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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 ??

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

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

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

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

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