Drugs Acting On The Upper Respiratory System PDF

DRUGS ACTING ON THE UPPER RESPIRATORY SYSTEM ANTITUSSIVES Many disorders of the respiratory tract are accompanied by unproductive cough, including: Common cold Sinusitis pharyngitis Loading… Pneumonia  Antitussive drugs Common example...

DRUGS ACTING ON THE UPPER RESPIRATORY SYSTEM ANTITUSSIVES Many disorders of the respiratory tract are accompanied by unproductive cough, including: Common cold Sinusitis pharyngitis Loading… Pneumonia  Antitussive drugs Common examples: codeine and dextromethorphan Mechanism of action: act directly on the medullary cough center of the brain to depress the cough reflex. Indications: Treatment of nonproductive cough (dry cough) Adverse Effects of Codiene Constipation Dysphoria: restlessness Fatigue Loading… Addictive potential  DECONGESTANTS Mechansim of action: alpha-1 agonsits that cause local vasoconstriction. Decrease edema and inflammation of the nasal membranes. Cause shrinking of swollen mucous membranes and open clogged nasal passages, Decrease the overproduction of secretions by to the upper respiratory tract. Topical Nasal Decongestants Common examples: Oxymetazoline, Phenylephrine Indications Relieves discomfort of nasal congestion associated with the common cold, sinusitis, allergic rhinitis Relieves pressure of otitis media Oral Decongestants Refer to pseudoephedrine in previous chapters  Topical Nasal Steroids Example: Budesonide Applied by a nasal spray Therapeutic Actions Produce local antiinflammatory effects Indications Used as a prophylaxis against seasonal allergic rhinitis Adverse Effects of nasal steroids Local burning, irritation, stinging, dryness of the mucosa, ANTIHISTAMINES Note: histamine is a chemical released during inflammation that increases secretions and narrows airways. Mechansim of action of antihistamines: They Block the histamine type-1 receptors, Loading… thus prevent the development of the inflammatory effects of histamine  antihistamines consist two generations First-generation (Chlorpheniramine, Diphenhydramine): produce significant sedation and anticholinergic side effects Second-generation (Loratidine, Fexofenadine), less-sedating (preferred). Clinical indications for antihistamines Relief of symptoms associated with seasonal and perennial allergic rhinitis allergic conjunctivitis uncomplicated urticarial angioedema Adjunctive therapy in anaphylactic reactions and drug allergy Adjunctive therapy in asthma and bronchoconstriction Relief of nausea and vomiting associated with motion sickness Adjunctive therapy in inducing sedation  Adverse Effects of ANTIHISTAMINES Drowsiness and sedation (not by second-generation). The anticholinergic effects: Dry mouth Constipation Arrhythmias Urinary retension EXPECTORANTS: Guaifenesin Therapeutic Actions Enhances the secretions of respiratory tract fluids Reduces the adhesiveness and surface tension of these fluids Allowing easier movement of the less viscous secretions. Results in a more productive cough and thus decreased frequency of coughing. Indications of the expectorants Symptomatic relief of respiratory conditions characterized by a dry, nonproductive cough, including the common cold, acute bronchitis, and influenza  MUCOLYTICS: Acetylcysteine Mechansim of action as a mucolytic Interact with and break the mucoproteins in the respiratory secretions The result is a decrease in the viscosity of the secretions. Acetylcysteine as an antidote Mechansim of action as an antidote for paracetamol toxicity It interacts with the toxic metabolite of paracetamol and protect liver cells from being damaged