ICD-10 Specific code L50: Urticaria

Bilastine is a non-sedating, long-acting histamine antagonist with selective peripheral Η₁ receptor antagonist affinity and no affinity for muscarinic receptors.

Chlorphenamine is a potent antihistamine (H₁-antagonist). Antihistamines diminish or abolish the actions of histamine in the body by competitive reversible blockade of histamine H₁-receptor sites on tissues. Chlorphenamine also has anticholinergic activity.

Cyproheptadine is a first generation antihistamine which also has anticholinergic and antiserotonergic activities that is used to treat allergic conditions including seasonal rhinitis, conjunctivitis, dermatitits and urticaria.

Desloratadine is a non-sedating, long-acting histamine antagonist with selective peripheral H₁-receptor antagonist activity. After oral administration, desloratadine selectively blocks peripheral histamine Η₁-receptors because the substance is excluded from entry to the central nervous system.

Dexchlorpheniramine, the d-isomer of the racemic compound chlorpheniramine, is two times more active than chlorpheniramine. Dexchlorpheniramine does not prevent the release of histamine, but rather, competes with free histamine for binding at the H₁-receptor sites, and competitively antagonizes the effects of histamine on H₁-receptors in the GI tract, uterus, large blood vessels, and bronchial muscle. Blockade of H₁-receptors also suppresses the formation of oedema, flare, and pruritus that result from histaminic activity. Since dexchlorpheniramine binds to central and peripheral H₁-receptors, sedative effects are likely to occur. Dexchlorpheniramine has high antihistaminic activity, moderate anticholinergic effects and minimal sedative effects.

Dimetindene is an antihistaminic of the alkylamine group. Its action is the result of the capture of histamine Η₁ subunits. It has mild anticholinergic and sedative action.

The triamterene and hydrochlorothiazide combination is a diuretic/antihypertensive drug product that combines natriuretic and antikaliuretic effects. Each component complements the action of the other.

Levocetirizine, the ® enantiomer of cetirizine, is a potent and selective antagonist of peripheral H₁-receptors. Pharmacodynamic studies in healthy volunteers demonstrate that, at half the dose, levocetirizine has comparable activity to cetirizine, both in the skin and in the nose.

Mequitazine is a phenothiazine derivative with the actions and uses of antihistamines. Antihistamines diminish or abolish the main actions of histamine in the body by competitive, reversible blaockade of histamine receptor site on tissues; they do not inactivate histamine or prevent its synthesis or release. Antihistamines are used for palliative treatment of allergic reactions.

Promethazine is a potent, long acting, antihistamine with additional anti-emetic central sedative and anti-cholinergic properties.

Rupatadine is a second-generation antihistamine, long-acting histamine antagonist, with selective peripheral H1-receptor antagonist activity. Some of the metabolites (desloratadine and its hydroxylated metabolites) retain an antihistaminic activity and may partially contribute to the overall efficacy of the drug.