Notes On Drugs: Classification - CBSE Class 12 Chemistry
Chemistry influences every aspect of human life: the cleansing agents, clothes, food or the medicines, explosives, fuels, rocket propellants...etc Chemical reactions are the basis of life on earth, and that all activities are controlled by chemicals. Drugs are chemicals of low molecular masses that interact with macromolecular targets and produce a biological response.                Drug            +        Molecular target             →            Biological response (low molecular masses)        (Macromolecules) When the biological response is therapeutic, which are desired and beneficial, called as medicines. The use of chemicals for obtaining a therapeutic effect is called chemotherapy. When drugs are taken in safe dosages, they act as medicines and are useful in the diagnosis, prevention and treatment of diseases. When the same drugs are consumed in excess, they act as potential poisons. Classification of Drugs: → Pharmacological effect → Drug action → Chemical structure → Molecular targets Drugs can be classified on the basis of their pharmacological effect, drug action, chemical structure and molecular targets. Drugs classified on the basis of their biological (or) pharmacological effects are useful in treating a particular type of problem. Ex: Analgesics have a pain-killing effect, whereas antiseptics kill (or) arrest the growth of harmful micro-organisms. Drugs can also be classified on the basis of their action on a particular biochemical process. Ex: Antihistamines inhibit the action of the inflammation-causing compound, histamine. Drugs classified according to their chemical structure share common structural features and often have similar pharmacological activity. Ex: All sulphonamides have a common structural feature. Sulphonamides are anti-bacterial drugs used to treat bacterial infections. Drugs usually interact with bio-molecules like carbohydrates, lipids, protein and nucleic acids. These bio-molecules are called drug targets (or) simply target molecules. Drugs with similar structures have similar mechanisms of action on bio-molecular targets. Drugs classified as per their molecular targets are especially used in the treatment of major ailments such as cancer and tumours.

#### Summary

Chemistry influences every aspect of human life: the cleansing agents, clothes, food or the medicines, explosives, fuels, rocket propellants...etc Chemical reactions are the basis of life on earth, and that all activities are controlled by chemicals. Drugs are chemicals of low molecular masses that interact with macromolecular targets and produce a biological response.                Drug            +        Molecular target             →            Biological response (low molecular masses)        (Macromolecules) When the biological response is therapeutic, which are desired and beneficial, called as medicines. The use of chemicals for obtaining a therapeutic effect is called chemotherapy. When drugs are taken in safe dosages, they act as medicines and are useful in the diagnosis, prevention and treatment of diseases. When the same drugs are consumed in excess, they act as potential poisons. Classification of Drugs: → Pharmacological effect → Drug action → Chemical structure → Molecular targets Drugs can be classified on the basis of their pharmacological effect, drug action, chemical structure and molecular targets. Drugs classified on the basis of their biological (or) pharmacological effects are useful in treating a particular type of problem. Ex: Analgesics have a pain-killing effect, whereas antiseptics kill (or) arrest the growth of harmful micro-organisms. Drugs can also be classified on the basis of their action on a particular biochemical process. Ex: Antihistamines inhibit the action of the inflammation-causing compound, histamine. Drugs classified according to their chemical structure share common structural features and often have similar pharmacological activity. Ex: All sulphonamides have a common structural feature. Sulphonamides are anti-bacterial drugs used to treat bacterial infections. Drugs usually interact with bio-molecules like carbohydrates, lipids, protein and nucleic acids. These bio-molecules are called drug targets (or) simply target molecules. Drugs with similar structures have similar mechanisms of action on bio-molecular targets. Drugs classified as per their molecular targets are especially used in the treatment of major ailments such as cancer and tumours.

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