Chemistry:Mepyramine

Short description: First generation antihistamine

Mepyramine

Clinical data
Other names	Pyrilamine; N-[2-(dimethylamino)ethyl]-N-[(4-methoxyphenyl)methyl]pyridin-2-amine
AHFS/Drugs.com	International Drug Names
MedlinePlus	a606008
Routes of administration	oral, topical,
ATC code	R06AC01 (WHO) D04AA02 (WHO)
Legal status
Legal status	In general: Over-the-counter (OTC)
Identifiers
IUPAC name N-(4-methoxybenzyl)-N',N'-dimethyl-N-pyridin-2-ylethane-1,2-diamine
CAS Number	91-84-9 Y 59-33-6 (maleate)
PubChem CID	4992
IUPHAR/BPS	1227
DrugBank	DB06691 N
ChemSpider	4818 Y
UNII	HPE317O9TL
KEGG	D08183 Y
ChEBI	CHEBI:6762 N
ChEMBL	ChEMBL511 Y
Chemical and physical data
Formula	C17H23N3O
Molar mass	285.391 g·mol−1
3D model (JSmol)	Interactive image
SMILES O(c1ccc(cc1)CN(c2ncccc2)CCN(C)C)C
InChI InChI=1S/C17H23N3O/c1-19(2)12-13-20(17-6-4-5-11-18-17)14-15-7-9-16(21-3)10-8-15/h4-11H,12-14H2,1-3H3 Y Key:YECBIJXISLIIDS-UHFFFAOYSA-N Y
NY (what is this?)  (verify)

Mepyramine, also known as pyrilamine, is a first generation antihistamine, targeting the H₁ receptor as an inverse agonist. Mepyramine rapidly permeates the brain, often causing drowsiness. It is often sold as a maleate salt, pyrilamine maleate.

The medication has negligible anticholinergic activity, with 130,000-fold selectivity for the histamine H₁ receptor over the muscarinic acetylcholine receptors (for comparison, diphenhydramine had 20-fold selectivity for the H₁ receptor).

It was patented in 1943 and came into medical use in 1949. It was marketed under the names Histadyl, Histalon, Neo-Antergan, Neo-Pyramine, and Nisaval. In the 1960s and 70s it was a very common component in over-the-counter sleep aids such as "Alva-Tranquil", "Dormin", "Sedacaps", "Sominex", "Nytol", and many others.

It is used in over-the-counter combination products to treat the common cold and menstrual symptoms such as Midol Complete. It is also the active ingredient of the topical antihistamine creams Anthisan and Neoantergan sold for the treatment of insect bites, stings, and nettle rash.

See also

• Chloropyramine (chloro instead of methoxy)