QuickView for Clemastine (compound)

Summary
General Info

PubChem

PubChem Compound 26987

Name:	Clemastine
PubChem Compound ID:	26987
Description:	A histamine H1 antagonist used as the hydrogen fumarate in hay fever, rhinitis, allergic skin conditions, and pruritus. It causes drowsiness.
Molecular formula:	C₂₁H₂₆ClNO
Molecular weight:	343.89 g/mol
Synonyms:	14976-57-9; HS 592; 2(R)-[2-[(1R)-(4-Chlorophenyl)-1-phenyl-ethoxy]ethyl-1-methylpyrrolidine; SPBio_000817; Pyrrolidine, 2-(2-(1-(4-chlorophenyl)-1-phenylethoxy)ethyl)-1-methyl-, (R-(R,R))-; DivK1c_000285; Clemastine; Clemastine [USAN:BAN]; Clemastine (USAN); Mecloprodin. show more » 14976-57-9; HS 592; 2(R)-[2-[(1R)-(4-Chlorophenyl)-1-phenyl-ethoxy]ethyl-1-methylpyrrolidine; SPBio_000817; Pyrrolidine, 2-(2-(1-(4-chlorophenyl)-1-phenylethoxy)ethyl)-1-methyl-, (R-(R,R))-; DivK1c_000285; Clemastine; Clemastine [USAN:BAN]; Clemastine (USAN); Mecloprodin; HS-592; (+)-(2R)-2-(2-(((R)-p-Chloro-alpha-methyl-alpha-phenylbenzyl)oxy)ethyl)-1-methylpyrrolidine; NCGC00025168-01; AIDS-001634; KBio3_001265; Spectrum4_000955; Tavist (Fumarate); Prestwick1_000306; Prestwick0_000306; Lopac-C-8903; C06913; Clemastina [INN-Spanish]; NINDS_000285; SPBio_002491; Tocris-1453; 15686-51-8; Meclastin; Spectrum2_000689; 2-(2-(4-Chlor-alpha-methylbenzhydryloxy)ethyl)-1-methylpyrrolidin; KBio1_000285; KBioGR_001570; Clemastinum [INN-Latin]; Spectrum3_000353; D03535; NCGC00016710-01; CAS-14976-57-9; AIDS001634; NCGC00015281-01 show less «

DrugBank

Identification

Name:	Clemastine
Name (isomeric):	DB00283
Drug Type:	small molecule
Description:	A histamine H1 antagonist used as the hydrogen fumarate in hay fever, rhinitis, allergic skin conditions, and pruritus. It causes drowsiness.
Synonyms:	Clemastinum [INN-Latin]; Clemastine Fumarate; Clemastina [INN-Spanish]
Brand:	Meclastin, Mecloprodin, Tavist, Tavist-1
Brand name mixture:	Tavist-D Tablets(Clemastine + Phenylpropanolamine Hydrochloride)
Category:	Histamine H1 Antagonists, Antipruritics, Anti-Allergic Agents
CAS number:	15686-51-8

Pharmacology

Indication:	For the relief of symptoms associated with allergic rhinitis such as sneezing, rhinorrhea, pruritus and acrimation. Also for the management of mild, uncomplicated allergic skin manifestations of urticaria and angioedema. Used as self-medication for temporary relief of symptoms associated with the common cold.
Pharmacology:	Clemastine is an antihistamine with anticholinergic (drying) and sedative side effects. Antihistamines competitively antagonize various physiological effects of histamine including increased capillary permeability and dilatation, the formation of edema, the "flare" and "itch" response, and gastrointestinal and respiratory smooth muscle constriction... show more » Clemastine is an antihistamine with anticholinergic (drying) and sedative side effects. Antihistamines competitively antagonize various physiological effects of histamine including increased capillary permeability and dilatation, the formation of edema, the "flare" and "itch" response, and gastrointestinal and respiratory smooth muscle constriction. Within the vascular tree, H1- receptor antagonists inhibit both the vasoconstrictor and vasodilator effects of histamine. Depending on the dose, H1- receptor antagonists can produce CNS stimulation or depression. Most antihistamines exhibit central and/or peripheral anticholinergic activity. Antihistamines act by competitively blocking H1- receptor sites. Antihistamines do not pharmacologically antagonize or chemically inactivate histamine, nor do they prevent the release of histamine. show less «
Mechanism of Action:	Clemastine is a selective histamine H1 antagonist and binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.
Absorption:	Rapidly absorbed from the gastrointestinal tract.
Biotransformation:	Antihistamines appear to be metabolized in the liver chiefly via mono- and didemethylation and glucuronide conjugation.
Route of elimination:	Urinary excretion is the major mode of elimination.
Toxicity:	Oral LD₅₀ in rat and mouse is 3550 mg/kg and 730 mg/kg, respectively. Antihistamine overdosage reactions may vary from central nervous system depression to stimulation. In children, stimulation predominates initially in a syndrome which may include excitement, hallucinations, ataxia, incoordination, muscle twitching, athetosis, hyperthermia, cyanosis convulsions, tremors, and hyperreflexia followed by postictal depression and cardio-respiratory arrest. Convulsions in children may be preceded by mild depression. Dry mouth, fixed dilated pupils, flushing of the face, and fever are common. In adults, CNS depression, ranging from drowsiness to coma, is more common.
Affected organisms:	Humans and other mammals

Interactions

Food interaction:

Avoid alcohol.

Take with food.

Drug interaction:

Tacrine	The therapeutic effects of the central acetylcholinesterase inhibitor, Tacrine, and/or the anticholinergic, Clemastine, may be reduced due to antagonism. The interaction may be beneficial when the anticholinergic action is a side effect. Monitor for decreased efficacy of both agents.
Donepezil	Possible antagonism of action
Triprolidine	Concomitant therapy with triprolidine and clemastine, two anticholinergics and CNS depressants, may result in additive adverse/toxic effects. Monitor for enhanced anticholinergic and CNS depressant effects during concomitant therapy.
Trospium	Trospium and Clemastine, two anticholinergics, may cause additive anticholinergic effects and enhanced adverse/toxic effects. Monitor for enhanced anticholinergic effects.
Rivastigmine	Possible antagonism of action

Targets

Histamine H1 receptor

In peripheral tissues, the H1 subclass of histamine receptors mediates the contraction of smooth muscles, increase in capillary permeability due to contraction of terminal venules, and catecholamine release from adrenal medulla, as well as mediating neurotransmission in the central nervous system

UniProt ID:

P35367

Gene:

HRH1

Actions:

antagonist

References:

Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5.
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Taniguchi K, Urakami M, Takanaka K: [Effects of antiallergic agents on polymorphonuclear leukocytes. The inhibition of arachidonic acid release and superoxide production] Nippon Yakurigaku Zasshi. 1987 Aug;90(2):97-103.
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Hallberg T, Dohlsten M, Baldetorp B: Demonstration of histamine receptors on human platelets by flow cytometry. Scand J Haematol. 1984 Feb;32(2):113-8.
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Dorsch W, Hintschich C, Neuhauser J, Weber J: Sequential histamine inhalations cause increased bronchial histamine reactivity in guinea pigs: role of platelets, thromboxanes and prostacyclin. Naunyn Schmiedebergs Arch Pharmacol. 1984 Sep;327(2):148-55.
View Article

Taniguchi K, Masuda Y, Takanaka K: Inhibitory effects of histamine H1 receptor blocking drugs on metabolic activations of neutrophils. J Pharmacobiodyn. 1991 Feb;14(2):87-93.
View Article

Oishi R, Shishido S, Yamori M, Saeki K: Comparison of the effects of eleven histamine H1-receptor antagonists on monoamine turnover in the mouse brain. Naunyn Schmiedebergs Arch Pharmacol. 1994 Feb;349(2):140-4.
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Thomas RH, Browne PD, Kirby JD: The influence of ranitidine, alone and in combination with clemastine, on histamine-mediated cutaneous weal and flare reactions in human skin. Br J Clin Pharmacol. 1985 Oct;20(4):377-82.
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Thomson NC, Kerr JW: Effect of inhaled H1 and H2 receptor antagonist in normal and asthmatic subjects. Thorax. 1980 Jun;35(6):428-34.
View Article

Hayashi H, Okajima M, Yamada K: Atrial T (Ta) loop in dogs with or without atrial injury. Am Heart J. 1976 May;91(5):607-17.
View Article

Schran HF, Petryk L, Chang CT, O'Connor R, Gelbert MB: The pharmacokinetics and bioavailability of clemastine and phenylpropanolamine in single-component and combination formulations. J Clin Pharmacol. 1996 Oct;36(10):911-22.
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Enzymes

Cytochrome P450 2D6

Cytochrome P450 3A4