Methapyrilene

{{Short description|Chemical compound}}

{{hatnote|"Thionylan" redirects here. Not to be confused with thionyl halides: thionyl fluoride, thionyl chloride and thionyl bromide.}}

{{Drugbox

| Watchedfields = changed

| verifiedrevid = 447612304

| IUPAC_name = N,N-dimethyl-N'-pyridin-2-yl-N'-(2-thienylmethyl)ethane-1,2-diamine

| image = Methapyrilene.svg

| width = 155

| tradename =

| pregnancy_category =

| legal_status =

| routes_of_administration =

| bioavailability =

| protein_bound =

| metabolism =

| elimination_half-life =

| excretion =

| CAS_number_Ref = {{cascite|correct|??}}

| CAS_number = 91-80-5

| ATC_prefix = R06

| ATC_suffix = AC05

| PubChem = 4098

| DrugBank_Ref = {{drugbankcite|correct|drugbank}}

| DrugBank = DB04819

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 3956

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = A01LX40298

| KEGG_Ref = {{keggcite|correct|kegg}}

| KEGG = C11114

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 6820

| C=14 | H=19 | N=3 | S=1

| smiles = n1ccccc1N(CCN(C)C)Cc2sccc2

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C14H19N3S/c1-16(2)9-10-17(12-13-6-5-11-18-13)14-7-3-4-8-15-14/h3-8,11H,9-10,12H2,1-2H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = HNJJXZKZRAWDPF-UHFFFAOYSA-N

}}

Methapyrilene is an antihistamine and anticholinergic of the pyridine chemical class which was developed in the early 1950s. It was sold under the trade names Co-Pyronil and Histadyl EC in the UK.{{cite news |date=July 1979 |title=Archive. |url=http://www.thefreelibrary.com/Archive.-a0119048413 |work=Birmingham Post |via=The Free Library}} It has relatively strong sedative effects, to the extent that its primary use was as a medication for insomnia rather than for its antihistamine action. Together with scopolamine, it was the main ingredient in Sominex, Nytol, and Sleep-Eze. It also provided the sedative component of Excedrin PM.{{cite news |date=1978-06-13 |title=FDA Seeks Restrictions On Sleeping Aid Drugs |url=https://newspapers.com/image/233886246/ |url-access=subscription |work=Daily Press |via=Newspapers.com |volume=83 |issue=164 |page=1}} All of these products were reformulated in the late 1970s{{cite news | vauthors = Cook C |date=1979-06-28 |title=Sleep aids back with new drug {{!}} Critics assail 'human testing' |url=https://www.newspapers.com/image/191023340/ |url-access=subscription |work=The Minneapolis Star |via=Newspapers.com |pages=[https://www.newspapers.com/newspage/191023340/ 1A], [https://www.newspapers.com/newspage/191023631/ 6A]}} when methapyrilene was demonstrated to cause liver cancer in rats when given chronically.{{cite journal | vauthors = Lijinsky W, Reuber MD, Blackwell BN | title = Liver tumors induced in rats by oral administration of the antihistaminic methapyrilene hydrochloride | journal = Science | volume = 209 | issue = 4458 | pages = 817–819 | date = August 1980 | pmid = 7403848 | doi = 10.1126/science.7403848 | bibcode = 1980Sci...209..817L }}