DEXBROMPHENIRAMINE

Absorption

Antihistamines are well absorbed from the gastrointestinal tract after oral administration.

Toxicity

Signs of an overdose include fast or irregular heartbeat, mental or mood changes, tightness in the chest, and unusual tiredness or weakness.

Originator

Disomer,White,US,1959

The Uses of DEXBROMPHENIRAMINE

Antihistaminic.

Background

Dexbrompheniramine maleate is an antihistamine agent that is used for the treatment of allergic conditions, such as hay fever or urticaria.

Indications

For treatment and relief of symptoms of allergies, hay fever, and colds

Definition

ChEBI: The (pharmacologically active) (S)-(+)-enantiomer of brompheniramine. A histamine H1 receptor antagonist, it is used (commonly as its maleate salt) for the symptomatic relief of allergic conditions, including rhinitis nd conjunctivitis.

Manufacturing Process

The following is taken from US Patent 3,061,517. Sixteen grams of racemic 3- (2-pyridyl)-3-p-bromophenyl-N,N,-dimethylpropylamine and 9.7 grams of dphenylsuccinic acid are dissolved in 150 ml of absolute alcohol and kept at room temperature until crystallization is effected. The crystals are filtered,washed with absolute ethyl alcohol, and recrystallized from the same solvent using 5 ml there of per gram of solid. Three subsequent crystallizations from 80% alcohol give d-3-(2-pyridyl)-3-p-bromophenyl-N,N-dimethylpropylamined-phenylsuccinate; MP 152-154°C; [α]D25 91 (concentration, 1% in dimethylformamide).
The free base, d-3-(2-pyridyl)-3-p-bromophenyl-N,N-dimethylpropylamine, is obtained from this salt with diethyl ether and aqueous potassium carbonate; [α]D25 +42.7 (concentration, 1% in dimethylformamide). The free base is then reacted with maleic acid.

brand name

Disomer (Schering).

Therapeutic Function

Antihistaminic

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. Dexbrompheniramine is a histamine H1 antagonist (or more correctly, an inverse histamine agonist) of the alkylamine class. It provides effective, temporary relief of sneezing, watery and itchy eyes, and runny nose due to hay fever and other upper respiratory allergies.

Metabolism

Hepatic (cytochrome P-450 system), some renal.