Mequitazine

4.01e-03 g/L

>48.4 [ug/mL] (The mean of the results at pH 7.4)

Danger

H301 (66.7%): Toxic if swallowed [Danger Acute toxicity, oral]

P261, P264, P264+P265, P270, P271, P272, P273, P280, P301+P316, P301+P317, P302+P352, P304+P340, P305+P354+P338, P317, P321, P330, P332+P317, P333+P317, P362+P364, P391, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 6 reports by companies from 3 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Drug-Induced Liver Injury Severity and Toxicity (DILIst)

Mequitazine

DILI Positive

DOI:10.1016/j.drudis.2019.09.022

R - Respiratory system

QR - Respiratory system

In allergic reactions an allergen interacts with and cross-links surface IgE antibodies on mast cells and basophils. Once the mast cell-antibody-antigen complex is formed, a complex series of events occurs that eventually leads to cell-degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil. Once released, histamine can react with local or widespread tissues through histamine receptors. Histamine, acting on H₁-receptors, produces pruritis, vasodilatation, hypotension, flushing, headache, tachycardia, and bronchoconstriction. Histamine also increases vascular permeability and potentiates pain. Mequitazine is a histamine H1 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.

Mequitazine binds to the histamine H1 receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.

Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.