MEQUITAZINE

Details

Stereochemistry	RACEMIC
Molecular Formula	C20H22N2S
Molecular Weight	322.467
Optical Activity	( + / - )
Defined Stereocenters	0 / 1
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

C(C1CN2CCC1CC2)N3C4=CC=CC=C4SC5=CC=CC=C35

InChI

InChIKey=HOKDBMAJZXIPGC-UHFFFAOYSA-N

InChI=1S/C20H22N2S/c1-3-7-19-17(5-1)22(18-6-2-4-8-20(18)23-19)14-16-13-21-11-9-15(16)10-12-21/h1-8,15-16H,9-14H2

HIDE SMILES / InChI

Molecular Formula	C20H22N2S
Molecular Weight	322.467
Charge	0
Count

Stereochemistry	RACEMIC
Additional Stereochemistry	No
Defined Stereocenters	0 / 1
E/Z Centers	0
Optical Activity	( + / - )

Description
Sources: http://www.mhra.gov.uk/home/groups/par/documents/websiteresources/con126029.pdf
Curator's Comment: description was created based on several sources, including https://www.drugbank.ca/drugs/DB01071

Mequitazine (PRIMALAN®) is a phenothiazine derivative and a histamine H1-receptor antagonist. It competes with histamine for the normal H1-receptor sites on effector cells of the gastrointestinal tract, blood vessels and respiratory tract. It provides effective, temporary relief of sneezing, watery and itchy eyes, and runny nose due to hay fever and other upper respiratory allergies.

CNS Activity

Originator

Approval Year

Targets

Primary Target	Pharmacology	Condition	Potency
Histamine H1 receptor 316 Target ID: CHEMBL3943 Sources: https://www.drugbank.ca/drugs/DB01071	Antagonist 2849		280.0 nM [Ki]

Conditions

Condition	Modality	Highest Phase	Product
Allergic rhinitis 104 Sources: http://www.mhra.gov.uk/home/groups/par/documents/websiteresources/con126029.pdf	Primary	Approved 8583	PRIMALAN Approved Use Antihistamine for the treatment of allergic conditions such as hay fever, perennial rhinitis, urticaria, pruritis of allergic origin and allergic reactions associated with insect bites and stings. Launch Date 1984
Perennial allergic rhinitis 47 Sources: http://www.mhra.gov.uk/home/groups/par/documents/websiteresources/con126029.pdf	Primary	Approved 8583	PRIMALAN Approved Use Antihistamine for the treatment of allergic conditions such as hay fever, perennial rhinitis, urticaria, pruritis of allergic origin and allergic reactions associated with insect bites and stings. Launch Date 1984
Urticaria 39 Sources: http://www.mhra.gov.uk/home/groups/par/documents/websiteresources/con126029.pdf	Primary	Approved 8583	PRIMALAN Approved Use Antihistamine for the treatment of allergic conditions such as hay fever, perennial rhinitis, urticaria, pruritis of allergic origin and allergic reactions associated with insect bites and stings. Launch Date 1984
Pruritus 31 Sources: http://www.mhra.gov.uk/home/groups/par/documents/websiteresources/con126029.pdf	Primary	Approved 8583	PRIMALAN Approved Use Antihistamine for the treatment of allergic conditions such as hay fever, perennial rhinitis, urticaria, pruritis of allergic origin and allergic reactions associated with insect bites and stings. Launch Date 1984

PubMed

Title	Date	PubMed
[Efficacy of mequitazine (Primalan) on the relief of symptoms of allergic rhinoconjunctivitis in children. Documented clinical experience].	2006-03-30	16568706
Inhibitory effects of nicardipine to cytochrome P450 (CYP) in human liver microsomes.	2005-05	15863898
A dose-ranging study of the effects of mequitazine on actual driving, memory and psychomotor performance as compared to dexchlorpheniramine, cetirizine and placebo.	2004-02	14987305
Ketoconazole potentiates terfenadine-induced apoptosis in human Hep G2 cells through inhibition of cytochrome p450 3A4 activity.	2002	12244568
Oxidation of histamine H1 antagonist mequitazine is catalyzed by cytochrome P450 2D6 in human liver microsomes.	1998-02	9454781
Efficacy of mequitazine in comparison with placebo assessed by ocular challenge with allergen in allergic conjunctivitis.	1997-04	9188930
The histamine H1-receptor antagonist binding site. A stereoselective pharmacophoric model based upon (semi-)rigid H1-antagonists and including a known interaction site on the receptor.	1995-08-18	7650688
In vivo and in vitro interaction of the novel selective histamine H1 receptor antagonist mizolastine with H1 receptors in the rodent.	1995-05	7612054
"In vivo" and "in vitro" evaluation of four antihistamines (astemizole, azatadine, mequitazine, terfenadine).	1989-03-01	2476015
[Comparative study of a new antihistamine, mequitazine, and placebos].	1975-11	1959

Patents

Sample Use Guides

In Vivo Use Guide

The usual dose for adults is one 5 mg tablet to be taken orally twice a day, although in elderly patients (over 65 years) caution should be used.

Route of Administration: Oral

In Vitro Use Guide

The affinity of mequitazine for H1 receptors in guinea pigs was compared with that of classical sedative antihistamines ((+)-chlorpheniramine and promethazine). In vitro determinations of Ki values of [3H]mepyramine binding in the brain reveal that mequitazine is 15 to 20 times less potent than (+)-chlorpheniramine and promethazine (Ki value was 280 nM, 12 nM and 17 nM, respectively).

Substance Class	Chemical Created by `admin` on `Mon Mar 31 17:55:29 GMT 2025` Edited by `admin` on `Mon Mar 31 17:55:29 GMT 2025`
Record UNII	Y463242LY2
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

MEQUITAZINE

Official Name

English

KITAZEMIN

Preferred Name

English

MEQUITAZINE [MI]

Common Name

English

MEQUITAZINE [JAN]

Common Name

English

Mequitazine [WHO-DD]

Common Name

English

NSC-303612

Code

English

MEQUITAZINE [MART.]

Common Name

English

mequitazine [INN]

Common Name

English

10-(3-QUINUCLIDINYLMETHYL)PHENOTHIAZINE

Systematic Name

English

Classification Tree Code System Code

WHO-VATC

QR06AD07