Editing Promethazine (section)

{{Short description|Sedating antihistamine}}
{{Use dmy dates|date=March 2024}}
{{cs1 config |name-list-style=vanc |display-authors=6}}
{{Drugbox
| Watchedfields      = changed
| verifiedrevid      = 462079943
| image              = Promethazine.svg
| image_class        = skin-invert-image
| width              = 150
| alt                = 
| image2             = Promethazine-based-on-xtal-3D-bs-17.png
| image_class2       = bg-transparent
| width2             = 175 <!-- image is quite low res, so don't over enlarge -->
| alt2               = 
| chirality          = [[Racemic mixture]]

<!-- Clinical data -->
| tradename          = Phenergan, others<ref name=brands/>
| Drugs.com          = {{drugs.com|monograph|promethazine-hydrochloride}}
| MedlinePlus        = a682284
| DailyMedID         = Promethazine
| pregnancy_AU       = C
| pregnancy_category = 
| routes_of_administration = [[By mouth]], [[rectal administration|rectal]], [[intravenous therapy|intravenous]], [[intramuscular injection|intramuscular]], [[topical administration|topical]]
| ATC_prefix         = D04
| ATC_suffix         = AA10
| ATC_supplemental   = {{ATC|R06|AD02}}
| legal_AU           = S3
| legal_CA           = OTC
| legal_UK           = P
| legal_UK_comment   = (POM when injection)
| legal_US           = Rx-only
| legal_status       = South Africa: S5 IV, S2 oral

<!-- Pharmacokinetic data -->| bioavailability    = 88% absorbed but after first-pass metabolism reduced to 25% absolute bioavailability<ref name="pmid10965395"/>
| protein_bound      = 93%
| metabolism         = [[Liver]] [[glucuronidation]] and [[sulfoxide|sulfoxidation]]
| elimination_half-life = 10–19 hours<ref name="pmid10965395" /><ref name="pmid2866055">{{cite journal |vauthors=Paton DM, Webster DR | title = Clinical pharmacokinetics of H1-receptor antagonists (the antihistamines) | journal = Clinical Pharmacokinetics | volume = 10 | issue = 6 | pages = 477–97 | year = 1985 | pmid = 2866055 | doi = 10.2165/00003088-198510060-00002| s2cid = 33541001 }}</ref>
| excretion          = [[Kidney]] and [[Bile duct]]

<!-- Identifiers -->| IUPHAR_ligand      = 7282
| CAS_number_Ref     = {{cascite|correct|??}}
| CAS_number         = 60-87-7
| CAS_supplemental   = <br/>{{CAS|58-33-3}} ([[hydrochloride|HCl]]) <!-- Also CAS verified -->
| PubChem            = 4927
| DrugBank_Ref       = {{drugbankcite|correct|drugbank}}
| DrugBank           = DB01069
| ChemSpiderID_Ref   = {{chemspidercite|correct|chemspider}}
| ChemSpiderID       = 4758
| UNII_Ref           = {{fdacite|correct|FDA}}
| UNII               = FF28EJQ494
| KEGG_Ref           = {{keggcite|correct|kegg}}
| KEGG               = D00494
| ChEBI_Ref          = {{ebicite|correct|EBI}}
| ChEBI              = 8461
| ChEMBL_Ref         = {{ebicite|correct|EBI}}
| ChEMBL             = 643

<!-- Chemical data -->| IUPAC_name         = (''RS'')-''N,N''-Dimethyl-1-(10''H''-phenothiazin-10-yl)propan-2-amine
| C                  = 17
| H                  = 20
| N                  = 2
| S                  = 1
| SMILES             = S2c1ccccc1N(c3c2cccc3)CC(N(C)C)C
| StdInChI_Ref       = {{stdinchicite|correct|chemspider}}
| StdInChI           = 1S/C17H20N2S/c1-13(18(2)3)12-19-14-8-4-6-10-16(14)20-17-11-7-5-9-15(17)19/h4-11,13H,12H2,1-3H3
| StdInChIKey_Ref    = {{stdinchicite|correct|chemspider}}
| StdInChIKey        = PWWVAXIEGOYWEE-UHFFFAOYSA-N
}}
<!-- Definition and medical uses -->

'''Promethazine''', sold under the brand name '''Phenergan''' among others, is a [[first-generation antihistamine]], [[sedative]], and [[antiemetic]] used to treat [[allergies]], [[insomnia]], and [[nausea]]. It may also help with some symptoms associated with the [[common cold]]<ref name=AHFS2018>{{cite web |title=Promethazine Hydrochloride Monograph for Professionals |url=https://www.drugs.com/monograph/promethazine-hydrochloride.html |website=Drugs.com |publisher=American Society of Health-System Pharmacists |access-date=24 October 2018}}</ref> and may also be used for [[sedating]] people who are agitated or anxious, an effect that has led to some [[recreational drug use|recreational use]] ([[lean (drug)|especially with codeine]]).<ref name="lean" /><ref name="BNF74" /><ref>{{cite book | vauthors = Malamed SF |title=Sedation: A Guide to Patient Management |date=2009 |publisher=Elsevier Health Sciences |isbn=978-0-323-07596-1 |page=113 |url=https://books.google.com/books?id=Abp9ci5-n1wC&pg=PA113 |language=en}}</ref> Promethazine is taken [[by mouth]] (oral), as a [[rectal suppository]], or by [[injection into a muscle]] (IM).<ref name=AHFS2018/>

<!-- Side effects and mechanism -->
Common side effects of promethazine include confusion and sleepiness;<ref name="AHFS2018" /> consumption of [[alcohol (drug)|alcohol]] or other sedatives can make these symptoms worse.<ref name=AHFS2018/> It is unclear if use of promethazine during [[pregnancy]] or [[breastfeeding]] is safe for the fetus.<ref name=AHFS2018/><ref name=BNF74>{{cite book|title=British national formulary: BNF 74|date=2017|publisher=British Medical Association|isbn=978-0-85711-298-9|page=276|edition=74}}</ref> Use of promethazine is not recommended in those less than two years old, due to potentially negative effects on breathing.<ref name=AHFS2018/> Use of promethazine by injection into a vein is not recommended, due to potential skin damage.<ref name=AHFS2018/> Promethazine is in the [[phenothiazine]] family of medications.<ref name=AHFS2018/> It is also a strong [[anticholinergic]], which produces its [[sedative]] effects. This also means high or toxic doses can act as a [[deliriant]].<ref>{{cite journal | vauthors = Page CB, Duffull SB, Whyte IM, Isbister GK | title = Promethazine overdose: clinical effects, predicting delirium and the effect of charcoal | journal = QJM | volume = 102 | issue = 2 | pages = 123–131 | date = February 2009 | pmid = 19042969 | doi = 10.1093/qjmed/hcn153 | s2cid = 17677540 | doi-access = free }}</ref>

<!-- History and culture -->
Promethazine was made in the 1940s by a team of scientists from [[Rhône-Poulenc]] laboratories.<ref>{{cite book | vauthors = Li JJ |title=Laughing Gas, Viagra, and Lipitor: The Human Stories behind the Drugs We Use |url=https://books.google.com/books?id=Z-4AQEqbE-MC&pg=PT146 |access-date=9 July 2016 |year=2006 |publisher=Oxford University Press |location=United Kingdom |isbn=978-0-19-988528-2 |page=146}}</ref> It was approved for medical use in the United States in 1951.<ref name=AHFS2018/> It is a [[generic medication]] and is available under many brand names globally.<ref name=brands>{{cite web|title=Promethazine international brands|url=https://www.drugs.com/international/promethazine.html|publisher=Drugs.com|access-date=17 July 2017}}</ref> In 2022, it was the 198th most commonly prescribed medication in the United States, with more than 2{{nbsp}}million prescriptions.<ref name="Top 300 of 2022">{{cite web | title=The Top 300 of 2022 | url=https://clincalc.com/DrugStats/Top300Drugs.aspx | website=ClinCalc | access-date=30 August 2024 | archive-date=30 August 2024 | archive-url=https://web.archive.org/web/20240830202410/https://clincalc.com/DrugStats/Top300Drugs.aspx | url-status=live }}</ref><ref>{{cite web | title = Promethazine Drug Usage Statistics, United States, 2013 - 2022 | website = ClinCalc | url = https://clincalc.com/DrugStats/Drugs/Promethazine | access-date = 30 August 2024 }}</ref> In 2022, the combination with [[dextromethorphan]] was the 260th most commonly prescribed medication in the United States, with more than 1{{nbsp}}million prescriptions.<ref name="Top 299 of 2022" /><ref>{{cite web | title = Dextromethorphan; Promethazine Drug Usage Statistics, United States, 2013 - 2022 | website = ClinCalc | url = https://clincalc.com/DrugStats/Drugs/DextromethorphanPromethazine | access-date = 30 August 2024 }}</ref>