Editing Pharmacology (section)

==Divisions==
The discipline of pharmacology can be divided into many sub disciplines each with a specific focus.
[[File:Areas within Pharmacology.svg|thumb|Areas within Pharmacology]]
=== Systems of the body ===
[[Image:Pharmacologyprism.jpg|thumb|A variety of topics involved with pharmacology, including [[neuropharmacology]], renal pharmacology, human [[metabolism]], intracellular metabolism, and intracellular regulation]]
Pharmacology can also focus on specific [[Human body#Systems|systems]] comprising the body. Divisions related to bodily systems study the effects of drugs in different systems of the body. These include [[neuropharmacology]], in the [[central nervous system|central]] and [[peripheral nervous system]]s; [[immune system|immunopharmacology]] in the immune system. Other divisions include [[Circulatory system|cardiovascular]], [[renal system|renal]] and [[endocrine system|endocrine]] pharmacology. [[Psychopharmacology]] is the study of the use of drugs that affect the [[psyche (psychology)|psyche]], mind and behavior (e.g. antidepressants) in treating mental disorders (e.g. depression).<ref>{{cite web |title=Psychopharmacology |url=https://www.psychologytoday.com/us/basics/psychopharmacology |website=Psychology Today }}</ref><ref>{{cite web |title=What is Psychopharmacology |url=https://ascpp.org/resources/information-for-patients/what-is-psychopharmacology/ |website=American Society of Clinical Psychopharmacology |date=29 November 2012 }}</ref> It incorporates approaches and techniques from neuropharmacology, animal behavior and behavioral neuroscience, and is interested in the behavioral and neurobiological mechanisms of action of psychoactive drugs.{{Citation needed|date=July 2019}} The related field of [[neuropsychopharmacology]] focuses on the effects of drugs at the overlap between the nervous system and the psyche.<!-- Immuno: 3368
cardio: 1209
renal: 131
endocrine: 69 pubmed results in 2019--><!-- 27632 pubmed results in 2019-->

[[Pharmacometabolomics]], also known as pharmacometabonomics, is a field which stems from [[metabolomics]], the quantification and analysis of [[metabolites]] produced by the body.<ref name="daouk-weinshilboum2008" /><ref name="daouk-weinshilboum2014" /> It refers to the direct measurement of [[metabolites]] in an individual's bodily fluids, in order to predict or evaluate the [[metabolism]] of [[pharmaceutical]] compounds, and to better understand the pharmacokinetic profile of a drug.<ref name="daouk-weinshilboum2008" /><ref name="daouk-weinshilboum2014" /> Pharmacometabolomics can be applied to measure [[metabolite]] levels following the administration of a drug, in order to monitor the effects of the drug on metabolic pathways. [[Pharmacomicrobiomics]] studies the effect of microbiome variations on drug disposition, action, and toxicity.<ref>{{cite journal | vauthors = Rizkallah MR, Saad R, Aziz RK | title = The Human Microbiome Project, personalized medicine and the birth of pharmacomicrobiomics. | journal = Current Pharmacogenomics and Personalized Medicine | date = September 2010 | volume = 8 | issue = 3 | pages = 182–93 | doi = 10.2174/187569210792246326 }}</ref> Pharmacomicrobiomics is concerned with the interaction between drugs and the gut [[Microbiome of humans|microbiome]]. [[Pharmacogenomics]] is the application of genomic technologies to [[drug discovery]] and further characterization of drugs related to an organism's entire genome.{{Citation needed|date=July 2019}} For pharmacology regarding individual genes, [[pharmacogenetics]] studies how genetic variation gives rise to differing responses to drugs.{{Citation needed|date=July 2019}} [[Pharmacoepigenetics]] studies the underlying [[Epigenetics|epigenetic]] marking patterns that lead to variation in an individual's response to medical treatment.<ref>{{cite journal | vauthors = Gomez A, Ingelman-Sundberg M | title = Pharmacoepigenetics: its role in interindividual differences in drug response | journal = Clinical Pharmacology and Therapeutics | volume = 85 | issue = 4 | pages = 426–30 | date = April 2009 | pmid = 19242404 | doi = 10.1038/clpt.2009.2 }}</ref><!-- 11 pubmed results in 2019--><!-- pharmacometabolomics or pharmacometabonomics: 196 pubmed results in 2019--><!-- pharmacogenomics 24700 pubmed results in 2019--><!-- pharmacogenetics: 20383 pubmed results in 2019--><!-- pharmacoepigenetics: 56 pubmed results in 2019-->

===<span class="anchor" id="Posology"></span>Clinical practice and drug discovery===
{{main|Drug development|Drug Discovery Hit to Lead}}
[[File:Toxicology Research at FDA (NCTR 1193) (6009043040).jpg|thumb|right|255px|A [[Toxicology|toxicologist]] working in a lab]]
Pharmacology can be applied within clinical sciences. [[Clinical pharmacology]] is the application of pharmacological methods and principles in the study of drugs in humans.<ref>{{cite web|url=https://www.ascpt.org/Resources/Knowledge-Center/What-is-Clinical-Pharmacology|title=What is Clinical Pharmacology?|website=ascpt.org|access-date=31 October 2021|archive-date=31 October 2021|archive-url=https://web.archive.org/web/20211031021835/https://www.ascpt.org/Resources/Knowledge-Center/What-is-Clinical-Pharmacology|url-status=live}}</ref> An example of this is posology, which is the study of dosage of medicines.<ref>{{cite web|url=https://www.pharmamad.com/posology/|title=Posology, Factors Influencing Dose, Calculation of Doses|date=23 January 2019|access-date=31 October 2021|website=pharmamad.com|archive-date=31 October 2021|archive-url=https://web.archive.org/web/20211031021837/https://www.pharmamad.com/posology/|url-status=live}}</ref>

Pharmacology is closely related to [[toxicology]]. Both pharmacology and toxicology are scientific disciplines that focus on understanding the properties and actions of chemicals.<ref name="pharmtox">{{cite web|url=https://www.pharmtox.utoronto.ca/science-pharmacology-toxicology|title=The Science of Pharmacology & Toxicology|publisher=Faculty of Medicine, University of Toronto|access-date=July 16, 2019|archive-date=16 July 2019|archive-url=https://web.archive.org/web/20190716151155/https://www.pharmtox.utoronto.ca/science-pharmacology-toxicology|url-status=live}}</ref> However, pharmacology emphasizes the therapeutic effects of chemicals, usually drugs or compounds that could become drugs, whereas toxicology is the study of chemical's adverse effects and risk assessment.<ref name="pharmtox" />

Pharmacological knowledge is used to advise [[pharmacotherapy]] in [[medicine]] and [[pharmacy]].

==== Drug discovery ====
{{overly detailed|date=July 2019}}
[[Drug discovery]] is the field of study concerned with creating new drugs. It encompasses the subfields of [[drug design]] and [[Drug development|development]].{{fact|date=March 2025}} Drug discovery starts with drug design, which is the [[invention|inventive]] process of finding new drugs.<ref>{{cite book |doi=10.1201/b12381 |title=Textbook of Drug Design and Discovery |date=2002 |last1=Smith |first1=H. John |last2=Williams |first2=H. John |isbn=978-0-429-21928-3 |editor-first1=Tommy |editor-first2=Povl |editor-first3=Ulf |editor-last1=Liljefors |editor-last2=Krogsgaard-Larsen |editor-last3=Madsen }}{{pn|date=March 2025}}</ref> In the most basic sense, this involves the design of molecules that are complementary in [[shape]] and [[electric charge|charge]] to a given biomolecular target.<ref>{{cite web|url=https://www.chem.uwec.edu/Chem491_W09/Topic7-2.pdf|title=Introduction to Drug Design|access-date=31 October 2021|archive-date=31 October 2021|archive-url=https://web.archive.org/web/20211031021835/https://www.chem.uwec.edu/Chem491_W09/Topic7-2.pdf|url-status=live}}{{self-published inline|date=March 2025}}</ref> After a [[lead compound]] has been identified through drug discovery, drug development involves bringing the drug to the market.{{fact|date=March 2025}} Drug discovery is related to [[pharmacoeconomics]], which is the sub-discipline of [[health economics]] that considers the value of drugs.<ref>{{cite journal | vauthors = Mueller C, Schur C, O'Connell J | title = Prescription drug spending: the impact of age and chronic disease status | journal = American Journal of Public Health | volume = 87 | issue = 10 | pages = 1626–9 | date = October 1997 | pmid = 9357343 | pmc = 1381124 | doi = 10.2105/ajph.87.10.1626 }}</ref><ref>{{cite journal | vauthors = Arnold RJ, Ekins S | title = Time for cooperation in health economics among the modelling community | journal = PharmacoEconomics | volume = 28 | issue = 8 | pages = 609–13 | year = 2010 | pmid = 20513161 | doi = 10.2165/11537580-000000000-00000 }}</ref> Pharmacoeconomics evaluates the cost and benefits of drugs in order to guide optimal healthcare resource allocation.<ref>{{cite book |doi=10.1016/B978-0-12-802103-3.00034-1 |chapter=Pharmacoeconomics in Healthcare |title=Pharmaceutical Medicine and Translational Clinical Research |date=2018 |last1=Rai |first1=Mahendra |last2=Goyal |first2=Richa |pages=465–472 |isbn=978-0-12-802103-3 }}</ref> The techniques used for the [[Drug discovery|discovery]], [[Pharmaceutical formulation|formulation]], manufacturing and quality control of drugs discovery is studied by [[pharmaceutical engineering]], a branch of [[engineering]].<ref>{{cite journal| vauthors = Reklaitis GV, Khinast J, Muzzio F |date=November 2010|title=Pharmaceutical engineering science—New approaches to pharmaceutical development and manufacturing|journal=Chemical Engineering Science|volume=65|issue=21|pages=iv–vii|doi=10.1016/j.ces.2010.08.041|bibcode=2010ChEnS..65D...4R }}</ref> [[Safety pharmacology]] specialises in detecting and investigating potential undesirable effects of drugs.<ref>{{Cite journal|last=Hite|first=Mark|date=2016-06-25|title=Safety Pharmacology Approaches|journal=International Journal of Toxicology|language=en|volume=16|pages=23–32|doi=10.1080/109158197227332 |doi-access=free}}</ref><!-- drug discovery/design/development: 34092 pubmed results in 2019--><!-- pharmacoecon: 25523 pubmed results in 2019--><!-- pharmacoengineering or "pharmaceutical engineering" : 4830 pubmed results in 2019--><!-- safety pharm: 848 pubmed results in 2019-->{{AI4 | image = Drug discovery cycle.svg |class=skin-invert-image | image-bg-color = light-dark(white,transparent) | annotations = | align = right | image-width = 300 | width = 300 | height = 225 | alt = Drug discovery cycle schematic | caption =The drug discovery cycle}}

[[Drug development|Development of medication]] is a vital concern to [[medicine]], but also has strong [[economical]] and [[political]] implications. To protect the [[consumer]] and prevent abuse, many governments regulate the manufacture, sale, and administration of medication. In the [[United States]], the main body that regulates pharmaceuticals is the [[Food and Drug Administration]]; they enforce [[Technical standard|standards]] set by the [[United States Pharmacopoeia]]. In the [[European Union]], the main body that regulates pharmaceuticals is the [[European Medicines Agency|European Medicines Agency (EMA)]], and they enforce standards set by the [[European Pharmacopoeia]].

The metabolic stability and the reactivity of a library of candidate drug compounds have to be assessed for drug metabolism and toxicological studies. Many methods have been proposed for quantitative predictions in drug metabolism; one example of a recent computational method is SPORCalc.<ref>{{cite journal | vauthors = Smith J, Stein V | title = SPORCalc: A development of a database analysis that provides putative metabolic enzyme reactions for ligand-based drug design | journal = Computational Biology and Chemistry | volume = 33 | issue = 2 | pages = 149–59 | date = April 2009 | pmid = 19157988 | doi = 10.1016/j.compbiolchem.2008.11.002 }}</ref> A slight alteration to the chemical structure of a medicinal compound could alter its medicinal properties, depending on how the alteration relates to the structure of the substrate or receptor site on which it acts: this is called the structural activity relationship (SAR). When a useful activity has been identified, chemists will make many similar compounds called analogues, to try to maximize the desired medicinal effect(s). This can take anywhere from a few years to a decade or more, and is very expensive.<ref name="ReviseALChem">{{cite book |title=Revise A2 Chemistry |chapter=What's in a Medicine (WM) |chapter-url={{GBurl|4vtRp_03vFYC|pg=RA1-PA1}} |last1=Newton|first1=David| first2 = Alasdair | last2 = Thorpe | first3 = Chris | last3 = Otter | name-list-style = vanc |publisher=[[Heinemann Educational Publishers]]|year=2004|isbn=0-435-58347-6|pages=1}}</ref> One must also determine how safe the medicine is to consume, its stability in the human body and the best form for delivery to the desired organ system, such as tablet or aerosol. After extensive testing, which can take up to six years, the new medicine is ready for marketing and selling.<ref name="ReviseALChem" />

Because of these long timescales, and because out of every 5000 potential new medicines typically only one will ever reach the open market, this is an expensive way of doing things, often costing over 1 billion dollars. To recoup this outlay pharmaceutical companies may do a number of things:<ref name="ReviseALChem" />
* Carefully research the demand for their potential new product before spending an outlay of company funds.<ref name="ReviseALChem" />
* Obtain a patent on the new medicine preventing other companies from producing that medicine for a certain allocation of time.<ref name="ReviseALChem" />

The [[inverse benefit law]] describes the relationship between a drugs therapeutic benefits and its marketing.

When designing drugs, the [[placebo]] effect must be considered to assess the drug's true therapeutic value.

Drug development uses techniques from [[medicinal chemistry]] to chemically design drugs. This overlaps with the biological approach of finding targets and physiological effects.

=== Wider contexts ===
Pharmacology can be studied in relation to wider contexts than the physiology of individuals. For example, [[pharmacoepidemiology]] concerns the variations of the effects of drugs in or between populations, it is the bridge between [[clinical pharmacology]] and [[epidemiology]].<ref>{{Cite book |title=Rang and Dale's pharmacology |first1=James |last1=Ritter |first2=Rod J. |last2=Flower |first3=G. |last3=Henderson |first4=David J. |last4=MacEwan |first5=Yoon Kong |last5=Loke |first6=H. P. |last6=Rang |publisher=Elsevier |year=2020|isbn=978-0-7020-8060-9|edition=Ninth|location=Edinburgh|oclc=1081403059}}{{pn|date=March 2025}}</ref><ref>{{cite book |doi=10.1002/9781119701101.ch2 |chapter=Study Designs Available for Pharmacoepidemiologic Studies |title=Textbook of Pharmacoepidemiology |date=2021 |last1=Strom |first1=Brian L. |pages=20–34 |isbn=978-1-119-70107-1 }}</ref> [[Pharmacoenvironmentology]] or environmental pharmacology is the study of the effects of used pharmaceuticals and personal care products (PPCPs) on the environment after their elimination from the body.<ref>{{cite journal | vauthors = Rahman SZ, Khan RA, Gupta V, Uddin M | title = Pharmacoenvironmentology--a component of pharmacovigilance | journal = Environmental Health | volume = 6 | issue = 1 | pages = 20 | date = July 2007 | pmid = 17650313 | pmc = 1947975 | doi = 10.1186/1476-069X-6-20 | bibcode = 2007EnvHe...6...20R | doi-access = free }}</ref> Human health and ecology are intimately related so environmental pharmacology studies the environmental effect of drugs and [[pharmaceuticals and personal care products in the environment]].<ref>{{cite journal |last1=Jena |first1=Monalisa |last2=Mishra |first2=Archana |last3=Maiti |first3=Rituparna |title=Environmental pharmacology: source, impact and solution |journal=Reviews on Environmental Health |date=26 March 2019 |volume=34 |issue=1 |pages=69–79 |doi=10.1515/reveh-2018-0049 |pmid=30854834 |bibcode=2019RvEH...34...69J }}</ref>

Drugs may also have ethnocultural importance, so [[ethnopharmacology]] studies the ethnic and cultural aspects of pharmacology.<ref name="int-soc-ethnopharm">{{Cite web|title=International Society for Ethnopharmacology|url=https://ethnopharmacology.org/|access-date=2021-02-04|website=International Society for Ethnopharmacology|language=en-US|archive-date=21 January 2021|archive-url=https://web.archive.org/web/20210121205853/https://ethnopharmacology.org/|url-status=live}}</ref> <!-- pharmacoepidem: 8974 pubmed results in 2019--><!-- environmental pharm: 22 pubmed results in 2019-->

=== Emerging fields ===
[[Photopharmacology]] is an emerging approach in [[medicine]] in which drugs are activated and deactivated with [[light]]. The energy of light is used to change for shape and chemical properties of the drug, resulting in different biological activity.<ref>{{cite journal |last1=Ricart-Ortega |first1=Maria |last2=Font |first2=Joan |last3=Llebaria |first3=Amadeu |title=GPCR photopharmacology |journal=Molecular and Cellular Endocrinology |date=May 2019 |volume=488 |pages=36–51 |doi=10.1016/j.mce.2019.03.003 |pmid=30862498 |hdl=10261/201805 |hdl-access=free }}</ref> This is done to ultimately achieve control when and where drugs are active in a reversible manner, to prevent [[side effect]]s and pollution of drugs into the environment.<ref>{{cite journal |last1=Velema |first1=Willem A. |last2=Szymanski |first2=Wiktor |last3=Feringa |first3=Ben L. |title=Photopharmacology: Beyond Proof of Principle |journal=Journal of the American Chemical Society |date=12 February 2014 |volume=136 |issue=6 |pages=2178–2191 |doi=10.1021/ja413063e |pmid=24456115 |bibcode=2014JAChS.136.2178V |url=https://pure.rug.nl/ws/files/13153399/ja_2013_13063e_photopharma_revised.pdf }}</ref><ref>{{cite journal | vauthors = Broichhagen J, Frank JA, Trauner D | title = A roadmap to success in photopharmacology | journal = Accounts of Chemical Research | volume = 48 | issue = 7 | pages = 1947–60 | date = July 2015 | pmid = 26103428 | doi = 10.1021/acs.accounts.5b00129 }}</ref><!-- 28 pubmed results in 2019: Pharmacocybernetics or pharma-cybernetics or "cybernetic pharmacy" or cyberpharmacy
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