Title: Acrivastine
CAS Registry Number: 87848-99-5
CAS Name: (2E)-3-[6-[(1E)-1-(4-Methylphenyl)-3-(1-pyrrolidinyl)-1-propenyl]-2-pyridinyl]-2-propenoic acid
Additional Names: (E)-6-[(E)-3-(1-pyrrolidinyl)-1-p-tolylpropenyl]-2-pyridineacrylic acid
Manufacturers' Codes: BW-270C; BW-825C; BW-A825C
Trademarks: Semprex (GSK)
Molecular Formula: C22H24N2O2
Molecular Weight: 348.44
Percent Composition: C 75.83%, H 6.94%, N 8.04%, O 9.18%
Literature References: Nonsedating type histamine H1-receptor antagonist; analog of triprolidine, q.v. Prepn: G. G. Coker, J. W. A. Findlay, EP 85959 (1983 to Wellcome); J. W. A. Findlay, G. G. Coker, US 4501893 (1985). Pharmacodynamics and pharmacokinetics in humans: A. F. Cohen et al., Eur. J. Clin. Pharmacol. 28, 197 (1985). Evaluation of CNS effects: A. F. Cohen et al., Clin. Pharmacol. Ther. 38, 381 (1985). Clinical trials in idiopathic urticaria: J. G. Gibson et al., Dermatologica 169, 179 (1984); H. Neittaanmaki et al., ibid. 177, 98 (1988); in allergic rhinitis: T. G. Gibbs et al., J. Int. Med. Res. 16, 413 (1988). Review of pharmacology and therapeutic efficacy: R. N. Brogden, D. McTavish, Drugs 41, 927-940 (1991).
Properties: Crystals from isopropanol, mp 222° (dec).
Melting point: mp 222° (dec)
NOTE: Combination with pseudoephedrine, Duact (Glaxo Wellcome) .
Therap-Cat: Antihistaminic.
Keywords: Antihistaminic; Alkylamine Derivatives.
Acrolein Acrylamide Acrylic Acid Acrylonitrile Actaplanins

Systematic (IUPAC) name
prop-1-enyl]pyridin-2-yl}prop-2-enoic acid
Clinical data
AHFS/ International Drug Names
MedlinePlus a682619
Pregnancy cat. B (US)
Legal status -only (US)
Routes oral
Pharmacokinetic data
Half-life 1.5 hours
Excretion Renal
CAS number 87848-99-5 N
ATC code R06AX18
PubChem CID 5284514
ChemSpider 4447574 YesY
KEGG D02760 YesY
Chemical data
Formula C22H24N2O2 
Mol. mass 348.438 g/mol
 N (what is this?)  (verify)

Acrivastine is a medication used for the treatment of allergies and hay fever. It is a second-generation H1-receptor antagonist antihistamine (like its base molecule triprolidine) and works by blocking Histamine H1 receptors.

This non-sedating antihistamine is sold under the brand name Benadryl Allergy Relief in the United Kingdom by McNeil Laboratories, not to be confused with Benadryl Once a Day, which is cetirizine and is also sold by McNeil in the UK. It is available as an over-the-counter medication in the UK.

In the U.S., acrivastine is the active ingredient in the Semprex brand. Semprex-D is also acrivastine-based, but contains a decongestant, pseudoephedrine. Semprex-D is marketed in the U.S. by Actient Pharmaceuticals.[1]