Drugs For Treating Asthma Chapter 9 Sympathomimetic Agents

Drugs For Treating Asthma Chapter 9

Sympathomimetic Agents • Noninfectious respiratory diseases are divided into two groups – Asthma is characterized by reversible airway obstruction – Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airway obstruction • COPD is further divided into emphysema and chronic bronchitis

Sympathomimetic Agents - Continued • Beta-Adrenergic Agonists – Nonselective adrenergic agonist drugs stimulate beta receptors in the lungs and heart and alpha receptors in the heart – Epinephrine and isoproterenol are nonselective adrenergic agonists – Today, short- and long-acting β 2 -agonists are used to treat asthma and COPD – Β 2 -Agonists stimulate receptors in the lungs. – Stimulation of these receptors produces bronchodilation – Adverse effects include nervousness, tachycardia, and insomnia

Respiratory Drugs • Beta-Adrenergic Agonists – Short-Acting β 2 -Agonists • These drugs are used to treat acute asthma attacks. • They are usually administered via metered dose inhalers • They are available in tablet and liquid dose forms. • Short-acting β 2 -agonists are often used as prophylaxis prior to exercise or another known precipitating event

Long-Acting β 2 -Agonists • These agonists have a delayed onset of action and a longer duration of action • Onset of action is within 10 -20 minutes and the duration of action of 12 hours. • These drugs are used as maintenance therapy in the treatment of asthma and COPD

Metered Dose Inhalers (MDI) • These devices deliver the medication directly to the bronchioles • The total dose is kept low and side effects should be minimal • The inhaled dose can be accurately measured • Onset of action is rapid and predictable • They are compact, portable, and sterile • They can be difficult to use • Spacers are available which makes the inhaler easier to use • Adverse effects with MDI use include dry mouth

Corticosteroids • Steroids reduce the inflammation associated with airway obstruction – They also inhibit the release of inflammatory substances – Steroids are available as MDIs and oral and liquid dose forms – The MDI has become the most common dose form used in treating asthma and COPD

Corticosteroids - Continued • Corticosteroids significantly improve pulmonary function with a decrease in wheezing, tightness, and cough – These drugs are not used for acute attacks. – Chronic oral prednisone use is reserved for patients with severe asthma – Adverse effects are dependent upon dose form, frequency of intake, total dose, and any preexisting conditions

Corticosteroids - Continued • Prolonged systemic use can lead to adrenal suppression, poor wound healing, and immunosuppression – MDI use can lead to oral candidiasis. – Patients using inhaled steroids should be instructed to brush, floss, rinse, and spit, after each use

Leukotriene-Pathway Inhibitors • These drugs work by either preventing the synthesis of leukotrienes or by blocking leukotriene receptors – Leukotriene release produces bronchoconstriction, increased mucus secretion, mucosal edema, and increased bronchial hyperreactivity – These drugs are used to treat asthma and allergic rhinitis – Adverse reactions include irritation of the stomach mucosa, headache, and altered liver function tests

Cromolyn • Cromolyn inhibits mast cell degranulation. – It is used for the prophylaxis of asthma – It can be used in patients with chronic asthma or taken before exercise-induced asthma – Adverse effects include cough, dry mouth, nausea, and headache – It is available as a nebulizer or in a spinhaler dose form

Methylxanthines • Theophylline is the main drug in this category – It is a bronchodilator with a narrow therapeutic window – It is used to treat severe asthma and the bronchospasm associated with COPD – Side effects include CNS stimulation, cardiac stimulation, and GI upset

Anticholinergic Drugs • Ipratropium bromide is an inhaled anticholinergic drug that is used to treat asthma and COPD – Its anticholinergic effects produce a bronchodilating effect in the lungs – Side effects include dry mouth. The patient should rinse after each inhaler use to minimize dry mouth

Role of the Athletic Trainer • Educate the patient in regards to: – The type of medication they are taking – Specific effects in regard to athletic performance • Understand proper inhalation technique • Take action to adjust specific drug through consultation if necessary • Keep medication readily available • Monitor the patient during exercise • Know the medications the athletes are using