ASTHMA
October 13, 1999

How Best to Manage Your Asthma

Though asthma medicine is not generally recommended for pregnant women, the greatest risk to the fetus is a mother's uncontrolled asthma.
The widespread obstruction of airways that causes asthma symptoms can be extremely frightening to patients, their families and friends. Fortunately, the obstruction is, usually, reversible — either spontaneously or with therapy.

Medical scientists now believe that asthma is characterized by chronic inflammation and is active even when you have no symptoms. As a result of the continuous airway inflammation, irritants such as air pollutants or allergens produce, from time to time, medical consequences for the asthmatic.

Many mechanisms cause asthma and they are not well understood. For practical reasons, we distinguish asthma associated with allergies from those for which allergy plays a less prominent role. Regardless of the cause, asthma is a disease that needs to be continually managed. The best way to do this is to pursue treatment through both drugs and non-pharmacologic therapies.

The primary goal of therapy is to reduce airway inflammation overall and manage flare-ups. Even though asthma is a disease of intricate physiology and genetics, it is clear that the environment — the setting in which it occurs — is very important. In the United States, data show that the patient's economic and social circumstances and the medical support system available to the patient are important factors affecting disability and death.

An educated patient is important to managing asthma successfully. The National Institutes of Health developed for doctors and patients Guidelines for the Diagnosis and Management of Asthma. The guidelines emphasize that though asthma is a chronic disease, the asthmatic's understanding of their environment and prescribed regimen is central to successful management of their disease.

Self Management Strategies
  1. Follow the treatment plan and make sure you do not run out of medication.
  2. Take the following steps to reduce anxiety:
    • Have your doctor give you written instructions or write them down yourself in his or her presence.
    • Make sure you understand the treatment plan.
    • Make sure you have "measurement instruments" (e.g., diaries, peak flow meters) so that you can monitor the severity of your disease.
    • Have your doctor demonstrate the use of meter-dose inhalers, spacers and other respiratory care devices while you are in the office.

Environmental Control Measures
Become aware of the environmental irritants that have the potential to cause flare-ups as well as those you know can trigger an attack so that you can develop avoidance strategies. Here are some common sense things you can do:

Outdoors Molds and pollens: During the "hay fever" season stay indoors with the air-conditioner on and close the windows.

Cold air: Scarves, masks protect against airway irritation from cold air.
Indoors Animal dander and saliva: Nearly half of American households have dogs and nearly one-third have cats. The relationship between symptoms and the presence of pets can often be established by boarding the pet for a two-week period. Remove pets, if possible; keep them out of bedroom.

Dust mites: These tiny insects, which have an established role in allergic asthma, are everywhere. High concentrations are reported in bedding, upholstery, carpeting and clothing. Cover pillows and mattresses in an airtight cover. Wash bedding in hot (130ºF/55ºC) water weekly. Remove carpets, if possible.

Cockroaches: Rid your home of cockroaches. In urban areas, being allergic to cockroaches is common and may make asthma worse.

Vacuum cleaners: Since vacuuming stirs-up fine dust particles, asthma patients should not do vacuuming. If you must, wear a mask and purchase a vacuum with a special HEPA (High Efficiency Particle) filter.

Sprays: Avoid (e.g., hair sprays)

Wood and kerosene stoves: The gases they give off are irritants.

Tobacco smoke: Do not smoke and avoid, wherever possible, second-hand smoke.

Humidifiers: They have been associated with molds that trigger allergies and should be avoided.
Removal of allergens and irritants Air conditioners: Using an air conditioner allows windows and doors to remain closed, thus reducing exposure to allergens, while also reducing indoor humidity. This is a good idea because suspended water particles often contain allergens.

Air cleaning devices: These can remove over 99% of breathable particles from the indoor environment. Some air cleaners clean the air electrostatically (ionizers), while others use mechanical (HEPA) filters.


Pharmacologic Management
For most asthmatics, pharmacologic management of asthma can be safe and effective, reducing symptoms, improving activity tolerance, preventing attacks and maintaining near normal lung function. Tailoring of individual regimens will depend on patient preferences, compliance issues, side-effects, convenience and cost.

The two main therapeutic classes of drugs for asthma are anti-inflammatory agents and bronchodilators. Anti-inflammatory agents reduce airway swelling and mucous secretion, while bronchodilators relax airway constriction.

Anti-inflammatory Agents
For the treatment of acute short-term asthma flare-ups, I usually administer a short course (7-14 days) of oral or injected steroids. Corticosteroids (Table 1) are the most effective/reliable anti-inflammatory agents. A steroid burst, over one to two weeks, is usually effective in treating severe acute flare-ups (e.g., prednisone 40 to 80 mg daily in adults or 1-2 mg/kg in children initially, which may be followed by tapering).

Table 1.
Commonly used preparations.
Parenteral Oral Aerosol
Methylprednisolone(Solu-medrol®) Prednisone(Deltasone®) Flunisolide(Aero-Bid®)
Hydrocortisone(Solu-cortef®) Methylprednisolone(Medrol®) Triamcinolone(Azmacort®)
Dexamethasone
(Decadron®)
Fluticasone
(Flovent®)
Beclomethasone
(Vanceril®/
Beclovent®)


For stable asthma, inhaled steroids are the anti-inflammatory agents of choice and are well tolerated over extended periods with minimal systemic effects.

Some preparations, however, particularly those used at high doses, may suppress the pituitary gland and, in children, may retard growth. The concern about these side-effects, with long-term use of nebulized (meter dose inhaler administered) corticosteroids, requires that alternative anti-inflammatory agents ("adjuncts") be considered: Anti-leukotrience agents (Zileuton®, Accolate® and Singulair®), cromolyn sodium(available as a spray or as a powder) for inhalational use or nedocromil sodium available as a spray. Anti-leukotriene agents are oral anti-inflammatory agents that are currently recommended for the management of mild to moderate disease.

Bronchodilator Therapy
Bronchodilators are used for the rapid control of asthma symptoms. The following three classes of bronchodilator therapy (Table 2) are currently used for the management of asthma.

Table 2.
Bronchodilators: actions and efficacy.
  Beta Agonists Methylxanthine Anticholinergics
Administration A,O,P O,P A
Duration of Action S,I,L I,L I
Efficacy +++ ++ +
Side-Effects ++ +++ +/-
Legend:
  1. Asthma is not an FDA approved indication for these agents.
  2. A=aerosol, O=oral, P=parenteral
  3. S=short (<2 hours), I=intermediate (4-6 hours), L=long (12 hours or greater)


While oral and parenteral bronchodilators do afford some flexibility, and are said to insure better compliance, these agents are most commonly administered by aerosol to reduce systemic side-effects. Methylxanthines, however, are not effective when given as an aerosol and are much less popular at this time.

General Approach to Management (Adults)
The approach to management is summarized in Table 3 below.

Table 3.
Asthma Treatment Protocols.
  Clinical Status Treatment
Mild Symptoms intermittent Inhaled corticosteroid (low dose)
Or cromolyn/nedocromil
Beta agonist as needed for symptoms
Leukotriene antagonists
Moderate Symptoms daily Inhaled steroid (high dose)
And/or cromolyn/nedocromil
Beta agonist as needed for symptoms*
Leukotriene antagonists
Severe Frequent symptoms Inhaled steroid (high dose)
And/or cromolyn/nedocromil
Beta agonist as needed for symptoms*
* With greater variability consider methylxanthines, long acting beta agonist by inhaler (for example, salmeterol [Serevent®]), steroid burst. NOTE: All these regimens call for the regular use of anti-inflammatory agents (primarily steroid inhalers), but recommend bronchodilators only as needed.


If You Are Pregnant
The treatment of asthma in pregnancy follows the same general principles as that of the non-pregnant asthmatic. It is generally desirable for the welfare of both mother and child to keep the patient relatively free from asthma. Inhaled medications are preferred because less of these medicines will reach the fetus but they should be prescribed if the asthma is not controlled by inhaled medication. Table 4 lists the FDA risk factor category of commonly used asthma medications. It needs to be stressed that the greatest risk to the fetus is uncontrolled asthma.

Table 4.
Risk to Fetus of Allergy and Asthma Medications During Pregnancy.
  Agent Risk Factor Category
Bronchodilators Albuterol C
Metaproterenol C
Terbutaline B
Theophylline C
Anti-inflammatory Cromolyn sodium B
Beclomethasone C
Prednisone Not Rated
Flunisolide C
Triamcinolone D
Antihistamine Chlorpheniramine B
Brompheniramine C
Terfenadine C
Astemizole C
Tripolidine B
A=Controlled studies no risk
B=No evidence of risk in humans
C=Risk cannot be ruled out
D=Positive evidence of risk
X=Contraindicated in pregnancy


In Development
Many new approaches and agents for the treatment of asthma have recently become available or are being tested:
  • Methotrexate: this chemotherapeutic agent has only been tested in small studies. Potential for serious toxicity. Not recommended at this time for routine care.
  • Cyclosporin A: Immunosuppressive agent that stops T-lymphocyte production. Role in asthma uncertain. Potential for serious toxicity.
  • Gold salts: Many small studies. Efficacy and role still uncertain.
  • IV Immunoglobulins: May act as blocking antibody reducing allergy. Role uncertain.
  • Ketotifen: Widely used in other countries. Trials in U.S. have not demonstrated efficacy.
  • Triacetyl oleandomycin: Related to antibiotics. Presumably works by altering steroid metabolism.
  • Xopenex;®(R-albuterol): Recently approved, the "active" form of albuterol has fewer side-effects.

Others:
  • Long acting/selective anticholinergics
  • Selective phosphodiesterase inhibitors
  • Neurokinin-receptor antagonists
  • Colchicine
  • Lidocaine (aerosol)
  • Monoclonal antibodies directed against adhesion molecules (anti-inflammatory)
  • Potassium channel activators


Summary
Patient education, in particular, the avoidance and removal of environmental irritants, is the foundation of asthma management. Any program must be tailored to the patient's individual needs. Complementing this approach is an effective array of agents available to manage both the inflammatory component of asthma, as well as its acute flare-ups. All degrees of asthma require anti-inflammatory therapy. The agents of choice in this category are inhaled steroids. Alternatives exist in the form of cromolyn, nedocromil and, most recently, anti-leukotriene agents. Acute flare-ups require bronchodilator agents administered for symptoms.
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