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	'''Pharmacology''' is the scientific study of medicines, drugs, and how they act in living systems. It looks at what a substance does to the body, what the body does to the substance, why effects vary between people, and how benefits are balanced against harms.

Pharmacology is the scientific study of how drugs interact with the body, their mechanisms of action, and their effects on physiological processes. It encompasses a broad range of disciplines, including biochemistry, physiology, molecular biology, and medicine, with the goal of understanding how drugs can be used to prevent, treat, or manage diseases and conditions.
	The field connects chemistry, biology, physiology, medicine, toxicology, pharmacy, and public health. It is central to drug discovery, safe prescribing, clinical trials, dose selection, medicine monitoring, and the study of unwanted effects.

== History and Development ==
The roots of pharmacology can be traced back to ancient civilizations, where herbal remedies and natural substances were used to alleviate ailments. As scientific knowledge advanced, the field of pharmacology evolved to include the study of chemical compounds, drug interactions, and the development of synthetic drugs.
	== Scope ==
	Pharmacology covers more than prescription medicines. It can include over-the-counter medicines, anaesthetic agents, vaccines, biological therapies, hormones, poisons, recreational drugs, herbal substances, and experimental compounds.

In modern times, pharmacology has become an integral part of medical and healthcare research, guiding the discovery and development of new drugs, optimizing their dosages, and understanding their potential side effects.
	The subject is usually divided into several overlapping areas:

== Drug Categories and Classification ==
Pharmacology classifies drugs into various categories based on their mechanisms of action and therapeutic uses. Some common drug categories include:
	* '''Pharmacodynamics''', which studies what a drug does to the body.
	* '''Pharmacokinetics''', which studies what the body does to a drug.
	* '''Clinical pharmacology''', which applies pharmacology to patient care and safe medicine use.
	* '''Toxicology''', which studies harmful effects of chemicals and drugs.
	* '''Pharmacogenetics''', which studies how genetic variation can affect drug response.
	* '''Pharmacovigilance''', which monitors medicine safety after use in the wider population.

=== 1. Analgesics: ===
Analgesics are drugs that provide pain relief by blocking pain signals or reducing pain perception. They include nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and acetaminophen.
	== Pharmacodynamics ==
	Pharmacodynamics deals with drug action. Many medicines work by binding to receptors, enzymes, transporters, ion channels, or other molecular targets. Binding may activate a target, block it, change a signalling pathway, replace a missing substance, or alter the behaviour of a cell.

=== 2. Antimicrobials: ===
Antimicrobial drugs combat infections caused by bacteria, viruses, fungi, and parasites. They include antibiotics, antivirals, antifungals, and antiparasitic agents.
	Important pharmacodynamic ideas include:

=== 3. Cardiovascular Agents: ===
These drugs affect the heart and blood vessels, regulating blood pressure, heart rate, and circulation. Examples include beta-blockers, calcium channel blockers, and anticoagulants.
	* '''Potency''': how much of a drug is needed to produce an effect.
	* '''Efficacy''': the maximum effect a drug can produce.
	* '''Selectivity''': how strongly a drug acts on the intended target compared with other targets.
	* '''Therapeutic window''': the range between a dose likely to work and a dose likely to cause unacceptable harm.
	* '''Tolerance''': reduced response after repeated exposure.

=== 4. Psychotropic Drugs: ===
Psychotropic drugs act on the central nervous system to manage mental health conditions. They include antidepressants, antipsychotics, anxiolytics, and mood stabilizers.
	Side effects often occur because a target exists in more than one tissue, because the drug binds to unintended targets, or because the intended effect has consequences elsewhere in the body.

== Pharmacokinetics and Pharmacodynamics ==
Pharmacology studies how drugs are absorbed, distributed, metabolized, and excreted by the body (pharmacokinetics) and how they exert their effects on cells and tissues (pharmacodynamics).
	== Pharmacokinetics ==
	Pharmacokinetics is often summarised as absorption, distribution, metabolism, and excretion.

=== Pharmacokinetics: ===
Pharmacokinetics explores processes such as absorption through the digestive tract, distribution via the bloodstream, metabolism in the liver, and elimination through urine and faeces. Factors like drug formulation, dosage, and individual patient characteristics influence pharmacokinetics.
	* '''Absorption''': how a drug enters the bloodstream or reaches its site of action.
	* '''Distribution''': how it moves through blood, tissues, organs, and body fluids.
	* '''Metabolism''': how enzymes, often in the liver, chemically change the drug.
	* '''Excretion''': how the drug or its metabolites leave the body, often through urine or bile.

=== Pharmacodynamics: ===
Pharmacodynamics focuses on how drugs interact with specific receptors on cells or affect biochemical pathways, leading to therapeutic or adverse effects. Understanding pharmacodynamics helps optimize drug dosages and minimize side effects.
	These processes affect dose, timing, route of administration, interactions, and the risk of accumulation. Kidney function, liver function, age, pregnancy, body size, other medicines, food, and genetics can all affect pharmacokinetics.

== Drug Development and Clinical Trials ==
The process of developing new drugs involves several stages, including drug discovery, preclinical testing, and clinical trials. Clinical trials involve testing drugs in controlled settings to evaluate their safety, efficacy, and potential side effects in humans. Regulatory authorities, such as the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK, oversee and approve new drug applications before they can be marketed.
	== Drug Classes ==
	Drug classes can be based on clinical use, chemical structure, or mechanism of action. Examples include:

== Personalized Medicine and Pharmacogenetics ==
Advances in pharmacology have led to the emergence of personalized medicine, which tailors drug treatments to an individual's genetic makeup and physiological characteristics. Pharmacogenetics studies how genetic variations influence drug responses, allowing healthcare providers to optimize drug selection and dosages for each patient.
	* '''Analgesics''', used to reduce pain.
	* '''Antibiotics''', used to treat bacterial infection.
	* '''Anticoagulants''', used to reduce unwanted blood clotting.
	* '''Antihypertensives''', used to treat high blood pressure.
	* '''Antivirals''', used against viral infections.
	* '''Bronchodilators''', used to widen airways.
	* '''Corticosteroids''', used to reduce inflammation or replace steroid hormones.
	* '''Vaccines''', used to prompt an immune response before exposure to a disease.

== Ethical Considerations ==
Pharmacology raises ethical concerns related to drug testing, patient safety, and the responsible use of medications. Researchers and healthcare professionals must balance the potential benefits of drugs with their risks and consider factors such as informed consent, patient autonomy, and equitable access to treatment.
	Class labels are useful, but they can hide important differences. Two medicines in the same class may have different risks, interactions, dose schedules, or approved uses.

== Conclusion ==
Pharmacology is a dynamic and multidisciplinary field that plays a crucial role in improving healthcare outcomes and advancing medical science. By understanding how drugs interact with the body and tailoring treatments to individual patients, pharmacologists contribute to the development of effective and safe therapies for a wide range of diseases and conditions.
	== Clinical Trials and Regulation ==
	New medicines are usually studied first in laboratory and pre-clinical work, then in staged clinical trials. Trials test safety, dose, effectiveness, side effects, interactions, and how the medicine compares with existing care or placebo where appropriate.

	In the UK, the Medicines and Healthcare products Regulatory Agency is the regulator for medicines and medical devices. A medicine normally needs evidence on quality, safety, and effectiveness before it can be supplied for routine use. After approval, safety monitoring continues because rare or long-term effects may only become clear when a medicine is used by larger and more varied groups of people.

	== Safe Use ==
	Safe medicine use depends on the medicine, the person taking it, and the setting. Pharmacology helps explain why the same drug may be suitable for one person but unsuitable for another.

	Factors that can change risk include:

	* Age and body weight.
	* Pregnancy or breastfeeding.
	* Kidney or liver impairment.
	* Allergies and previous adverse reactions.
	* Other medicines, supplements, alcohol, or recreational drugs.
	* The dose, route, and duration of treatment.

	Clear labelling, patient information leaflets, prescribing records, medication reviews, and adverse event reporting all support safer use.

== See Also ==	== See Also ==
	* [[Common_Medical_Terms]]
	* [[Vitamin_C]]
	* [[Omega-3_fatty_acids]]

* [[Pharmacokinetics]]
* [[Pharmacodynamics]]
* [[Drug Development]]
* [[Personalised Medicine]]
	== References ==
	* [https://www.bps.ac.uk/careers-education/what-is-pharmacology/ British Pharmacological Society: What is pharmacology]
	* [https://www.ncbi.nlm.nih.gov/books/NBK595006/ NCBI Bookshelf: Pharmacokinetics and pharmacodynamics]
	* [https://www.ncbi.nlm.nih.gov/books/NBK507791/ NCBI Bookshelf: Pharmacodynamics]
	* [https://www.ncbi.nlm.nih.gov/books/NBK557744/ NCBI Bookshelf: Pharmacokinetics]
	* [https://www.gov.uk/government/organisations/medicines-and-healthcare-products-regulatory-agency GOV.UK: MHRA]
	* [https://www.fda.gov/drugs/development-approval-process-drugs/how-drugs-are-developed-and-approved FDA: How drugs are developed and approved]

	[[Category:Medicine]]
	[[Category:Science]]