Pharmacology II – Respiratory and Oxygenation

1. Pharmacology II – Respiratory and Oxygenation Kathy Plitnick RN PhD CCRN Georgia Baptist College of Nursing of Mercer University

4. Antitussives • Suppress cough • Narcotics • Codeine • Non-Narcotics • Dextromethorphan • Use: dry, nonproductive cough

5. Dextromethorphan • Available over-the-counter • Chemically related to opiates • Contraindicated in chronic cough • Caution in hepatic failure • Rare Side Effects • Interacts with other CNS depressants, Amiodarone, Quinidine, Alcohol

6. Decongestants • Relieve nasal obstruction • Adrenergic drugs • Constrict arterioles, reduce blood flow • Mainly alpha receptors • Oral, topical (sprays & drops) • Use: relieve rhinitis, preop nasal surgery • Contraindicated: HTN, CAD, glaucoma • Sudafed (pseudoephedrine) • Large doses: tachycardia, palpitations, lightheadedness

7. Antihistamines • Prevent effects of histamine • Inhibit smooth muscle constriction • Decrease capillary permeablity • Decrease salivation • Use: allergic rhinitis, anaphylaxis, drug allergies, transfusions, dermatologic, motion sickness, sleep • Contraindicated: glaucoma, prostatic hypertrophy, pregnancy, bladder obstruction

9. First Generation H1 Blockers • Bind to central & peripheral H1 receptors • CNS depression/stimulation • Anticholinergic effects • Interact with alcohol, CNS depressants • Safety precautions • Baseline assessment • Increase oral fluid intake • No driving

10. Diphenhydramine (Benadryl) • High incidence of drowsiness • Short term management - insomnia • Topical, oral, IM, IV • Hypotension • Half-life 1-4 hours

11. Second Generation H1 Blockers • Produce less sedation • Less CNS depression • Fexofenadine (Allegra) • Rapid absorption • Half-life 14.4 hours • Caution in impaired renal function • Obtain thorough history of allergic reaction • Baseline pulmonary assessment • Administration with food • Safety measures

12. Expectorants • Liquefy secretions • OTC preparations • Guaifenesin (Robitussin) • Decreases adhesiveness, surface tension • Well absorbed • Symptomatic relief of cough • Do not use with persistent cough • Rare side effects • Assess type, severity of cough • Increase fluid intake, Humidity

13. Mucolytics • Inhalation – liquefy mucus • Nebulized, Direct instillation • Acetylcysteine (Mucomyst) • Reduces viscosity • Acetaminophen overdose • Effective in 1 minute • Transient odor, irritated throat, N/V, bronchospasm

14. Bronchodilators • Adrenergic drugs that stimulate beta2 receptors, stimulate adenyl cyclase, increase production of cAMP, produces bronchodilation • Xanthines: Theophylline • Inhibits phosphodiesterase • Inhibits pulmonary edema • Helps cilia clear mucus • Strengthens diaphragm

15. Theophylline • Contraindicated: gastritis, PUD • Uses: asthma, bronchitis, emphysema • Aminophylline by continuous infusion • Administer with water, after meals • Monitor plasma levels: 10-20 mcg/ml • Avoid smoking • Signs of toxicity: anorexia, N/V, dizziness, shakiness, restlessness, tachycardia, hypotension, seizures

16. Beta Agonists – Albuterol • Available oral, inhalation • Bronchodilation occurs 5-15 minutes • Stimulates smooth muscle receptors in lungs, uterus, skeletal muscle • Side Effects: throat irritation, palpitations, Tachycardia, hypertension, finger tremors • Always administer prior to anti-inflammatory inhalers, steroids

17. Anticholinergics : Ipratropium/Atrovent • Block action of acetylcholine in bronchial smooth muscle • Reduces GMP • Halts bronchoconstriction due to PNS • Administration by inhalation, intranasal • Ineffective in acute bronchospasm • Adverse Effects: cough, nervousness, nausea, GI, headaches

18. Atrovent • Do not use as an emergency agent • MDI’s – allow up to 1 minutes between puffs • Rinse mouth after administration

19. Anti-inflammatory: Glucocorticoids/Beclomethasone • Increase number of beta receptors • Increase responsiveness of beta receptors • Produces smooth muscle relaxation • Inhalation: decrease inflammatory cells, and swelling • Chronic asthma • Contraindicated: systemic fungal infections

20. Beclomethasone • Caution: active infection, DM, PUD, HTN, CHF, RI • Rinse mouth after administration • Teach proper inhalation technique • Use bronchodilators first

21. How Can You Avoid This Medication Error? • Mr. C, 66 years old, has worsening COPD. At his last office visit, the MD added ipratropium (Atrovent) and beclomethasone (Vanceril) to his beta-adrenergic (Alupent) inhaler. He visits the office complaining of severe dyspnea. You quickly grab his Atrovent inhaler to administer a PRN dose and try to get him to relax. • What drug error has occurred, and how could this be avoided ??

22. Solution • Acute dyspnea: only short-acting beta adrenergic bronchodilators should be used (Alupent) • Teach which inhaler to use in an emergency • When prescribed multiple inhalers, canister should be a different color or marked in some way • Know what the patient is prescribed

23. Mast Cell Stabilizers: Cromolyn Sodium (Intal) • No direct anti-inflammatory • Prevents release of mast cells after exposure to allergens • Prophylactic mgmt severe asthma, seasonal rhinitis • Available oral, inhalation, nasal spray, ophthalmic

24. Cromolyn Sodium • Use proper inhalation technique • Wait 10 minutes between doses • Rinse mouth after administration • Assess respiratory status

25. Leukotriene Receptor Antagonists: Zafirlukast (Accolate) • Binds to leukotriene receptors • Inhibits bronchoconstriction • Reduces airway edema, smooth muscle constriction • Rapidly absorbed • Half-life 10 hours • Chronic treatment

26. Zafirlukast (Accolate) • Aspirin increases concentration • Warfarin increases PT • Monitor SGPT • Side effects: headache, diarrhea, gastritis • Baseline LFT’s • Assess respiratory function • Increase fluid intake • Not for acute episodes • Take on empty stomach