Clemastine

Clemastine
Clinical data
AHFS/Drugs.com	Monograph
MedlinePlus	a682542
Routes of; administration	Oral
ATC code	D04AA14 (WHO) R06AA04 (WHO);
Legal status
Legal status	In general: Over-the-counter (OTC);
Pharmacokinetic data
Bioavailability	39.2%
Metabolism	Hepatic
Elimination half-life	21.3 hours
Excretion	Renal
Identifiers
	IUPAC name (2R)-2-{2-[(1R)-1-(4-chlorophenyl)-1-phenylethoxy]ethyl}-1-methylpyrrolidine;
CAS Number	15686-51-8 ;
PubChem CID	26987;
IUPHAR/BPS	6063;
DrugBank	DB00283 ;
ChemSpider	25129 ;
UNII	95QN29S1ID;
KEGG	D03535 ;
ChEBI	CHEBI:3738 ;
ChEMBL	ChEMBL1626 ;
CompTox Dashboard (EPA)	DTXSID2022832 ;
Chemical and physical data
Formula	C21H26ClNO
Molar mass	343.90 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES Clc1ccc(cc1)[C@](OCC[C@@H]2N(C)CCC2)(c3ccccc3)C;
	InChI InChI=1S/C21H26ClNO/c1-21(17-7-4-3-5-8-17,18-10-12-19(22)13-11-18)24-16-14-20-9-6-15-23(20)2/h3-5,7-8,10-13,20H,6,9,14-16H2,1-2H3/t20-,21-/m1/s1 ; Key:YNNUSGIPVFPVBX-NHCUHLMSSA-N ;
	(verify)

Clemastine, also known as meclastin, is a first-generation H1 histamine antagonist (antihistamine) with anticholinergic properties (drying) and sedative side effects. Like all first-generation antihistamines, it is sedating.

Patented in 1960, it came into medical use in 1967.