What are drugs?
A drug is defined as a chemical substance pharmaceutically that is made of known structure and has biological effects when one administers into a living organism. Another term for a drug is also known as medication or is commonly called a medicine. This pharmaceutical drug is used to treat patients, cure them of their diseases and also diagnosing disease for further treatment and pharmaceutical drug, also called a medication or medicine, is a chemical substance used to treat, cure, prevent, or diagnose a disease or for the promotion of their well-being.
Types of drugs
Based on the structure of the chemicals, pharmaceuticals have been categorized into the following:
- Small moleculesdrugs : These are organic molecules that are low in weight and are commonly synthesized using manufacturing protocols that are chemical-based. The ability of these particular drugs is regulation of biological processes by attaching to important biological enzymes and macromolecules inside the diseased body and also alteration of biological pathways responsible for the symptoms of an ailment or clinical condition.
- Biologics: These are biological originated entities that are macromolecular which are often extracted or synthesized partially from biological sources. Gene therapies, antibodies, vaccines, hormone replacement therapies, etc., are examples of these.
In addition to the above, drugs that are based on the mode of action are classified as follows:
- Physically acting drugs: These types of drugs do not react when exposed to any biological molecules or mediator inside the body. Instead, the benefits of these drugs are noticed by their bare presence where the action is taking place. Some examples of these include charcoal which is an antidote for certain types of poisoning and bisacodyl which binds itself to the surfaces of peptic ulcer in turn protecting the particular region against additional exposure to gastric acids.
- Chemically acting drugs: This category of drugs is usually known to chemically react with biological mediators or targets. Examples of such are antacid tablets that contain aluminum hydroxide and magnesium hydroxide in which its reaction with excess acid inside the stomach neutralizes it and lastly, chelating agents which act as neutralizers by chelating metal ions and eliminating the effects of harmful metals.
- Drugs that cause psychological modifications: These drugs can cause psychological changes within the body. This is done so to provide comfort for patients suffering from disease-related symptoms. The following categorization of these drugs is dependent on the various types of psychological effects induced in the patients:
- Drugs causing an action that is opposite to the neutral system: Let us then consider Loperamide which is an opioid where the drug is used to regulate and reduce diarrhea frequency. Due to its nature of being an agonist of opioid-receptor, it acts on μ-opioid receptors that are present in the myenteric plexus which is part of the large intestine. This reaction slows down the movements of the colonic mass and subdues the gastrocolic reflex.
- Drugs that cause-related effects: For instance, diuretics reduce blood pressure by decreasing the blood volume through the increase of urine excretion.
- Drugs that induce unrelated effects: Counter-irritants, commonly known as rubefacients, relieve pain by increasing blood circulation through the action of irritating the applied area.
- Drugs that act through receptors: anxiety drugs and antidepressants provide relief from symptoms associated with diseases by binding to the cell receptors which, in turn, brings changes at a cellular level.
- Drugs that act through replacement: Anti-Parkinsons’ drugs and antiepileptics that have similar neurotransmitter structures regulate the imbalance of the various disease-associated transmitters.
- Drugs that act by the process of substitution: Drugs that are based on this process are antibiotic, antiviral and anticancer drugs which adding a molecule that is functionless in place of a vital metabolite of the cell physiology which effectively causes the death and decay of bacteria, virus and cancer cells.
Pharmaceutic drugs can also be further classified based on the accessibility by patients. These are listed as follows:
- Prescription Drugs: These drugs can only be prescribed by a doctor or a licensed medical professional. These drugs are should also be approved by a regulatory authority in which these drugs can only be obtained from a registered pharmacy.
- Over the counter drugs: These drugs are easily accessible and do not require any sort of prescription.
Lastly, based on marketing and branding, pharmaceutical drugs can be categorized as the following:
- Branded/Innovative Drugs: Patent protected drugs can be developed, manufactured and sold only by the company or its subsidiaries that are in partnership with the company.
- Generic Drug Products: These types of drugs are made as well as distributed after a pharmacological interference loses its marketing exclusivity. These drugs are much cheaper as compared to branded products.
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