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Respiratory System PHARMACOLOGY. Dr Nasim Ullah Siddiqui. DRUGS USED TO TREAT ALLERGIC RHINITIS . Rhinitis is an inflammation of the mucous membranes of the nose and is characterized by sneezing, itchy nose/eyes, watery rhinorrhea, and nasal congestion.
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Respiratory System PHARMACOLOGY DrNasimUllahSiddiqui
DRUGS USED TO TREAT ALLERGIC RHINITIS • Rhinitis is an inflammation of the mucous membranes of the nose and is characterized by sneezing, itchy nose/eyes, watery rhinorrhea, and nasal congestion. • An attack may be precipitated by inhalation of an allergen (such as dust, pollen, or animal dander).
DRUGS USED TO TREAT ALLERGIC RHINITIS • The foreign material interacts with mast cells coated with IgE generated in response to a previous allergen exposure . • The mast cells release mediators, such as histamine, leukotrienes, and chemotactic factors, that promote bronchiolar spasm and mucosal thickening from edema and cellular infiltration.
DRUGS USED TO TREAT ALLERGIC RHINITIS • Combinations of oral antihistamines with decongestants are the first-line therapies for allergic rhinitis. • Systemic effects associated with these oral preparations (sedation, insomnia, and, rarely, cardiac arrhythmias) have prompted interest in topical intranasal delivery of drugs.
DRUGS USED TO TREAT ALLERGIC RHINITIS Antihistamines (H1-receptor blockers) • Antihistamines are the most frequently used agents in the treatment of sneezing and watery rhinorrhea associated with allergic rhinitis. • H1-histamine receptor blockers, such as diphenhydramine, chlorpheniramine , loratadine , and fexofenadine, are useful in treating the symptoms of allergic rhinitis caused by histamine release.
DRUGS USED TO TREAT ALLERGIC RHINITIS • Ocular and nasal antihistamine delivery devices are available over-the-counter for more targeted tissue delivery. • Combinations of antihistamines with decongestants are effective when congestion is a feature of rhinitis.
DRUGS USED TO TREAT ALLERGIC RHINITIS • Antihistamines differ in their ability to cause sedation and in their duration of action. • In general, anticholinergic side effects of the first-generation antihistamines (dry eyes/mouth, difficulty urinating and/or defecating) are transient and may resolve in 7 to 10 days.
DRUGS USED TO TREAT ALLERGIC RHINITIS α-Adrenergic agonists • Short-acting α-adrenergic agonists (“nasal decongestants”), such as phenylephrine, constrict dilated arterioles in the nasal mucosa and reduce airway resistance. • Longer-acting oxymetazolineadministered as an aerosol, these drugs have a rapid onset of action and show few systemic effects.
DRUGS USED TO TREAT ALLERGIC RHINITIS • Oral administration results in longer duration of action but also increased systemic effects. • Combinations of these agents with antihistamines are frequently used. • The α-adrenergic agonists should be used no longer than several days due to the risk of rebound nasal congestion. • α-Adrenergic agents have no place in the long-term treatment of allergic rhinitis.
DRUGS USED TO TREAT ALLERGIC RHINITIS Corticosteroids • Corticosteroids, such as beclomethasone & triamcinolone, are effective when administered as nasal sprays. • Topical steroids may be more effective than systemic antihistamines in relieving the nasal symptoms of both allergic and non allergic rhinitis. • Treatment of chronic rhinitis may not result in improvement until 1 to 2 weeks after starting therapy.
DRUGS USED TO TREAT ALLERGIC RHINITIS Cromolyn • Intranasal cromolyn may be useful, particularly when administered before contact with an allergen. • To optimize the therapeutic effect of cromolyn, dosing should occur at least 1 to 2 weeks prior to allergen exposure. • Due to a short duration of action, cromolyn requires multiple daily dosing.
REFRENCES LIPPINCOTTES PHARMACOLOGY THANK YOU