1 Chapter 7 Respiratory Drugs

2 Ventilation  Refers to the movement of air in and out of the lungs through a series of air passages.  Nose  Mouth  Trachea  Bronchial tree  The upper portion of the respiratory system is mainly responsible for conditioning inhaled air from the environment.

3  To maintain normal ventilatory function, it is critical that the upper respiratory system adjust the temperature and humidify the inhaled air as well as provide filtration of the contaminants in the ambient air.

4  Filtration of inspired air occurs mainly as the inhaled air passes over the mucus lined epithelium of the trachea.  The branches of the bronchial tree are lined with smooth muscle, which adjusts the constriction and dilation of the airways in response to the needs of the body.

5 Respiratory System  In the respiratory system, receptor specificity is a very important issue and has prompted a continued development in many of the agents discussed in this chapter.

6  One of the major systems regulating the respiratory system is the autonomic nervous system  A main function of the autonomic nervous system is to regulate smooth muscle tone in the respiratory system and thereby maintain the balance between bronchoconstriction and bronchodilation.

7 Asthma  Millions of people in the United States have asthma and billions of dollars are spent annually on the care of these individuals.  Asthma is a condition of the respiratory system involving narrowing (bronchoconstriction) and inflammation of the small air passages of the lower respiratory system.

8  Technically, asthma, exercise induced asthma (EIA), and exercise induced bronchoconstriction (EIB) are separate conditions and treated differently.  True asthma is characterized by both bronchoconstriction and inflammation in the respiratory tract.

9  Exercise is a trigger for approximately 80% to 90% of individuals with asthma.  Individuals with EIA, must have excellent control of their underlying asthma in order to be able to prevent asthma exacerbations during physical activity

10  Exercise-induced bronchoconstriction without active inflammation is technically not exercise induced asthma.  Exercise-induced bronchoconstriction occurs in approximately 11% of individuals without asthma and the rate may be as high as 50% for elite athletes.

11  In asthmatic reaction, inflammatory response = increase in mucus production to protect body  Excess coating can lead to air-flow restriction  Another mechanism to protect body is bronchoconstriction

12  The classic signs of an acute asthma exacerbation are:  Shortness of breath  Wheezing following exercise  Other signs and symptoms include:  Cough  Headache  Stomach cramps  Pain or tightness in the chest  Nausea

13  These signs and symptoms typically start 6 to 8 minutes after the onset of strenuous exercise but may not reach maximum severity until up to 15 minutes after the cessation of exercise.  Typically, spontaneous return to baseline respiratory function occurs within a 20- to 60-minute period following onset of symptoms.

14 Asthma Treatment Options  Certified athletic trainers often interact with athletes who use an inhaler, or more formally known as metered dose inhalers (MDIs).  Most true asthma exacerbations have both an inflammatory and bronchoconstriction component.  The use of medications to control and treat asthma may address one or both of these problems.

15  Currently, the most widely accepted approach to asthma treatment is to initially control the inflammatory process associated with the trigger and thus prevent bronchoconstriction onset.  This approach is reflected in the switch from heavy dependence on “rescue” inhalers to the increased use of controlling agents.

16  With respect to exercise-induced asthma, the athlete typically experiences little or no active inflammatory process and the primary complication is the bronchoconstriction associated with the exercise trigger.  The treatment for asthma and EIA are different.

17  Asthma exacerbations are categorized based on the severity and the frequency of the symptoms.  In general, asthma is broken down into four categories: (Table 7-1, pg 95)  mild intermittent  mild persistent  moderate persistent  severe persistent

18 Commonly Used Drugs for Asthma Control  Numerous pharmacological approaches are used to treat asthma.  Some factors that influence the choice of approach are severity and frequency of the exacerbations, as well as the convenience of using the drug.  The drugs used to treat asthma can be classified into two groups:  bronchodilators and anti-inflammatory agents (steroids and non-steroids).

19  It is generally accepted that anyone with persistent asthma should utilize a controlling agent for the inflammatory component in conjunction with a “rescue” inhaler for the bronchoconstriction.  The role of corticosteroids in asthma, and respiratory care in general, is to combat inflammation of the airways associated with certain respiratory conditions.

20  Corticosteroids indirectly prevent inflammation-mediated bronchoconstriction through the inhibition of prostaglandins and leukotrienes.  In addition, corticosteroids reverse vascular permeability associated with the inflammation process.

21  Oral nonsteroidal asthma medications are an attractive alternative to the use of inhaled steroids in the control of asthma.  In addition, there is no fluctuation in delivery of the medication due to improper use of the MDI.  It is important to note that all individuals who use either steroids or nonsteroidals still need access to a “rescue” inhaler in the event of an asthma exacerbation

22 Rescue Inhalers  Table 7-2, pg 96 Exercise-induced Asthma  Causes:  water loss  heat exchange cooling the airways  Increased sodium intake  Must have formal diagnosis

23 Adverse Effects of Asthma Medications  MDIs have less serious adverse effects  Localized delivery of the medication  The adverse effects of beta-2 agonists are relatively minor.  Common adverse effects include nervousness, restlessness, trembling, throat irritation, and potential airway hypersensitivity.

24  Inhaled steroids, have localized side effects, such as throat irritation and hoarseness.  The inhaled steroid residue present in the mouth alters the bacterial environment, thus allowing for opportunistic yeast infections in the mouth.  To limit this problem, users are encouraged to rinse their mouth and brush their teeth after each use of an inhaler.

25  Oral steroids short-term and long-term adverse effects.  Short term – increased appetite, acne, poor wound healing, fluid retention, and insomnia  Long-term – avascular necrosis, osteoporosis, glaucoma, and decreased muscle mass

26  Adverse effects of inhaled nonsteroidal asthma medications  Bitter taste in mouth  Throat irritation  Dry mouth  Headache  Skin rash

27 Allergies  Are the result of some adverse environmental stimulus  Two classes of drugs are used for the treatment of allergies:  Antihistamines  Corticosteroids (nasal sprays).

28 Histamines  Histamine causes blood vessel dilation and subsequently an inflammatory response in the area affected.  Results in an inflammatory response noted by the classic allergy symptoms, such as runny nose, itchy and watery eyes, and sneezing.

29 Antihistamines  Antihistamines produce three general effects on the body:  Alteration of histamine action  Sedation  Anticholinergic activity (decreased salivation, dry mouth, and constipation)

30  Currently there are first- and second- generation antihistamines  The major differences between the two generations are:  The time they are active  1st generation = 4 to 6 hrs  2nd generation = up to 12 hrs  The extent to which they promote drowsiness  2nd generation are less sedating

31  Antihistamine drugs  Halt increased vascular permeability  Decrease smooth muscle constriction of the airways  First-generation antihistamines cross the blood brain barrier and cause sedation  Use a first-generation antihistamine during the evening (less expensive) and nighttime  Switch to a second-generation antihistamine during the daytime

32  Antihistamines result in decreased symptoms and increased patient comfort.  Their use is sometimes questioned.  Impeding these effects is not always a good thing.  The body produces mucus in an effort to protect the respiratory system.  Decreasing these functions may slow recovery.

33  Antihistamines may not be effective in decreasing nasal blockage.  Second-generation antihistamines are available with a decongestant.  Claritin-D and Allegra-D  A decongestant will assist with the resolution of the runny nose and head congestion.

34  Adverse effects of antihistamines  Mucous membrane dryness  Cardiac stimulation  Blurred vision  Urinary retention

35 Steroid Nasal Spray  Nasal steroid medications are specifically used for allergic rhinitis.  They are not for symptoms of the common cold.  Drugs are delivered locally.  Potential for nasal irritation, dryness, and epistaxis

36 Coughs and Colds  Runny nose, mild sore throat, and watery eyes are similar in both the common cold and allergic reactions.  Common cold refers to a nonbacterial infection of the upper respiratory system.

37 Cough and Cold Medications  Decongestants  vasoconstriction resulting in mucosal drying  Antihistamines  combat increased histamine = nasal congestion and mucosal irritation  Expectorants  facilitate the removal of mucous from the respiratory system  Antitussives  work to suppress coughing

38  Medications may contain a combination of decongestant, antihistamine, expectorant, and antitussive agents  Vicks NyQuil contains:  Acetaminophen  Pseudoephedrine, a decongestant,  Dextromethorphan, a cough suppressant  Antihistamine

39 Decongestants  Prolonged use of decongestants:  Headache  Nausea  Dry mouth and nose  Dizziness  Nervousness  Prolonged application of nasal spray (topical)  Can cause a rebound effect vasodilatation after the initial vasoconstriction decreases

40  Common decongestants  Pseudoephedrine (Sudafed)  Tetrahydroziline (Visine)  Oxymetazoline (Afrin)

41 Expectorants  Cough syrup to relieve the coughing linked to cold symptoms  Cough syrups can contain  Antitussive (cough suppressant)  Expectorant (promotes mucus clearance)  If the coughing linked with a cold is “nonproductive,” eliminate the nonproductive coughing

42  Mucus removal produced by the body during the common cold needs to be thin and mobile for the coughing to be productive.  Expectorants are available in two forms:  Mucolytic  Stimulant

43 Antitussives  Antitussives suppress the cough.  Use a central or a local mechanism.  Used for short periods of time.  Used to inhibit a cough via a central mechanism.  Cough center located in the medulla is targeted.

44  Dextromethorphan (DM) is the most common ingredient in OTC suppressing agents.  Robitussin products, Tylenol cold products, and NyQuil medications.  Physician can prescribe a narcotic antitussive.  Codeine or hydrocodone.  Addictive property of narcotics.  Duration of the prescription does not exceed 1 week.

45 Adverse Effects  OTC cold and allergy medications relatively show few serious adverse effects.  Participating in a sport while in a state of drowsiness could be dangerous.  Antihistamines (1st generation) can result in significant drowsiness even after the drug’s half-life is complete.

46  Antihistamines may cause anticholinergic effects such as  Mucus membrane dryness  Cardiac stimulation  Decreased gastrointestinal activity  Urinary retention  Decongestants can promote  Excessive drying of the nose and throat  Tachycardia and restlessness

47  Guaifenesin (cough syrups)  Dizziness  Headache  Nausea  Antitussives (Dextromethorphan)  Mild dizziness  Drowsiness  Nausea  Stomach cramps