Vol. 16 •Issue 4 • Page 34
Drug Data
Examining Asthma Guidelines
Physicians can focus on low-intensity, high-yield therapy for positive results.
For more than 15 years, the National Institutes of Health and the National Asthma Education and Prevention Program have authored asthma guidelines in an attempt to decrease the endemic level of asthma morbidity in the U.S.
Still, asthma remains a major cause of emergency care visits, hospitalizations, and missed work and school days, which demonstrates the incomplete success of these strategies.1
Two important issues relate to this paradox. First is the problem of applying asthma guidelines, which requires wide dissemination to primary care physicians who provide asthma care.2 Evidence suggests applying the guidelines in clinical practice hasn’t been highly successful.3,4 It also has been difficult to subject asthma guidelines to controlled clinical trials.
A second problem is the complexity of the guidelines and the inclusion of information that either wasn’t evidence-based or was controversial or invalid.5-12 While attempts have been made to apply the principles of evidence-based medicine in the latest guideline updates, their length and consequent density detract from the goal of providing guidance to primary care providers.13
This article aims to simplify matters and presents evidence- and experience-based low-intensity measures that offer favorable outcomes for asthma management. These measures have been associated with highly successful results.14
Which asthma is which?
Asthma is a heterogeneous syndrome with different phenotypes. Generally, it can be diagnosed from responses to six evaluation questions:
1. What’s the age of onset of lower respiratory symptoms?
2. Are symptoms only associated with the clinical symptoms of a viral respiratory infection?
3. Are there extended periods between episodes of respiratory symptoms where there’s no cough or wheeze?
4. Is there a seasonal variation in symptoms, and does the season match those of inhalant allergens or the season of increased viral respiratory infections?
5. Are respiratory symptoms related to specific environmental exposures?
6. Are lower respiratory symptoms occurring daily for extended periods?
Intermittent asthma is purely episodic with no presence of symptoms or signs between current acute exacerbations. It’s commonly brought on by a common cold virus and is particularly frequent in young children.15
Seasonal allergic asthma’s symptoms only appear during seasons when patients are exposed to certain outdoor inhalant allergens. Similarly, occupational asthma symptoms stem from specific allergens or irritants in the workplace.
In chronic asthma, with or without seasonal allergic exacerbations, patients present continuous or frequently recurring symptoms. Persistent airway obstruction can be determined with spirometry.
Finally, a diagnosis of indeterminate asthma may be used as a temporary classification when the symptom duration or history doesn’t permit a clear picture of the pattern. In these cases, prospective monitoring of clinical course is needed.
As a general rule, asthma should be considered in the differential diagnosis when recurrent cough, expiratory wheeze, dyspnea, exercise intolerance, or diagnoses of recurrent bronchitis or pneumonia occur without other explanation.16 The diagnosis is confirmed if a patient demonstrates complete or nearly complete response to an inhaled beta2-agonist and/or a short course of relatively high-dose systemic steroids such as prednisone or prednisolone.
It’s important to note that failure to diagnose the symptoms of lower airway inflammation as asthma often results in inappropriate diagnoses of pneumonia or bronchitis, which leads to ineffective and unnecessary use of antibiotics.17,18 On the other hand, asthma is over-diagnosed, which also results in unnecessary and ineffective medication.19-21
Treating acute symptoms
Inhaled beta2-agonists are the first-line treatment for acute asthma symptoms. These drugs, including albuterol, levalbuterol, and pirbuterol only should be used as needed for cough, wheezing, or labored breathing. Bronchodilators are of no value to patients when used on a scheduled basis and may be deleterious for some.
When administering inhaled beta2-agonists, use the simplest age-appropriate delivery method. Be sure to demonstrate the proper usage of metered dose inhalers, valved holding chambers, and spacers before sending a patient home with these drug delivery devices.
Two to four inhalations is usual for beta2-agonist therapy, but up to six inhalations can be used. This is equivalent in clinical effect to the most common dosage by nebulizer.
Children younger than 3 years old can use an albuterol MDI in conjunction with a valved holding chamber with a soft, flexible mask. Dosing is two to six actuations, one at a time with four to five breaths after each activation to evacuate the chamber, repeated as needed. For preschoolers and kindergarteners who will cooperate by sealing their lips around a mouthpiece, the same dose of albuterol should be administered via MDI and valved holding chamber without the mask.
Children ages 6 to 8 can be instructed to use a breath-actuated MDI, which avoids the need for a holding chamber or spacer. Two to six inhalations of pirbuterol acetate inhalation aerosol or albuterol sulfate inhalation aerosol are recommended and may be repeated as needed. The same dosing of these drugs is indicated for adults and children ages 8 and older, with the option of using an albuterol MDI instead.
In cases of severe acute asthma in the emergency room, ipratropium aerosol may be administered by nebulizer. The dosage is 0.5 mg ipratropium with 2.5 to 5 mg albuterol when response to a beta2-agonist is inadequate to relieve a patient’s respiratory distress.
Oral therapy
When bronchodilator subresponsiveness is identified by incomplete resolution of symptoms and signs from repeat bronchodilator use, an oral corticosteroid should be added to acute asthma treatment. Subresponsiveness most commonly is associated with viral respiratory induced exacerbations. It results in decreased response to the bronchodilator or increased frequency of use with shorter durations of benefit.22
Because there are insufficient dose-response data to support recommendations based on weight or body size, empirical dosing is based solely on our experience that lower doses less reliably provide complete cessation of symptoms. (For dosing, see Table.)
Lower doses certainly will be adequate for some patients. Minor side effects may require limiting dosage in some patients to once a day in the morning only.
Oral corticosteroids prednisone, prednisolone, methylprednisolone, and dexamethasone usually are prescribed as tablets. For patients of any age who can’t swallow tablets intact, oral disintegrating tables are available. Additionally, liquid formulations of prednisolone are available for young children. Parenteral forms of oral corticosteroids are indicated only when physicians are concerned about oral retention.
These medications shouldn’t be tapered and should be continued until the patient is asymptomatic for a 24-hour period. This usually takes five to seven days. The patient should be re-evaluated if he or she isn’t improving within five days or is asymptomatic within 10 days.23-25
In the event of any side effects, the patient should discontinue the evening dose. The most common side effects are flushing, irritability, and insomnia. As a precaution, unimmunized patients exposed to chickenpox should receive appropriate prophylactic anti-viral treatment.
Maintenance medications
Guidelines indicate maintenance therapy should be used daily to prevent persistent symptoms in patients with seasonal allergic or chronic clinical patterns of asthma. Maintenance drugs are of no value for preventing or treating viral respiratory infection-induced asthma.26-28
Initial maintenance therapy can be achieved with inhaled corticosteroids (ICS), which are first-line medications for persistent symptoms.
Fluticasone propionate hydrofluoroalkane (HFA) (110 mcg) or beclomethasone dipropionate HFA (80 mcg) can be delivered as one inhalation twice daily by MDI. For infants and toddlers, use fluticasone and beclomethasone with a valved holding chamber with a mask. Most children will be able to use the chamber without the mask by age 4.
For older children and adults who can inhale deeply and hold their breath during treatment, budesonide inhalation powder is recommended with a dose of one inhalation twice daily.
As an alternative to ICS, the guidelines recommend montelukast for mild persistent asthma symptoms. Montelukast, a leukotriene antagonist, is convenient and free of known side effects but less effective than inhaled corticosteroids. It’s appropriate as a trial for very mild chronic asthma in younger children.
Montelukast is dosed as a 4 mg sprinkle, 4 or 5 mg chewable tablet, or 10 mg tablet. It should be taken once a day.
LABAs
In the event a conventional dose of ICS doesn’t maintain asthma control, the combination of an ICS and long-acting beta2-agonists (LABA) can be added to asthma therapy as fluticasone/salmeterol dry powder inhaler or MDI, or budesonide/formeterol MDI. Salmeterol and formoterol are LABAs that provide a substantial additive effect to ICS for patients not adequately controlled with a usual dose of ICS.
In a small subpopulation of patients, LABAs may decrease the bronchoprotective effect of inhaled beta2-agonists and worsen asthma control; however, these adverse effects appear to be related to genetic differences in the beta2-adrenergic receptor.29,30 Monitoring for the occasional patient made worse from the addition of a LABA is essential.
Slow-release theophylline
If a LABA worsens asthma control and an added agent is required, physicians can prescribe slow-release theophylline. Research shows it to be about as effective as salmeterol for additive effect to ICS without decrease in beta2-agonist bronchoprotective effect.31
Begin theophylline treatment with 10 mg/kg/day divided twice daily to a maximum of 150 mg twice daily. Then, increase the dosage in increments of 16 mg/kg/day to a maximum or 300 mg twice daily.
A patient’s serum theophylline concentrations must be monitored to attain peak serum concentrations of 10 to 15 µg/mL.31 Additionally, awareness of drug interactions and the effect of fever on theophylline levels is essential for safety.31
Criteria for asthma control
No matter the clinical course, treatment decisions for asthma should focus on the ultimate goal: effective control of the disease. Here are signs that a patient’s asthma management plan is working:
Physicians must stay on track and continue to follow scientifically validated programs to improve both provider and patient adherence to published asthma guidelines.
For a list of references, please look under the “From Print” toolbar on the left side of our home page at www.advanceweb.com/respmanager.
Miles Weinberger, MD, is a professor of pediatrics and director of the pediatric allergy and pulmonary division, University of Iowa, Iowa City.
Tips for Office Visits
1.Provide patients with verbal instructions reinforced with a simple written action plan that emphasizes the use of intervention measures for exacerbations.1
2.Monitor the patient’s clinical course. Return visits should be scheduled with adequate frequency to review the clinical course and reinforce instructions. Return visits for acute symptoms rarely should be needed because the use of intervention measures — including beginning a course of oral corticosteroids the day prior to the need for unscheduled medical care — generally will prevent that.
3.A careful environmental history is useful for indoor risk factors, both allergens and irritants. Exposure to tobacco smoke is a major factor in contributing to poor asthma control in smokers and non-smokers.2-13
4.Delivering acute care in the office, emergency treatment center, or hospital should be considered damage control, not successful asthma management.
For a list of references, please look under the “From Print” toolbar on the left side of our home page at www.advanceweb.com/respmanager.
–Miles Weinberger, MD