Chlorpheniramine¿¡ ´ëÇÑ Mechanism_Of_Action Á¤º¸ Chlorpheniramine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Guaifenesin¿¡ ´ëÇÑ Mechanism_Of_Action Á¤º¸ Guaifenesin may act as an irritant to gastric vagal receptors, and recruit efferent parasympathetic reflexes that cause glandular exocytosis of a less viscous mucus mixture. Cough may be provoked. This combination may flush tenacious, congealed mucopurulent material from obstructed small airways and lead to a temporary improvement in dyspnea or the work of breathing.
Pharmacology
Chlorpheniramine¿¡ ´ëÇÑ Pharmacology Á¤º¸ 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. Chlorpheniramine, is a histamine H1 antagonist (or more correctly, an inverse histamine agonist) 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. Guaifenesin¿¡ ´ëÇÑ Pharmacology Á¤º¸ Guaifenesin is an expectorant which increases the output of phlegm (sputum) and bronchial secretions by reducing adhesiveness and surface tension. The increased flow of less viscous secretions promotes ciliary action and changes a dry, unproductive cough to one that is more productive and less frequent. By reducing the viscosity and adhesiveness of secretions, guaifenesin increases the efficacy of the mucociliary mechanism in removing accumulated secretions from the upper and lower airway.
Chlorpheniramine¿¡ ´ëÇÑ Absorption Á¤º¸ Well absorbed in the gastrointestinal tract. Guaifenesin¿¡ ´ëÇÑ Absorption Á¤º¸ Rapidly absorbed from the GI tract
Chlorpheniramine¿¡ ´ëÇÑ Biotransformation Á¤º¸ Primarily hepatic via Cytochrome P450 (CYP450) enzymes. Guaifenesin¿¡ ´ëÇÑ Biotransformation Á¤º¸ Rapidly hydrolyzed (60% within seven hours) and then excreted in the urine, with beta-(2-methoxyphenoxy)-lactic acid as its major urinary metabolite.
Toxicity
Chlorpheniramine¿¡ ´ëÇÑ Toxicity Á¤º¸ LD50 = 306 mg/kg in humans, mild reproductive toxin to women of childbearing age. Guaifenesin¿¡ ´ëÇÑ Toxicity Á¤º¸ LD50 1510 mg/kg (rat, oral)
Drug Interactions
Chlorpheniramine¿¡ ´ëÇÑ Drug_Interactions Á¤º¸ Donepezil Possible antagonism of actionGalantamine Possible antagonism of actionRivastigmine Possible antagonism of actionEthotoin The antihistamine increases the effect of hydantoinFosphenytoin The antihistamine increases the effect of hydantoinMephenytoin The antihistamine increases the effect of hydantoinPhenytoin The antihistamine increases the effect of hydantoin Guaifenesin¿¡ ´ëÇÑ Drug_Interactions Á¤º¸ Not Available
Chlorpheniramine¿¡ ´ëÇÑ Food Interaction Á¤º¸ Take with food.Avoid alcohol. Guaifenesin¿¡ ´ëÇÑ Food Interaction Á¤º¸ Take with a full glass of water.Take without regard to meals.
Chlorpheniramine¿¡ ´ëÇÑ Description Á¤º¸ A histamine H1 antagonist used in allergic reactions, hay fever, rhinitis, urticaria, and asthma. It has also been used in veterinary applications. One of the most widely used of the classical antihistaminics, it generally causes less drowsiness and sedation than promethazine. [PubChem] Guaifenesin¿¡ ´ëÇÑ Description Á¤º¸ An expectorant that also has some muscle relaxing action. It is used in many cough preparations. [PubChem]