HISTAGAN

Dexchlorpheniramine is the

S-enantiomer of chlorpheniramine which is a 1st generation anti-histamine.

Dexchlorpheniramine has more pharmacological activity than the R and so is more potent than the racemic mixture.

Dexchlorpheniramine can be used in the treatment of perennial and seasonal allergic rhinitis, vasomotor rhiniti, allergic conjunctivitis due to inhalant allergens and foods, mild uncomplicated allergic skin manifestations of urticaria and angioedema, amelioration of allergic reactions to blood or plasma, and dermographism.

In allergic reactions, an allergen binds to IgE antibodies on mast cells and basophils.

Once this occurs

IgE receptors crosslink with each other triggering a series of events that eventually leads to cell-degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil.

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.

Dexchlorpheniramine, is a histamine H1 antagonist of the alkylamine class.

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.

Hepatic metabolism.

Major metabolism by

CYP 2D6 and minor metabolism by 3A4, 2C11 and 2B1.

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Ask a doctor before use if you have ■ a cough that lasts or is chronic such as occurs with smoking, asthma, or emphysema ■ a cough that occurs with too much phlegm (mucus) ■ a breathing problem such as emphysema or chronic bronchitis ■ trouble urinating due to an enlarged prostate gland ■ glaucoma Ask a doctor or pharmacist before use if you are taking sedatives or tranquilizers When using this product ■ excitability may occur, especially in children ■ may cause marked drowsiness ■ alcohol, sedatives, and tranquilizers may increase the drowsiness effect ■ avoid alcoholic drinks ■ use caution when driving a motor vehicle or operating machinery Stop use and ask a doctor if ■ cough persists for more than 1 week, tends to recur, or is accompanied by a fever, rash or persistent headache.

A persistent cough may be a sign of a serious condition. ■ new symptoms occur If pregnant or breast-feeding, ask a health professional before use.

Keep out of reach of children.

In case of overdose, get medical help or contact a Poison Control Center right away.

Directions do not exceed recommended dosage. adults and children 12 years of age and over: 2 teaspoonfuls (10 mL) every 6 hours, not to exceed 8 teaspoonfuls (40 mL) in 24 hours. children to under 12 years of age: 1 teaspoonful (5 mL) every 6 hours, not to exceed 4 teaspoonfuls (20 mL) in 24 hours. children under 6 years of age: consult a doctor.

Other information ■ this packaging is child-resistant. ■ store at room temperature of 68°-86°F (20°-30°C) with excursions of 59°-86°F (15°-30°C).