of this phenomenon

The definition of antagonism in pharmacology happened from Greek: Anti - against, Agon - struggle.

This type at which weakening or disappearance occurs therapeutic effect One or each of them. In this case, substances are divided into two groups.

1. Agonists - those that, when interacting with biological receptors, receive a response from them, thereby providing its effect on the body.
2. Antagonists - those that are unable to independently stimulate receptors, as they have zero internal activity. The pharmacological effect of such substances is due to interaction with agonists or mediators, hormones. They can occupy both the same receptors and different.

Talk about antagonism only in case accurate dosages and specific pharmacological effects of drugs. For example, with their other quantitative ratio, weakening or complete absence of one or everyone can occur, and may, on the contrary, their amplification (synergism) occur.

An accurate assessment of the degree of antagonism can be given only by building graphs. This method clearly demonstrates the relationship between substances from their concentration in the body.

Types of interaction of drugs with each other

Depending on the mechanism, there are several types of antagonism in pharmacology:

• physical;
• chemical;
• functional.

Physical antagonism in pharmacology - the interaction of drugs among themselves is due to their physical properties. For example, activated carbon - absorbent. In case of poisoning with any chemicals, the use of coal neutralizes their action and derives toxins from the intestine.

Chemical antagonism in pharmacology - the interaction of drugs is due to the fact that they enter into chemical reactions with each other. This type has found great use in the treatment of poisoning with various substances.

For example, in the poisoning of cyanides and the introduction of sodium thiosulfate, the process of sulphing first occurs. As a result, they turn into a less dangerous for the body of rodanides.

The second example: when poisoning with heavy metals (arsenic, mercury, cadmium and others), "cysteine" or "unitiol" are used, which neutralize them.

The types of antagonism listed above combines that they are based on processes that can flow both inside the body and in the environment.

Functional antagonism in pharmacology differs from the two previous ones that it is possible only in the human body.

This appearance is divided into two subspecies:

• indirect (indirect);
• direct antagonism.

In the first case, drugs have an impact on different cell elements, but one eliminates the other effect.

For example: strip-like drugs ("Tubokuran", "dithiline") affect skeletal muscles through cholinoreceptors, while they eliminate the convulsions that are by-effect Strichnina on neurons spinal cord.

Direct antagonism in pharmacology

This species requires a more detailed study, as includes many different options.

In this case, drugs act on the same cells, thereby suppressing each other. Direct functional antagonism is divided into several subspecies:

• competitive;
• non-equivous;
• not competitive;
• independent.

Competitive antagonism

Both substances interact with the same receptors, while speaking with each other rivals. The more molecules of one substance contact the cells of the body, the less receptors will be able to occupy the molecules of the other.

Lots of medicinal preparations They enter into competitive direct antagonism. For example, Dimedrol and Histamine interact with one n-histamine receptors, while they are competitors for each other. The situation with pairs of substances is similar:

• sulfanimamides (Biseptol, Bactrim) and (abbreviated: PABK);
• fentolamine - adrenaline and norepinephrine;
• hyoscyamine and Atropine - acetyl-choline.

In the examples listed, one of the substances is a metabolite. However, competitive antagonism is possible in cases where none of the compounds will not be. For example:

• "Atropine" - "Pilocarpine";
• "Tubokuran" - "Ditilin".

The mechanisms of action of many drugs lies and antagonistic relations with other substances. So sulfonamides, competing with PABK, have an antimicrobial effect on the body.

The blocking of Holine receptors "Atropine", "dilative" and some other drugs is explained by the fact that they compete with acetylcholine in synapses.

Many drugs are classified based on their belonging to antagonists.

Nonavilibrium antagonism

With non-equilibrium antagonism, two drugs (agonist and antagonist) also interact with the same bioreceptors, but the interaction of one of the substances is practically irreversibly, since after this the activity of receptors is significantly reduced.

The second substance fails to successfully interact with them, in any amount he neither tried to have the effect. This is this type of antagonism in pharmacology.

An example, which is the most bright in this case: Dibenamine (as an antagonist) and norepinephrine or histamine (as agonists). In the presence of the first, the second is not able to provide its maximum effect even with very high dosages.

Non-competitive antagonism

Non-competitive antagonism is that one of the drugs interacts with the receptor outside its active center. As a result, the efficiency of interaction with these second-product receptors is reduced.

An example of such a ratio of substances is the effect of histamine and beta-adreminimetics on the smooth muscles of the bronchi. Histamine excites H1 cell receptors, thereby causing the narrowing of the bronchi. Beta adreminimetics (Salbutamol, Dopamine) act on beta-adrenoreceptors and cause expansion of bronchi.

Independent antagonism

With independent antagonism, medicinal substances act on different cell receptors, changing its function in opposite directions. For example, the spasm of smooth muscles caused by carbacholine as a result of its impact on M-cholinoreceptors of muscle fibers, decreases with adrenaline, relaxing smooth muscles through adrenoreceptors.

Conclusion

It is extremely important to know what it is antagonism. In pharmacology there are many types of antagonistic relations between drugs. It is necessary to take into account doctors while prescribing to the patient of several drugs and the provision (or pharmacist) when they are vacated from the pharmacy. This will help avoid unforeseen consequences. Therefore, in the instructions for the use of any medication there is always a separate clause on interaction with other substances.

Animals, plants, as well as microorganisms there is something in common - this desire to survive. Therefore, many types of interactions between alive organisms are antagonistic. Find out what it means, and what types of antagonism exist.

What is antagonism?

Do you have an annoying younger brother who antagonize you? If not, just imagine a similar situation. What makes your brother or sister to annoy you? He / she probably makes your life more difficult. It is not too far from the concept of antagonism, since it is associated with natural selection and.

Since the organisms themselves are concentrated sources of energy and nutrients, they can become antagonistic relationships. Although antagonism is usually considered as an association between various speciesIt can also arise between members of the same species through competition and cannibalism.

Types of antagonism

Exist different types Antagonism. Let's look at some of them:

Predation

An excellent example of predation is a flock of wolves, pursuing a deer. Deer is just one big power source. Wolves eat deer and get nutrients that support their lives. If the deer hits the wolves, he may be able to multiply and convey to the next generation. In the case when the wolves overtake the deer, they get food and chance to transfer their genes instead.

Competition

Competition is a negative relationship between organisms that need the same. For example, plants (even one species) growing in a small area can compete for sunlight or mineral substances in the soil. Some plants will be able to eradicate others to survive and multiply, while others will be cleaned.

Cannibalism

Another type of antagonism is cannibalism, when one animal eats another animal of its kind. For some species, cannibalism is an extremely rare practice that is used in extreme survival situations, for example, mother-mouse eats their cubs to escape from hungry death.

Other examples of antagonism

Antagonistic interactions may also include protective strategies using chemical and physical deterrent factors. Many plant species are able to allocate chemicals into the soil to impede the growth of other plants or protect against insects and grazing animals.

Plants and animals develop physical adaptations, such as solid shell (Skin) and spikes to prevent the attacks of herbivores and. In addition, some species have devices that provide them with similarities with others. Such adaptations can be used both for attack and protection.

Substances that, when interacting with specific receptors, cause changes to them leading to biological effect, called agonists. The stimulating effect of agonist on receptors can lead to activation or inhibition of the cell function. If the agonist, interacting with the receptors, causes the maximum effect, then this is a complete agonist. Unlike the latter, partial agonists when interacting with the same receptors do not cause the maximum effect.

Substances binding to receptors, but not causing their stimulation, called antagonists. Their internal activity is zero. Them pharmacological effects Conducted by antagonism with endogenous ligands (mediators, hormones), as well as with exogenous agonist substances. If they occupy the same receptors with which the agonists interact, they are talking about competitive antagonists; if other sections of macromolecules not related to specific receptorBut interrelated with it, they speak of non-competitive antagonists.

If the substance acts as an agonist for one subtype of receptors and as an antagonist - to another, it is indicated as an antagonist agonist.

The so-called nonspecific receptors are isolated, binding to which substances do not cause effect (blood plasma proteins, mucopolysaccharides connective tissue); They are also called places of nonspecific binding of substances.

The interaction "substance-receptor" is carried out at the expense of intermolecular connections. One of the most durable types of communication is a covalent connection. It is known for a small amount of preparations (some antoblast substances). The less resistant is a more common ion connection, typical of gangliplockers and acetylcholine. Vanderwals (the basis of hydrophobic interactions) and hydrogen bonds play an important role.

Depending on the strength of the supply-receptor communication, the reversible action is characteristic of most substances, and irreversible action (in the case of a covalent bond).

If the substance interacts only with functionally unambiguous receptors of a certain localization and does not affect other receptors, the effect of such a substance is considered selective. The basis of the election of action is affinity (affinity) of the substance to the receptor.

Another important target medicinal substances are ion channels. Of particular interest is the search for blockers and activators of Ca 2+ - channels with predominant influence on the heart and vessels. In recent years, many attention is attracted to substances that regulate the function K + -Kanalov.

An important target of many medicinal substances are enzymes. For example, the mechanism of the action of non-steroidal anti-inflammatory means is due to the inhibition of cyclooxygenase and a decrease in the biosynthesis of foregnosity. The antiblastomine drug methotrexate blocks dihydrofolatide, preventing the formation of tetrahydrofolate necessary for the synthesis of purine nucleotide-thymidilate. The acyclovir inhibits the virus DNA polymerase.

Another possible target of medicines - transport systems for polar molecules, ions and small hydrophilic molecules. One of the latest achievements in this direction is the creation of propionic pump inhibitors in the gastric mucosa (omeprazole).

An important target of many medicinal substances are genes of genes. Research in the field of geminomacology is becoming more widespread.

Patients with inpatient treatment are prescribed from 4 to 6 to 10 drugs. Along with the means of therapy of the underlying disease, the drugs taken by the patient are composed of tall drugs, substances for the treatment of concomitant pathology and complications of the underlying disease. Combined drugs can interact as synergists, antagonists and synergo antagonists.

Synergism

Synergism (Greek. synergos -acting together) - strengthening the action of one drug to others. There are summable and potentiated synergism.

Summed synergism,or addian(Lat. adDitio -adding) - the effect of the combination is equal to the arithmetic amount of the effects of combined drugs. It is characteristic of drugs of one pharmacological groupinfluencing the same citrateceptors, cells, organs (synergism of common anesthetics for inhalation anesthesia, paracetamol and ibuprofen during chronic pain).

Potentiated synergism,or superaddia -the effect of the combination exceeds the arithmetic amount of the effects of combined drugs. Arises as a result of pharmacokinetic and pharmacodynamic mechanisms:

· A change in suction - adrenomimetics, narrowing vessels, prevent suction in the blood of local anesthetics with the strengthening of their local painkillers; substances that create an acidic medium in the digestive tract (acid ascorbic, acetylsalicyl) increase the absorption of drugs with the properties of weak acids (salicylates, indomethacin, furosemid, indirect effect anticoagulants, sulfonamides, tetracycline); In contrast, antacids, causing a pH shift in the alkaline side, activate the suction of the bases (alkaloids, tranquilizers, antiforms);

· Displacement of drugs due to blood proteins - anti-inflammatory agents Butadion and indomethacin are released from albumin anticoagulants and a sugar-imaging drug glibenklamide with the danger of bleeding and hypoglycemia;

· Improving the permeability of membranes - insulin facilitates the penetration of glucose and potassium ions through the cell membrane;

· Inhibition of metabolism - anticholinesterase agents are prolonged and enhance the effect of acetylcholine; Blocator Aldehydehydrogenase Teturas potentiates the effects of the alcohol of ethyl alcohol - acetic aldehyde; Inhibitors of cytochrome R-450.increase the effect of drugs having metabolic clearance;

· Impact of drugs on various systems for regulation of functions and cytimeceptors-synergists - potentiated anesthesia using muscle relaxants, tranquilizers, analgesics; Significant increase in the hypotensive effect of vasodilatory drugs with a joint appointment with diuretic.

Synergism is possible side Effects medicines. Thus, with the joint purpose of antibiotics-aminoglycosides (streptomycin, kanamycin, gentamicin) and diuretic drugs (furosemid, ethanin acid), the risk of output and vestibulus complications increases; The introduction of calcium chloride into the vein on the background of therapy with heart glycosides causes arrhythmia.

Antagonism

Antagonism is accompanied by a weakening of the action of one drug to others. There are several types of antagonism.

1. Physical antagonism- reduction of suction to blood and resorbative action:

· Adsorbents (coal activated, ion exchange resins of kolhesistramine) prevent the suction of many drugs taken inward; salt laxatives (magnesium and sodium sulfates), increasing the osmotic pressure in the intestinal list, delay the absorption of drugs dissolved in intestinal juice;

· Calcium, magnesium ions, iron are formed by unsustenting complexes with tetracycline, leftomycetin, sulfonamides, acid acetylsalicyl, butadion;

· Tools that create in the digestive tract with acid or alkali environment, the absorption of drugs with the properties of respectively bases or acids is inhibited;

· The adrenaline vesseloring agent reduces the absorption of drugs introduced under the skin or into the muscles.

2. Chemical antagonism -chemical interaction of medicines in the blood with the formation of inactive products. Chemical antagonists are potassium permanganate, sodium thiosulfate, donator sulfhydryl groups unitiol, complexation agents Danodium salt of ethylenediaminetetraacetic acid, thetacin calcium and other antidots used for poisoning therapy. For example, sodium thiosulfate translates toxic molecular iodine into non-toxic iodides, cyanides - in safe rodanids:

3. Physiological (functional) antagonism -the interaction of drugs that have a multidirectional effect on the function of cells and organs. Physiological antagonism is divided into indirect and straight:

· Indirect antagonism - the result of action on various cells (adrenaline adrenaline is expanding the pupils due to the reduction of the radial muscle of the iris, cholinomimet of acetylcholine narrows pupils, causing a reduction in circular muscle);

· Straight antagonism - the result of the action on the same cells: not competitive antagonism occurs when binding medicines with various citrateceptors, competitive antagonism - between agonists and antagonists of some cytoreceptors.

Examples of non-competitive antagonism - the narrowing of the bronchi histamine, exciting N. 1-receptors of smooth muscles, and the expansion of bronchi β-adrenomimetics; Antagonism between acetylcholinesterase blockers and cholinoreceptor blockers.

Competitive antagonists are M-cholinomimetics Pilocarpine and M-cholinoblocator Atropine; A-adrenomimetic norepinephrine and A-adrenoblocator fantolamine; Histamine and blocator N. 2 Ranitidine receptors.

Synergo antagonism

The synergo-antagonism implies a phenomenon when one effects of combined drugs are enhanced, while others are weakened. As part of the Tablets "Aeron", Skopolamine and Hyoscyamine - synergists at the inhibitory influence on the vomit. Skopolamine oppresses the respiratory center, on the contrary, Hyoscyamine it tones. A-adrenoblays weaken the hypertensive phase and enhance the anti-adrenaline hypotensive phase.