Bronchodilator

Bronchodilators relax smooth muscles around the bronchioles restoring airflow to the lungs. Sympathomimetics are bronchodilators that increase the production of cyclic AMP, causing dilation of the bronchioles by acting as adrenergic agonistic.

Some sympathomimetics are selective to particular adrenergic receptors, which are referred to as alpha1, beta2 and beta2-adrenergic. Other sympathomimetics are non-selective sympathomimetic that affect all types of adrenergic receptor sites.

Epinephrine (adrenalin) is a non-selective sympathomimetic that is given subcutaneously, IV, or via an endotracheal tube in emergency situations to restore circulation and increase airway patency.

Selective beta2-adrenergic agonists have fewer side effects then epinephrine and are given by aerosol or as a tablet. These include albuterol (Proventil, Ventolin), isoetharine HCl (Bronkosol), metaproterenol sulfate (Alupent), samleterol (Serevent), and Terbulaline SO4 (Brethine).

Ipratropium bromide (Atrovent) is an anticholinergic drug that inhibits vagalmediated response by reversing the action of acetylcholine, producing smooth muscle relaxation. It is a newer medication that dilates bronchioles with few systemic effects. Ipratropium bromide (Atrovent) is used five minutes before glu-cocorticoid (steroid) or cromolyn are inhaled so the bronchioles dilate enabling the steroids to be deposited in the bronchioles. Sometimes ipratropium bromide is combined with albuterol sulfate (Combivent) to treat chronic bronchitis for more effective and longer duration than if each is used alone.

Methylxanthine (xanthine) derivatives are a second group of bronchodilators used to treat asthma. They include aminophylline, theophylline, and caffeine, which stimulate the central nervous system (CNS) to increase respirations, dilate coronary and pulmonary vessels, and increase urination (diuresis).

Leukotriene Modifiers

Bronchoconstrictors cause the contraction of smooth muscle around the bronchi restricting airflow to the lungs. Leukotriene (LK) is the primary bronchocon-strictor that increases migration of eosinophils, increases mucous production, and increases edema in the bronchi resulting in bronchoconstriction.

There are two types of Leukotriene (LK) modifers: LT receptor antagonists and LT synthesis inhibitors. These are effective in reducing the inflammatory symptoms of asthma triggered by allergic and environmental stimuli.

Leukotriene (LK) modifiers include Zafirlukast (Accolate), zileuton (Zyflo) and nontelukast sodium (Singulair).

Anti-inflammatory

Chronic obstructive pulmonary disease causes inflammation in the respiratory tract that results in respiratory distress for the patient. Glucocorticoids (steroids) are the primary medication given to reduce the inflammation. You'll learn more about glucocorticoids (steroids) in Chapter 12.

Glucocorticoids (steroids) can be administered orally, via aerosol inhalation, intramuscularly, and intravenously. Glucocorticoids used for aerosol inhalation use beclomethasone (Beconase, Vanceril), dexamethasone (decadron), flunisolide (Aerobid, Nasalid), or triamcinolone (Azmacort, Kenalog, Nasacort).

Glucocorticoids used for other routes include betamethasones (Celestone), cortisone acetate (Cortone acetate, Cortistan), dexamethasone (Decadron), hydrocortisone (Cortef, Hydrocortone), methylprednisolone (Medrol, Solu-Medtol, Depo-Medrol); and prednisolone, prednisone, and triamcinolone (Aristocort, Kenacort, Azmacort).

Expectorant

As you learned previously in this chapter, an expectorant—referred to as mucolytics—liquefies and loosens thick mucous secretions so they can be removed through coughing. A commonly prescribed expectorant for chronic obstructive pulmonary disease is acetylcysteine (Mucomyst), which is administered by nebulizor five minutes after the patient receives a bronchodilator.

Acetylcysteine should not be mixed with other medications and can cause nausea, vomiting, oral ulcers (stomatitis), and a runny nose. Acetylcysteine is also an antidote for acetaminophen overdose if given within 12 to 24 hours after the overdose.

Mast Stabilizer Drugs

Mast cells release histamines, leukotrienes and other mediators of the inflammatory process. Mast cell stabilizer drugs inhibit the early asthmatic response and the late asthmatic response. They have no bronchodilator effect nor do they have any effect on any inflammatory mediators already released in the body. They are indicated for the prevention of bronchospasms and bronchial asthma attacks. They are administered by aerosol inhalation. The exact action of the drugs have not been determined. However, they are believed to have a modest effect in lowering the required dose of corticosteroids. The most common mast stabilizer drugs are cromolyn (Intal) and nedocromil (Tilade).

A list of drugs utilized in the treatment of lower respiratory tract disorders is provided in the Appendix. Detailed tables show doses, recommendations, expectations, side effects, contraindications, and more; available on the book's Web site (see URL in Appendix).

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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