Types of Drugs

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An Introduction to Drug Chemical Agents

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A drug is any chemical substance that brings about changes in the functioning of living organisms. Pharmacology is the science that studies and deals with drugs in medicines and their mechanism of action, physical and chemical properties, metabolism toxicity and therapeutics. Principles of drug action and different types of drugs are used in the treatment and prevention of diseases in human beings

A branch of medicine and pharmaceutical sciences concerned with drugs or the aftereffect of medicine, where a drug may be defined as any artificial, natural, or endogenous molecule which exerts a physiological or biochemical effect on the cell, tissue, or organ of the body. To be more specific we can say that it is the study of the interactions that occur between a living organism and chemicals that affect biochemical processes. Substances possessing medicinal properties are considered pharmaceuticals.

Types of Pharmacology

Pharmacology has the following Branches:

1. Pharmacokinetics: It describes what our body does to a drug, referring to the movement of the drug in our body, through the body and out of the body. This process usually occurs in 4 phases in pharmacokinetics. 

  • Absorption

  • Distribution

  • Metabolism 

  • Excretion 

Sometimes known by the acronym 'ADME'.

2. Pharmacodynamics: It is just the opposite of what pharmacokinetics is, it describes what a drug does to our body or how our body responds to the drug. 

The study of the physiological, molecular and biochemical effects of drugs on the human body involves the study of post-receptor effects, chemical interactions and receptor bindings. Together pharmacokinetics and pharmacodynamics build a dose-response relationship.

Types of Drugs and Their Uses

Medicinal drugs are chemical drugs divided into different groups or classes based on their uses, chemical structure or mode of action. These classification systems are sometimes confusing as one drug type may be included in more than one class. 

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Antimicrobial Drugs: Drugs are used for the prevention or treatment of diseases caused by microbes like bacteria, fungi, protozoa, viruses or helminths. They contain chemical substances which kill or reduce the metabolic products produced by the microorganisms. Antibiotics come under the category of antimicrobial drugs. Example- penicillin.

Immunosuppressants: Immunosuppressants are a group of medicines used to block the immune response and are generally administered to patients who have undergone organ transplantation or are suffering from an autoimmune disease. Some of the common immunosuppressants are drugs that contain polyclonal antibodies, monoclonal antibodies, glucocorticoids, etc.

Drugs that Affect Blood: There are drugs that have to activate or inhibit enzymes that are involved in the regulation of blood clotting within the blood vessels. These drugs are administered in conditions like atherosclerosis or any kind of blockage in arteries occurring in the blood flow. There are various drugs like anticoagulants, antiplatelet drugs and fibrinolytic drugs which are involved in controlling the coagulation process.

Cardiovascular Drugs: These affect the functioning of the heart and blood vessels. They are administered for cardiovascular diseases like hypertension, and atherosclerosis. These drugs also affect the functioning of the heart muscles, frequency and regularity of heartbeat, etc. 

Endocrine Drugs: Drugs that are used to treat endocrine abnormalities. Their functioning includes changes in the regulation of the hormonal axis, effects on hormonal transport, as well as similar changes to counter-regulatory hormone systems. Endocrine drugs are used for the treatment of thyroid, Addison disease, etc.

Reproductive Drugs: These affect the functioning of our reproductive system. These drugs are used for treating reproductive diseases. 

Central nervous system drugs: These affect the functioning of the central nervous system. These drugs are administered in order to produce changes in behaviour, a physical sensation or mental state. Local anaesthetics, on the other hand, induce a loss of sensation in just one area of the body by blocking conduction in nerves at and near the injection site.

Digestive System Drugs:  These groups of drugs act on the digestive system by affecting the actions of the involuntary muscle (motility) and thus altering movement or also by altering the secretion of digestive juices or gastric emptying. Examples of major groups of digestive drugs include antidiarrheal drugs, laxatives, antiemetics, emetics, proton pump inhibitors, and antacids.

Dermatologic Drugs: Topical application of drugs provides a direct, localized effect on a specific area of the skin. When these drugs are applied to the skin, they may be dissolved in a variety of formulations, ranging from simple solutions to greasy ointments. These medications can relieve itching, exert a constricting or astringent action on the pores, or dissolve or remove the epidermal layers. The skin can be affected by other means like photosensitizing drugs, and pigmenting agents (psoralens).

The chemical drugs list can be endless. There are numerous drugs for various diseases. These drugs are of vital importance to humankind. The knowledge of pharmacology and drugs is also indispensable to medical science. It helps create wonders in the human body and soothe numerous ailments. 

Did You Know?

Drugs are often abused by people. Adolescence is a period when a lot of people indulge in drug abuse and dependency. This can be due to experimentation, curiosity or even depression. This can cause serious issues which lead to severe consequences and even death. Drugs abused are opioids, cannabinoids, coca alkaloids, etc. These when taken in overdose can cause life-threatening damages.

FAQ (Frequently Asked Questions)

1. How drugs can be Grouped? What are the Various Groups of Drugs?

Ans: Various groups of drugs and examples exist in the pharmacological field. These are grouped based on their mode or mechanism of action, chemical composition, uses, etc. The classification helps in research related to this field and also eases work for medical practitioners. Drugs are also grouped according to diseases or human tissues or organs they act upon. 

2. What are the Effects of Drug Abuse? How many Types of Drugs are Abused?

Ans: Drugs have adverse effects on the human body. It starts with reckless behaviour, vandalism and violence. There can be life-threatening chances of coma and death in case of a drug overdose. There have been instances of death due to respiratory failure, cerebral haemorrhage or heart attacks. In teenagers, drug abuse leads to a drop in academic performance, isolation, depression, rebellious behaviour, loss of interest and hobbies, loss of appetite, weight fluctuations, change in sleeping habits, etc. Numerous drugs abused some of the common ones being marijuana, cocaine, valium, heroin, etc.