Upper Respiratory Tract Pharmacology (PDF)

# 371120-2 Pharmacology for Nursing ## Unit II: The Pharmacology of Physiological Systems ### **Chapter 9: Drugs Acting on the Respiratory Tract** **Dr. Hanan A. M. Youssef** RN, MNS, DNS Associate Professor- Emergency & Critical Care Nursing Nursing Department – Taif University ## Drugs Acti...

# 371120-2 Pharmacology for Nursing ## Unit II: The Pharmacology of Physiological Systems ### **Chapter 9: Drugs Acting on the Respiratory Tract** **Dr. Hanan A. M. Youssef** RN, MNS, DNS Associate Professor- Emergency & Critical Care Nursing Nursing Department – Taif University ## Drugs Acting on the Respiratory Tract ## Drugs Acting on the Upper Respiratory Tract ### Learning Objectives: - Define pharmacology Key terms. - Outline the underlying physiological events that occur with upper respiratory disorders. - Describe the therapeutic actions, indications, pharmacokinetics, contraindications, most common adverse reactions, and important drug-drug interactions associated with drugs acting on the upper respiratory tract. - Discuss the use of drugs that act on the upper respiratory tract across the lifespan. - Compare and contrast the prototype drugs with other agents in their class and with other classes of drugs that act on the upper respiratory tract. - Outline the nursing considerations, including important teaching points, for patients receiving drugs acting on the upper respiratory tract. ## Key Terms: - **Expectorant**: helps to clear thick mucus from the respiratory tract. - **Antihistamines**: block the release of histamine. - **Mucolytics**: thin the mucus. - **Antitussives**: depress cough. - **Decongestants**: reduce swelling in the nasal passages. - **Cilia**: tiny hairs that line the respiratory tract. - **Common cold (URT)**: a viral infection of the upper respiratory tract. - **Rebound congestion**: occurs when a decongestant wears off. - **Seasonal Rhinitis**: allergic reaction to seasonal pollen. - **Sinusitis**: inflammation of the sinuses. - **Sneeze**: a reflex that helps to clear the nasal passages. - **Ventilation**: the process of breathing. - **Defense Mechanisms**: ways that the body protects itself from disease. ## Histamine - Sub released in case of inflammation. - Causes secretion. - Causes airway narrowing. ## Understanding the Common Cold - Most caused by viral infection (rhinovirus or influenza virus). - Virus invades tissues (mucosa) of upper respiratory tract, causing upper respiratory infection (URI). - Excessive mucus production results from the inflammatory response to this invasion. - Fluid drips down the pharynx into the esophagus (lower respiratory tract), causing cold symptoms: sore throat, coughing, upset stomach. - Irritation of nasal mucosa often triggers the sneeze reflex. - Mucosal irritation also causes release of several inflammatory and vascoactive substances, dilating small blood vessels in the nasal sinuses and causing nasal congestion. - Involves combined use of antihistamines, nasal decongestants, antitussives, and expectorants. - Treatment is symptomatic only, not curative. - Difficult to identify whether cause is viral or bacterial - Treatment is "empiric therapy," treating the most likely cause. - Antivirals and antibiotics may be used, but a definite viral or bacterial cause may not be easily identified. ## Pediatric Concerns - In 2008, the U.S. Food and Drug Administration (FDA) issued recommendations that over-the-counter (OTC) cough and cold products not be given to children younger than 4 years of age and extreme caution in children 4 to 6 years of age. - Evidence that such medications are simply not effective in small children. - Parents are advised to consult their children's pediatricians on the best ways to manage these illnesses. - A 2010 study showed a dramatic decrease in young children's emergency department visits since the 2008 FDA recommendation. ## Adults & Geriatric Concerns - Adults may inadvertently overdose on these agents when taking multiple OTC preparations to help them get through the misery of a cold or flu. - The (safety) for the use of these drugs during pregnancy and lactation has not been established. - Older adults frequently are prescribed one of these drugs. - Older adults are more likely to develop adverse effects associated with the use of these drugs, including sedation, confusion, and dizziness. - Safety measures may be needed if these effects occur and interfere with the patient's mobility and balance. - Older adults also are more likely to have renal and/or hepatic impairment related to underlying medical conditions, which could interfere with the metabolism and excretion of these drugs. ## Sites of Action of Drugs Working on the Upper Respiratory Tract - **Antitussives**: Block the cough reflex (Medulla) - centrally. - **Decongestants**: Decrease the blood flow to the upper respiratory tract, and decrease the overproduction of secretions. - **Antihistamines**: Cells - Block the release or action of histamine that increases secretions and narrows airways ## Drugs Used to Treat Upper Respiratory Infections # 2 - **Expectorants**: Increase productive cough to clear airways. - **Mucolytics**: Increase or liquefy respiratory secretions to aid clearing of airway. ## Oral Decongestants - Actions: Decrease nasal congestion related to the common cold, sinusitis, and allergic rhinitis. - Shrink the nasal mucous membrane by stimulating the alpha- adrenergic receptors in the nasal mucous membranes. - Indications: Promotion of drainage in the sinuses and improving air flow. - Pharmacokinetics: Well absorbed, widely distributed in the body. Metabolized in the liver and primarily excreted in urine. - Contraindications: Any condition that might be exacerbated by sympathetic activity - Adverse Effects: Rebound congestion, Sympathetic effects. - Drug-Drug Interactions: OTC products that contain pseudoephedrine; taking concurrently can cause serious side effects. - Nursing Considerations: Assess: (PP: 2889-2891) History, Physical Exam and known allergy, Pregnancy, lactation, hypertension, CAD, Hyperthyroidism, diabetes mellitus, or prostate enlargement, Orientation, reflexes, and affect, Evaluate respiration and adventitious sounds to monitor drug effectiveness, Monitor urinary output to evaluate for urinary retention. ## Prototype Oral Decongestants - **Prototype Summary: Pseudoephedrine** - **Indications: Temporary relief of nasal congestions caused by the common cold, hay fever, sinusitis; promotion of nasal and sinus drainage; relief of eustachian tube congestion.** - **Actions: Sympathomimetic effects, causes vasoconstriction in mucous membranes of nasal passages resulting in their shrinkage, which promotes drainage and improvement in ventilation.** - **Pharmacokinetics** - **Route**: Oral - **Onset**: 30 min - **Duration**: 4-6 h - **Adverse Effects**: Anxiety, restlessness, headache, dizziness, drowsiness, vision changes, seizures, hypertension, arrhythmias, pallor, nausea, vomiting, urinary retention, respiratory difficulty. ## Antihistamines and Histamine Antagonists - **Histamine is a maior inflammatory mediator in many allergic disorders:** - Allergic rhinitis (e.g. hay fever and mold, dust allergies) - Anaphylaxis shock. - Angioedema - Drug fevers - Urticaria (itching) - Insect bite reactions - **Antihistamines have several properties:** - Antihistaminic - Anticholinergic - Sedative ## Antihistamines - **H1 antagonists (also called H1 blockers):** -Examples: chlorpheniramine, fexofenadine (Allegra), loratadine (Claritin), cetirizine (Zyrtec), diphenhydramine (Benadryl) - **Relieve respiratory symptoms and treat allergies** - **First-generation and second-generation antihistamines include:** - Brompheniramine (J-Tan) - Carbinoxamine (Histex, Palgic) - Chlorpheniramine(Aller-Chlor) and many others. - **H2 blockers of H2 antagonists:** Used to reduce gastric acid in peptic ulcer disease. - **Examples: cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), nizatidine (Axid)** ## Antihistamines - **Actions**: Selectively block the effects of histamine at the histamine-1 receptor sites, decreasing the allergic response. - Anticholinergic and antipruritic effects. - **Indications**: Seasonal and perennial allergic rhinitis, allergic conjunctivitis, uncomplicated urticaria, and angioedema. - **Pharmacokinetics**: Well absorbed, metabolized in the liver, excreted in urine and feces - **Contraindications**: Pregnancy and lactation. ## Antihistamines - **Caution**: Renal or hepatic impairment, History of arrhythmias - **Adverse Effects:** Drowsiness and sedation, Anticholinergic effects - **Drug-Drug Interactions:** Vary based on the drug. ## Prototype Antihistamines - **Prototype Summary: Diphenhydramine** - **Indications**: Symptomatic relief of perennial and seasonal rhinitis, vasomotor rhinitis, allergic conjunctivitis, urticaria, and angioedema; also used for treating motion sickness and parkinsonism and as a nighttime sleep aid and to suppress coughs. - **Actions**: Competitively blocks the effects of histamine at histamine-1 receptor sites; has atropine-like antipruritic and sedative effects. - **Pharmacokinetics** - **Route**: Oral, IM, IV - **Onset:** 15-30 min, 20-30 min, Rapid - **Peak:** 1-4 h, 1-4 h, 30-60 min - **Duration**: 4-7 h, 4-8 h, 4-8 h - **Adverse Effects**: Drowsiness, sedation, dizziness, epigastric distress, thickening of bronchial secretions, urinary retention, rash, bradycardia. ## Nursing Considerations for Antihistamines - **Assess**: (PP: 2911-2913) - History and Physical Exam and known allergy - Pregnancy or lactation; and prolonged QT interval, renal or hepatic impairment - Skin, orientation, affect, and reflexes - Respirations and adventitious sounds - Appropriate lab values ## Questions 1. Which of the following is an adverse reaction to topical nasal steroids? - Increased nasal drainage - Rebound effect - Suppression of healing. - Local ulceration *ANS: C* *Adverse Effects: local burning, irritation, stinging, dryness of the mucosa, and headache; suppression of healing can occur in a patient who has had nasal surgery or trauma.* 2. A 4-year-old is brought to the emergency room in shock. The mother states she found the child eating her iron-fortified vitamin pills about 2 ½ hours ago. The mother estimates the child ate close to 200 tablets. What medication would you expect the physician to order for the treatment iron toxicity? - Deferoxamine mesylate - Methoxy polyethylene glycol-epoetin beta - Sodium ferric gluconate comlex - Levoleucovorin *Answer: A.* *Rationale: Supportive measures to deal with shock, dehydration, and gastrointestinal damage will be necessary. In addition, an iron-chelating agent such as deferoxamine mesylate may be tried.*