METHDILAZINE (200 MG)

Absorption

Well absorbed in the digestive tract.

Toxicity

Symptoms of overdose include clumsiness or unsteadiness, convulsions, drowsiness, dryness of mouth, nose, or throat, feeling faint, flushing or redness of face, hallucinations, muscle spasms (especially of neck and back), restlessness, shortness of breath or troubled breathing, shuffling walk, tic-like movements of head and face, trembling and shaking of hands, and trouble in sleeping.

Originator

Tacaryl ,Westwood,US,1960

The Uses of METHDILAZINE (200 MG)

Antipruritic.

Background

Methdilazine is a phenothiazine compound with antihistaminic activity. It is used in the treatment of various dermatoses to relieve pruritus.

Indications

Used for the symptomatic relief of hypersensitivity reactions and particularly for the control of pruritic skin disorders

Definition

ChEBI: Methdilazine is a phenothiazine substituted on nitrogen by a (1-methylpyrrolidin-3-yl)methyl group; a first-generation antihistamine with anticholinergic properties. It has a role as a histamine antagonist, a cholinergic antagonist and an antipruritic drug. It is a member of phenothiazines and a N-alkylpyrrolidine.

Manufacturing Process

10.8 parts of 10-(1-methyl-3-pyrrolidylmethyl) phenothiazine (prepared from 1-methyl-3-pyrrolidylmethyl chloride by reaction with phenothiazine) in 80 parts of 99% isopropyl alcohol were treated with a solution of 1.33 parts of hydrogen chloride in 30 parts of the same solvent. The clear light yellow solution soon deposited white crystals of the acid addition salt. After cooling overnight at 0°C, the crystalline product was collected on a filter, washed with 99% isopropyl alcohol and anhydrous ether and then dried in a vacuum oven at 95°C. Yield 10.4 parts, MP 187.5° to 189°C.

brand name

Tacaryl (Westwood-Squibb).

Therapeutic Function

Antipruritic

General Description

Crystals.

General Description

Methdilazine, 10-[(1-methyl-3-pyrrolidinyl)methyl]phenothiazine (Tacaryl), is a light-tan crystallinepowder that has a characteristic odor and is practicallyinsoluble in water. Methdilazine, as the free base, isused in chewable tablets because its low solubility in watercontributes to its tastelessness. Some local anesthesia of thebuccal mucosa may be experienced if the tablet is chewedand not swallowed promptly.

Reactivity Profile

METHDILAZINE (200 MG) is sensitive to light. .

Health Hazard

SYMPTOMS: Symptoms of exposure to METHDILAZINE (200 MG) may include drowsiness, hypotension, tachycardia, dryness of the mouth, nausea, nasal congestion, fever and tremors.

Fire Hazard

Flash point data for METHDILAZINE (200 MG) are not available. METHDILAZINE (200 MG) is probably combustible.

Pharmacokinetics

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. Methdilazine 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.

Metabolism

Not Available