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Chapter 20 Drugs Affecting the Respiratory System Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Asthma and Chronic Obstructive Pulmonary Disease (COPD) • Asthma—chronic disease with abnormal reactivity of the bronchioles to triggers such as pollen, exercise, dust mites, and cigarette smoke • COPD—chronic bronchitis and emphysema result in loss of elasticity of lungs and airway constriction Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Bronchodilators • Selective β2-agonists – Provide symptomatic relief of wheezing and chest tightness – Do no prevent asthma attacks Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Indications • Selective β2-agonists selectively relax smooth muscle surrounding bronchioles. • Albuterol is fast-acting treatment of choice for symptoms of asthma occurring once or twice a week. • For persistent asthma, maintenance treatment with long-acting β2-agonists, such as formoterol and salmeterol, can sometimes be beneficial. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Indications (cont’d) • COPD treatment includes bronchodilators with beta-agonists and anticholinergic bronchodilators (ipratropium and tiotropium). • Actions include bronchodilation, relief of symptoms, and improved quality of life on a temporary basis. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration • Systemic circulation via mouth or injection • Direct local administration via inhalation, when possible, is preferred route due to direct delivery to airways, less systemic absorption, and fewer systemic side effects. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration (cont’d) • Metered dose inhaler (MDI)—small pressurized canister containing drug and mouthpiece for administration of set dose of drug at each activation • Nebulizer—device uses small compression pump to convert drug solution into a mist inhaled through a mouthpiece Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects • Selective β2 in repeated use or high doses can have deleterious cardiac effects such as fatal arrhythmias; jitteriness and increased heart rates are fairly common. • Beta-agonists can produce adverse CNS effects including anxiety, fear, tension headache, and tremor. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects (cont’d) • Dry mouth is common with ipratropium and tiotropium. • Tiotropium occasionally causes urinary retention and constipation. • Dry powder inhaler use is associated with throat irritation and coughing. • Use of a spacer with MDI can reduce associated bad taste and irritation. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tips for the Technician • Become familiar with respiratory drug delivery systems and equipment to provide customers with sound information. • Encourage inexperienced patients to look over inhaler instructions while still in the pharmacy. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Review The device that uses a small compressor pump for aid in the inhalation process is known as a: A) MDI B) Nebulizer C) Mister D) Spacer Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer B) Nebulizer A nebulizer uses a small compressor pump to convert the drug solution into a mist that the patient inhales through a mouthpiece. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Respiratory Corticosteroids • Glucocorticoids are endogenous hormones synthesized from cholesterol by the adrenal glands. • In humans, the most important of these hormones is cortisol. • Synthetic derivatives of cortisol are used for their anti-inflammatory effects in a variety of diseases. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Inhaled Corticosteroid Actions and Indications • Indicated for prevention of acute exacerbation of asthma • Inhibit many of the cells involved with inflammation in the bronchi and bronchioles and reduce airway edema • Peak effects take several weeks; therefore, not effective for acute asthma attacks Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Indications (cont’d) • As nasal spray, corticosteroids are also effective for allergic rhinitis, reducing congestion and itching within a few hours to days. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration • Intravenous • Oral • Inhalation • Nasal spray Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects • Serious side effects are much less likely and less severe when medications are inhaled. • Long-term use of inhaled corticosteroids at maximal doses can cause minor suppression of cortisol production in the body. • Oral candidiasis Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tips for the Technician • Use special caution when dispensing inhalers available in different strengths. • Apply “shake well” label to MDIs. • Dry powder inhaler devices are not shaken before use. • Apply auxiliary labels to include MDI use, rinse mouth after using, and cleaning mouthpiece after every use. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Review Dry powder inhalers should be shaken well to activate before administering. A) True B) False Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer B) False Dry powder inhaler devices are not shaken before use. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Alternative Pulmonary Anti-Inflammatory Drugs • The mast cell stabilizers cromolyn and nedocromil are first-line drugs for longterm prevention of asthma in place of steroids or in addition to the regimen. • The leukotriene modifiers montelukast, zafirlukast, and zileuton allow reduction of doses of inhaled corticosteroids in some patients with chronic asthma. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Indications • Cromolyn and nedocromil inhibit release of histamine, leukotrienes, and other inflammatory chemicals by mast cells and other granulocytes. • Mast cell stabilizers are indicated for long-term management of asthma. • Cromolyn is indicated for treatment of allergic rhinitis and has been used offlabel for chronic urticaria (hives). Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration • Cromolyn and nedocromil are administered via inhalation for asthma. • Cromolyn is available in MDI and nebulizer as well as nasal spray for allergic rhinitis. • Nedocromil is available as MDI only. • Leukotriene inhibitors are administered orally. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects • Mast cell stabilizer side effects – Throat irritation, cough, dry mouth, and unpleasant taste in the mouth – Not absorbed from the respiratory tract; there are no systemic side effects attributable Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects (cont’d) • Leukotriene inhibitor side effects – Headache – GI upset – Hepatotoxicity, eosinophilia, and pain in rare instances Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tips for the Technician • Label MDIs with auxiliary “shake well” label. • Label zafirlukast to be taken on empty stomach. • Instruct patients to take medication as ordered, even when symptom free. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Methylxanthine Derivatives • Coffee, tea, and chocolate all contain methylxanthine derivates known to possess bronchodilatory effects. • Theophylline and the related drug aminophylline are the methylxanthine derivatives most often used for COPD and sometimes asthma. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Indications • Bronchodilator and minimal antiinflammatory effects in airways • Indicated for treatment of COPD, after use of anticholinergic and beta-agonist drugs • Indicated for asthma treatment; generally reserved for difficult-tocontrol asthma and when alternatives have failed Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration • Theophylline and its derivatives are available in extended-release tablets and capsules and rectal and injectable forms. • For IV administration, aminophylline is preferred. • Elimination is extremely variable from patient to patient, and serum levels are monitored to avoid toxicity. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects • Due to narrow therapeutic index, difficulty in dosing, individual response to drugs, and side effects, use of theophylline and related drugs is waning. • Side effects can include headache, irritability, nausea, vomiting, CNS stimulation leading to seizures, hypotension, and cardiac arrhythmias. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tips for the Technician • Be aware of dosing differences between theophylline products. • Be aware that many drugs and additives are incompatible with aminophylline intravenous solutions. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Allergic Rhinitis, Coughs, and Colds • Rhinitis—inflammation of mucous membranes of the nose – Treatment includes antihistamines, decongestants, and intranasal application of corticosteroids. – Preventative measures, such as environmental air filters, can be useful. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Allergic Rhinitis, Coughs, and Colds (cont’d) • Cough—a natural response to airway irritation and aids process of clearing foreign material • Coughs can be symptomatic of asthma, bronchitis, or simple viral infections. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Antihistamines • Reversible antagonists of the H1 receptor • Prevent typical effect of histamine stimulation at this receptor • First-generation antihistamines are nonselective and can activate H1 receptors in the CNS, which accounts for their sedating effects. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Antihistamines (cont’d) • Second-generation, “nonsedating” antihistamines are selective for peripheral H1 receptors. • Indicated for allergic reactions, including hives and itching of eczema • Diphenhydramine remains the standard antihistamine to which other drugs are compared. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration • Because of the variety of indications for use, antihistamines are available in the following formulations: – Oral – Injectable – Rectal – Topical Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects • Most common side effect of nonspecific antihistamines is sedation. • The second-generation antihistamine cetirizine is most likely to cause minimal drowsiness. • Lower antihistamine doses are recommended for elderly patients. • Children may exhibit paradoxical response. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tips for the Technician • Patients should be urged to read package labeling for warnings and contraindications of OTC antihistamines. • Auxiliary labels should be affixed to prescription warning of potential sedation and discouraging alcohol consumption. • Promethazine suppositories are stored in refrigerator and labeled accordingly. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Cough Suppressants, Decongestants, and Expectorants • Colds are the most common form of infection. • Patients can be aided with drugs indicated for short-term treatment of symptoms accompanying colds and other upper respiratory infections. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Indications • Pseudoephedrine, phenylephrine, oxymetazoline, and others are alphaagonists useful as nasal decongestants. • Opiate cough suppressants, including codeine, decrease the sensitivity of the cough centers in the CNS. • Expectorants such as guaifenesin promote the removal of sputum from the lungs. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Review A natural way for the body to clear foreign material is through coughing. A) True B) False Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer A) True Coughing is a natural response to airway irritation and aids the process of clearing foreign material. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Administration • Nasal decongestants are available as nasal sprays or drops. • Pseudoephedrine is most universally used and is available in tablets, capsules, chewable tablets, extendedrelease tablets, pediatric liquid, and infant drops. • Dextromethorphan is available in tablets, capsules, and liquids. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects • Rebound congestion can occur with nasal decongestants. • Elevation of blood pressure can occur with oral decongestant; people with glaucoma and cardiac disease and patients taking MAO inhibitors should avoid systemic decongestants. • Nausea and vomiting may occur with dextromethorphan or guaifenesin. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Side Effects (cont’d) • Both dextromethorphan and pseudoephedrine carry some risks of abuse and, by federal law, are stored behind the prescription counter. – Dextromethorphan can cause hallucinations when taken in extremely high doses. – Pseudoephedrine can be converted to the stimulant methamphetamine. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tips for the Technician • Any narcotic antitussive should be properly labeled with auxiliary warning instructions regarding drowsiness, avoidance of operation of complex machinery, and avoidance of alcohol consumption. • Any consumer questions regarding OTC preparations should be referred to the pharmacist. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins